E50001-F710-A251-V4-4A00

Instruction manual
Types 3AH3 and 3AHc vacuum circuit
breaker operator modules
4.16 kV to 38 kV

www.usa.siemens.com/mvswitchgear
 Hazardous voltages and high-speed moving parts.

Will cause death, serious injury or property damage.

Always de-energize and ground the equipment before maintenance. Read

and understand this instruction manual before using equipment.
Maintenance should be performed only by qualified personnel. The use of
unauthorized parts in the repair of the equipment or tampering by
unqualified personnel will result in dangerous conditions which will cause
death, severe injury or equipment damage. Follow all safety instructions
contained herein.

Important Further, a qualified person shall also be

The information contained herein is general familiar with the proper use of special
in nature and not intended for specific precautionary techniques, personal
application purposes. It does not relieve the protective equipment, insulation and
user of responsibility to use sound practices shielding materials, and insulated tools and
in application, installation, operation and test equipment. Such persons are permitted
maintenance of the equipment purchased. to work within limited approach of exposed
Siemens reserves the right to make changes live parts operating at 50 volts or more, and
in the specifications shown herein or to shall, at a minimum, be additionally trained
make improvements at any time without in all of the following:
notice or obligation. Should a conflict arise
The skills and techniques necessary to
between the general information contained
distinguish exposed energized parts from
in this publication and the contents of
other parts of electric equipment
drawings or supplementary material or
both, the latter shall take precedence. The skills and techniques necessary to
determine the nominal voltage of
Qualified person
exposed live parts
For the purpose of this instruction manual a
qualified person is one who is familiar with The approach distances specified in NFPA
the installation, construction or operation of 70E® and the corresponding voltages to
the equipment and the hazards involved. In which the qualified person will be
addition, this person has the following exposed
qualifications:
The decision-making process necessary
Is trained and authorized to to determine the degree and extent of
de-energize, clear, ground and tag the hazard and the personal protective
circuits and equipment in accordance equipment and job planning necessary to
with established safety procedures. perform the task safely.
Is trained in the proper care and use of
protective equipment, such as: rubber
gloves, hard hat, safety glasses or face
shields, flash clothing, etc., in
accordance with established safety
practices.
Is trained in rendering first aid.
Note:
These instructions do not purport to cover all details or variations in equipment, nor to
provide for every possible contingency to be met in connection with installation,
operation or maintenance. Should further information be desired or should particular
problems arise that are not covered sufficiently for the purchaser’s purposes, the matter
should be referred to the local sales office.

The contents of this instruction manual shall not become part of or modify any prior or
existing agreement, commitment or relationship. The sales contract contains the entire
obligation of Siemens Industry, Inc. The warranty contained in the contract between the
parties is the sole warranty of Siemens Industry, Inc. Any statements contained herein
do not create new warranties or modify the existing warranty.

Table of Contents
Introductions 04 – 05

Receiving, handling and storage 06 – 08

Installation checks and functional tests 09 – 10

Vacuum interrupter/operator 11–27

Maintenance 28 – 41

Overhaul 42 – 46

Technical data and troubleshooting 47 – 55

3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Introduction

Hazardous voltages and high speed moving parts. Will

cause death, serious injury or property damage.
Always de-energize and ground the equipment before maintenance. Read
and understand this instruction manual before using equipment.
Maintenance should be performed only by qualified personnel. The use of
unauthorized parts in the repair of the equipment or tampering by
unqualified personnel will result in dangerous conditions which will cause
death, severe injury or equipment damage. Follow all safety instructions
contained herein.

Introduction Signal words

The type 3AH3 and type 3AH-compact The signal words “danger,” “warning” and
(3AHc) families of vacuum circuit breaker “caution” used in this manual indicate the
operator modules are designed to meet all degree of hazard that may be encountered
applicable ANSI, NEMA and IEEE standards. by the user. These words are defined as:
Successful application and operation of this
Danger - Indicates an imminently hazardous
equipment depends as much upon proper
situation that, if not avoided, will result in
installation and maintenance by the user as
death or serious injury.
it does upon the proper design and
fabrication by Siemens. Warning - Indicates a potentially hazardous
situation that, if not avoided, could result in
The purpose of this instruction manual is to
death or serious injury.
assist the user in developing safe and
efficient procedures for the installation, Caution - Indicates a potentially hazardous
maintenance and use of the equipment. situation that, if not avoided, may result in
minor or moderate injury.
Contact the nearest Siemens representative
if any additional information is desired. Caution (without safety alert symbol) -
Indicates a potentially hazardous situation
In this instruction manual, reference to type
that, if not avoided, may result in property
3AH includes both type 3AH3 and type 3AHc
damage.
operator modules. When information
specific to the type 3AH-compact (3AHc)
design is involved, the text will so designate.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Hazardous Procedures Field service operation and warranty

In addition to other procedures described in issues
this instruction manual as dangerous, user Siemens can provide competent, well-
personnel must adhere to the following: trained field service representatives to
provide technical guidance and advisory
1. Always work only on a de-energized
assistance for the installation, overhaul,
circuit breaker. The circuit breaker should
repair and maintenance of Siemens
be isolated, grounded and have all
equipment, processes and systems. Contact
control power removed before
regional service centers, sales offices or the
performing any tests, maintenance or
factory for details, or telephone Siemens
repair.
field service at 1-800-333-7421 or 1-423-
2. Always perform maintenance on the 262-5700 outside the U.S.
circuit breaker after the spring-charged
For medium-voltage customer service
mechanisms are discharged (except for
issues, contact Siemens at 1-800-333-7421
test of the charging mechanisms). Check
or 1-423-262-5700 outside the U.S.
to be certain that the indicator flags read
OPEN and DISCHARGED.
3. Always let an interlock device or safety
mechanism perform its function without
forcing or defeating the device.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Receiving, handling and

storage

Heavy weight.
Improper lifting or hoisting can result in death, serious injury or
property damage.
Obtain the services of a qualified rigger prior to hoisting the circuit
breaker to assure adequate safety margins in the hoisting equipment
and procedures to avoid damage.

Introduction Shipping damage claims

This portion of the instruction manual Important: The manner in which visible
covers the receiving, handling and storage shipping damage is identified by consignee
instructions for a type 3AH3 vacuum circuit prior to signing the delivery receipt can
breaker operator module. This section of the determine the outcome of any damage
instruction manual is intended to help the claim to be filed.
user identify, inspect and protect the circuit Notification to carrier within 15 days for
breaker operator module prior to its concealed damage is essential if loss
installation. resulting from unsettled claims is to be
Receiving procedure eliminated or minimized.
Make a physical inspection of the shipping 1. When the shipment arrives, note
container before removing or unpacking the whether the equipment is properly
circuit breaker operator module. protected from the elements. Note the
Check for shipment damage or indications trailer number the equipment arrived on.
of rough handling by the carrier. Check each Note also any blocking of equipment.
item against the manifest to identify any During unloading, check the actual
shortages. equipment delivered to verify it agrees
with the delivery receipt.
Accessories such as the manual charging
crank, the racking crank (if applicable) and 2. Make immediate inspection for visible
the split plug jumper (if applicable) are damage upon arrival and prior to
shipped separately. disturbing or removing packaging or
wrapping material. This should be done
prior to unloading when possible. When
total inspection cannot be made on
vehicle prior to unloading, close
inspection during unloading must be
performed and visible damage noted on
the delivery receipt. Take pictures if
possible.
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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

3. Any visible damage must be noted on the Note: Shipments are not released from the
delivery receipt and acknowledged with factory without a clear bill of lading.
the driver’s signature. The damage should Approved methods are employed for
be detailed as much as possible. It is preparation, loading, blocking and tarping
essential that a notation "possible of the equipment before it leaves the
internal damage, subject to inspection" Siemens factory. Any determination as to
be included on the delivery receipt. If the whether the equipment was properly loaded
driver will not sign the delivery receipt or properly prepared by shipper for over-the-
with the damage noted, the shipment road travel cannot be made at the
should not be signed for by the destination. If the equipment is received in a
consignee or their agent. damaged condition, this damage to the
equipment has to have occurred while en
4. Notify Siemens medium-voltage
route due to conditions beyond Siemens‘
customer service immediately of any
control. If the procedure outlined above is
damage, at 1-800-333-7421 or 1-423-
not followed by the consignee, purchaser or
262-5700 outside the U.S.
their agent, Siemens cannot be held liable
5. Arrange for a carrier inspection of the for repairs. Siemens will not be held liable
damage immediately. for repairs in any case where repair work
was performed prior to authorization from
Important: Do not move the equipment
Siemens.
from the place it was set when unloading.
Also, do not remove or disturb packaging or Handling procedure
wrapping material prior to carrier damage 1. Carefully remove the shipping carton
inspection. Equipment must be inspected by from the circuit breaker. Keep the
carrier prior to handling after receipt. This shipping pallet for later use if the circuit
eliminates loss due to claims by carrier that breaker is to be stored prior to its
the equipment was damaged or further installation.
damaged on site after unloading.
2. Inspect for concealed damage.
6. Be sure the equipment is properly Notification to carrier must take place
protected from any further damage by within 15 days to assure prompt
covering it properly after unloading. claim resolution.
7. If practical, make further inspection for 3. Each circuit breaker should be lifted
possible concealed damage while the appropriately to avoid crushing the side
carrier’s inspector is on site. If inspection panels of the circuit breaker, or
for concealed damage is not practical at damaging the primary disconnect
the time the carrier’s inspector is assemblies.
present, it must be done within 15 days
Type 3AH3 vacuum circuit breaker
of receipt of the equipment. If concealed
operator modules weigh between 165
damage is found, the carrier must again
and 408 lbs (75-185 kg), plus an
be notified and inspection made prior to
additional 100 lbs (45 kg) for packaging
taking any corrective action to repair.
and pallet. Refer to Table 13 for more
Also notify Siemens immediately at
information.
1-800-333-7421 or 1-423-262-5700
outside the U.S. Type 3AHc vacuum circuit breaker
operator modules are not furnished
8. Obtain the original carrier inspection
separately, but are supplied as a
report and forward it with a copy of the
component of a complete drawout
noted delivery receipt to Siemens.
circuit breaker. Weights and lifting
Approval must be obtained by Siemens
details are provided in the circuit breaker
from the carrier before any repair work
manuals.
can be performed.
4. The palleted circuit breaker can be
Before approval can be obtained, Siemens
moved using a properly rated fork-lift
must have the documents referenced in
vehicle. The pallets are designed for
the paragraph above. The carrier
movement by a standard fork-lift vehicle.
inspection report and/or driver’s signature
on the delivery receipt does not constitute
approval to repair.
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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 1: Front panel controls of circuit breaker and manual charging of closing spring Storage procedure
1. Whenever possible, install the circuit
breaker operator module in its assigned
switchgear enclosure or end location for
storage.
2. When the circuit breaker operator
G
module needs to be placed on its pallet
for storage, be sure the unit is securely
bolted to the pallet and covered with
polyethylene film at least 10 mils thick.
A E
Indoor storage
Whenever possible, store the circuit breaker
operator module indoors. The storage
environment must be clean, dry and free of
B F
such items as construction dust, corrosive
atmosphere, mechanical abuse and rapid
temperature variations.
C
Outdoor storage
D Outdoor storage is not recommended. When
no other option is available, the circuit
breaker operator module must be
completely covered and protected from rain,
snow, dirt and all other contaminants.
Space heating
Space heating must be used for both indoor
and outdoor storage to prevent
condensation and corrosion. When the
circuit breaker operator module is stored
outdoors, 250 watts per circuit breaker of
space heating is recommended. If the circuit
Item Description Item Description breaker operator module is stored inside the
A Manual spring-charging port E Manual close pushbutton switchgear enclosure, and the switchgear is
B CHARGED/DISCHARGED indicator F Manual open pushbutton equipped with space heaters, energize the
space heaters.
C OPEN/CLOSED indicator
G Rating plate
D Operation counter

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Installation checks and

functional tests

Hazardous voltage and high-speed moving parts.

Will cause death, serious injury and property damage.

Read instruction manuals, observe safety instructions and use qualified

personnel.

Introduction De-energizing control power in

This section provides a description of the switchgear
inspections, checks and tests to be When the circuit breaker is mounted in
performed on the circuit breaker operator switchgear, open the control-power
module only. disconnect device in the metal-clad
switchgear cubicle, outdoor circuit breaker
Inspections, checks and tests without
housing or other location.
control power
Vacuum circuit breakers are normally In metal-clad switchgear, the control-power
shipped with their primary contacts OPEN disconnect device is normally located on the
and their springs DISCHARGED. However, it secondary-device panel in the upper cell of
is critical to first verify the DISCHARGED the vertical section. The normal control-
condition of the spring-loaded mechanisms power disconnect device is a pullout-type
after de-energizing control power. fuse holder. Removal of the fuse holder
de-energizes control power to the circuit
breaker in the associated switchgear cell.
In some switchgear assemblies, a molded-
case circuit breaker or knife switch is used in
lieu of the pullout-type fuse holder. Opening
this circuit breaker or switch accomplishes
the same result: control power is
disconnected. Opening this circuit breaker
or switch accomplishes the same result:
control power is disconnected.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Spring-discharge check (refer to Figure 1) Automatic spring-charging check

Perform the spring-discharge check before The automatic spring-charging features of
removing the circuit breaker or operator the circuit breaker must be checked. Control
module from the pallet or removing it from power is required for automatic spring-
the switchgear. charging to take place.
The spring-discharge check should be Note: A temporary source of control power
performed after de-energizing control and test leads may be required if the control-
power. This check assures both the tripping power source has not been connected to the
and closing springs are fully discharged. switchgear or circuit breaker. Refer to
specific wiring information and rating label
Note: Do not perform the spring-discharge
for your circuit breaker to determine the
check if the circuit breaker is in the
voltage required and where
CONNECT position. Open the circuit breaker
the control-voltage signal should be applied.
and rack to the DISCONNECT position, and
When control power is connected to the
then perform the spring-discharge check.
circuit breaker, the closing spring should
For fixed-mounted circuit breaker
automatically charge.
applications, open the isolator switches on
the line side and on the load side of the 1. Open control-power circuit by opening
circuit breaker before performing the spring- the control-power disconnect device.
discharge check.
2. Energize (close) the control power-circuit
1. Press red trip pushbutton. disconnect.
2. Press black close pushbutton. 3. Use the close and open controls (refer to
Figure 1) to first close and then open the
3. Press red trip pushbutton again.
circuit breaker contacts. Verify contact
4. Verify spring-condition indicator shows positions visually by observing the OPEN/
DISCHARGED. CLOSED indicator on the circuit breaker.
5. Verify main contact status indicator 4. De-energize (close) the control-power by
shows OPEN. repeating Step 1. If a split-plug jumper
was used for temporary control-power
Manual-spring charging check
connections, disconnect the split-plug
1. Insert the manual-spring charging crank
jumper from the switchgear first and
into the manual-charge handle socket as
next from the circuit breaker.
shown in Figure 1. Turn the crank
clockwise (about 48 revolutions) until 5. Perform the spring discharge check
the spring condition indicator shows the again. Verify the closing springs are
closing spring is CHARGED. DISCHARGED and the primary contacts of
the circuit breaker are OPEN.
2. Repeat the spring-discharge check.
Final mechanical inspections without
3. Verify the springs are DISCHARGED and
control power
the circuit breaker primary contacts are
1. Make a final mechanical inspection of
OPEN by indicator positions.
the circuit breaker. Verify the contacts
As-found and vacuum-integrity check are in the OPEN position, and the closing
tests springs are DISCHARGED.
Perform and record the results of both the
2. Verify mechanical condition of springs.
as-found insulation test and the vacuum-
integrity check (dielectric) test. Procedures 3. Check for loose hardware.
for these tests are described in the
Maintenance section of this instruction
manual beginning on page 28.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Vacuum interrupter/
operator

Figure 2: Vacuum circuit breaker operator module

3AH vacuum circuit breaker operator 3AHc

vacuum
circuit breaker
B A
operator

N
M
T N
C

R
D
S
Q
E H P
K
B
A G M
R J F
O V
S
F C D
Q
G O
H U
P
J
I L
J
K

Item Description Item Description

A Pole head L Guide link
B Upper connection pad M Upper post insulator
Introduction
C Strut N Operator housing
The type 3AH vacuum circuit breaker
operator is intended for application in a D Vacuum interrupter O Lower post insulator
drawout truck for use in medium-voltage E Moving contact P Insulating coupler (48.0)
metal-clad switchgear and for stationary F Centering piece Q Contact pressure spring (49.0)
applications, such as the type SDV6 outdoor G Terminal clamp R Lever
distribution circuit breaker. The type 3AH
H Flexible connector S Jack shaft
circuit breaker conforms to the requirements
of ANSI/IEEE standards, including C37.20.2, I Eye bolt T Pole plate
C37.04, C37.09 and C37.010. J Pole bottom (lower pole head) U Lower connector
K Angled lever V Vehicle frame

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 4: Vacuum circuit breaker operator module This section describes the operation of each
Figure 3: Vacuum interrupter cut-
away view major subassembly as an aid in the
1
operation, installation, maintenance and
repair of the circuit breaker.
Vacuum interrupters
2 The operating principle of the vacuum
interrupter is simple. Figure 3 is a section
view of a typical vacuum interrupter. The
4
entire assembly is sealed after a vacuum is
3 established.
5
3AH3 operator mechanism
The vacuum interrupter stationary contact is
connected to the upper pole head of the
3AH vacuum circuit breaker operator circuit breaker. The vacuum interrupter
6 movable contact is connected to the pole
7 bottom and driving mechanism of the circuit
breaker.
8
3AHc operator mechanism
The vacuum interrupter stationary contact is
9
connected to the lower pole head of the
circuit breaker. The vacuum interrupter
Item Description movable contact is connected to the upper
pole head (pole bottom) and drive
Fixed contact-current
1
connection
mechanism of the circuit breaker.

2 Ceramic insulator The metal bellows provide a secure seal

3 Arc shield around the movable contact, preventing loss
of vacuum while permitting vertical motion
4 Fixed contact
of the movable contact.
5 Moving contact
When the two contacts separate, an arc is
6 Ceramic insulator
initiated that continues conduction up to
7 Metal bellows
the following current zero. At current zero,
8 Guide the arc extinguishes and any conductive
Moving contact- metal vapor that has been created by and
9
current connection supported the arc condenses on the
contacts and on the surrounding arc shield.
Contact materials and configuration are
optimized to achieve arc motion and to
minimize switching disturbances.
3AHc vacuum circuit breaker operator
Primary connections (refer to Figure 2)
Figure 2 illustrates the pad provision to
The circuit breaker includes three vacuum accept the primary connections. Each circuit
interrupters, a stored-energy operating breaker has three upper and three lower
mechanism, necessary electrical controls primary disconnect pad provisions, to allow
and interlock devices, disconnect devices to connection to the switchgear.
connect the circuit breaker to both primary
and control power (for drawout For stationary circuit breaker applications,
applications) and an operator housing. bus conductors connect directly to these
pads. Bolting hardware is M12 x 1.75 grade
In a typical installation in a drawout truck, 8. Torque M12 bolts to 52 ft-lb (70 Nm).
insulating barriers may be located between
the vacuum interrupters and along the
sides.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Phase barriers (if applicable) The energy-storing mechanism and all the
Plates of glass-polyester insulating material control and actuating devices are installed
are attached to the circuit breaker and in the operator housing. The mechanism is
provide suitable electrical insulation of the spring stored-energy type and is
between the vacuum interrupter and mechanically and electrically trip-free.
primary conductors and the cubicle.
The close-open indicator, closing spring-
Stored-energy operating mechanism charge indicator and the operation counter
The stored-energy operating mechanism of are located on the front of the operator
the circuit breaker is an integrated housing.
arrangement of springs, coils and
The control connector for the control and
mechanical devices designed to provide a
signalling cables is a multi-contact plug in
number of critical functions. The energy
most designs, although direct connection to
necessary to close and open the contacts of
the switchgear is used for certain products.
the vacuum interrupters is stored in
powerful opening and closing springs. The Circuit breaker pole (refer to Figure 2)
closing springs are normally charged The vacuum interrupter is bolted to the
automatically, but there are provisions for upper pole head and the upper pole head is
manual charging. The operating mechanism rigidly connected to the operator housing by
that controls charging, closing and tripping the post insulator. The moving contact end
functions is fully trip-free. “Trip-free” of the vacuum interrupter is stabilized
requires that the tripping function prevail against lateral forces by a centering ring on
over the closing function as specified in the pole bottom. The external forces due to
ANSI/IEEE C37.04. switching operations and the contact
pressure are absorbed by the struts.
Vacuum interrupter/operator module
The vacuum interrupter/operator module Current-path assembly (refer to Figure 2)
consists of the three poles, each with its The current-path assembly consists of the
vacuum interrupters and primary insulators, pole head, the stationary contact and the
mounted on the common operating moving contact, that is connected to the
mechanism housing. This module is shown pole bottom by a terminal clamp and a
in Figure 4. flexible connector.
Construction (Refer to Figures 1, 2, 5 and Vacuum interrupter (refer to Figure 2)
6) (3AH only) The moving-contact motion is aligned and
This description covers the type 3AH stabilized by a guide bushing. The metal
operator. The type 3AHc differs in bellows follows the travel of the contact and
arrangement but the fundamental seals the vacuum interrupter against the
discussion of operation applies. surrounding atmosphere.
Each of the circuit breaker poles are fixed to Switching operation (refer to Figures 2
the rear of the operating mechanism and 5)
housing by two cast-resin insulators. The When a closing command is initiated, the
insulators also connect to the upper and closing spring (62.0), that was previously
lower pole supports that in turn support the charged by hand or by the motor, actuates
ends of the vacuum interrupter. the moving contact through the jack shaft
(63.0), lever, contact pressure spring (49.0),
The pole supports are aluminum castings
insulating coupler (48.0) and angled lever.
(most 1,200 A, all 2,000 A and some
3,000 A), copper castings (some 3,000 A) or The forces that occur when the action of the
sheet steel (some 1,200 A). For type 3AH insulating coupler (48.0) is converted into
operators, primary disconnect stud the vertical action of the moving contact are
extensions may be attached directly to the absorbed by the guide link, that pivots on
upper and lower pole connection pads. the pole bottom and the eye bolt.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

During closing, the opening spring (64.0) Motor-operating mechanism (refer to

(refer to Figure 6) and the contact pressure Figure 5)
springs (49.0) are charged and latched by The spring-charging motor (50.4) is bolted
pawl (64.2) (refer to Figure 6). The closing to the charging mechanism (50.2) gear box
spring (62.0) (refer to Figure 5) of the installed in the operator housing. Neither
motor-operated circuit breaker is recharged the charging mechanism nor the motor
immediately after closing. require any maintenance.
In the closed state, the necessary contact Mode of operation
pressure is maintained by the contact The operating mechanism is of the stored-
pressure springs (49.0) and the atmospheric energy trip-free type. For example, the
pressure. The contact pressure spring charging of the closing spring is not
automatically compensates for arc erosion, automatically followed by the contacts
which is very small. changing position, and tripping function
prevails over the closing function.
When a opening command is given, the
energy stored in the opening and contact When the stored-energy mechanism has
pressure springs (49.0) is released by pawl been charged, the mechanism is ready for a
(64.2) (refer to Figure 6). closing operation at any time.
The opening sequence is similar to the The mechanical energy for carrying out an
closing sequence. The residual force of the “Open-Close-Open” sequence for auto-
opening spring maintains the moving reclosing duty is stored in the closing and
contacts in the open position. opening springs.
Operating mechanism Charging
The operating mechanism is comprised of The details of the closing spring charging
the mechanical and electrical components mechanism are shown in Figure 5. The
required to: charging shaft is supported in the charging
mechanism gear box (50.2), but is not
1. Charge the closing spring with sufficient
coupled mechanically with the charging
potential energy to close the circuit
mechanism. Fitted to it are the crank (62.2)
breaker and to store opening energy in
at one end, and the cam (62.3), together
the opening and contact pressure
with lever (62.5), at the other.
springs.
2. Mechanisms to release closing and
opening actions.
3. Means of transmitting force and motion
to each of the three vacuum
interrupters.
4. Operate all these functions
automatically through an electrical
charging motor, cutout switches, an
anti-pump relay, a close coil, an open
coil and an auxiliary switch.
5. Provide indication of the circuit breaker
status (OPEN/CLOSED), spring condition
(CHARGED/DISCHARGED) and number of
operations.
Construction
The essential parts of the operating
mechanism are shown in Figures 5 and 6.
The control and sequence of operation of
the mechanism is described in Figure 7.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 5: Stored-energy operating mechanism (circuit breaker shown in OPEN position) (straight linkage shown)

62.5
55.2 62.3

62.1 50.3
62.5.2
62.2
68.0
53.0
50.5 62.6
50.2

55.1
53.1

62.0 54.1
50.4.1

55.0 54.0

50.4
64.0
68.1

58.0

63.0 63.1

63.5
61.8
59.0
60.0
Item Description Item Description Footnote:
50.2 Charging mechanism gear box 62.1 Charging shaft For certain applications, the straight
1.

trip coupling rod (62.8) is replaced

50.3 Charging flange 62.2 Crank by a collapsible trip-free coupling
50.3.1 Driver (not visible) 62.3 Cam disc system, illustrated in Figures 6-10.
50.4 Spring charging motor 88.0 62.5 Lever
50.4.1 Limit switches 62.5.1 Pawl roller (not visible)
50.5 Manual spring-charging port 62.5.2 Close latch pawl
53.0 Close pushbutton 62.6 Driver lever
53.1 Close coil 52SRC 62.8 Straight coupling rod1
54.0 Open pushbutton 62.8.1 Spring return latch (not shown)1
54.1 Trip coil 52T 62.8.3 Trip-free coupling lever1
55.0 Closing spring-charge indicator 63.0 Jack shaft
55.1 Linkage 63.1 Lever phase C
55.2 Control lever 63.5 Lever phase B
58.0 CLOSED/OPEN indicator 63.7 Lever phase A
59.0 Operations counter 64.0 Opening spring
60.0 Operator housing 68.0 Auxiliary switch
61.8 Shock absorber
68.1 Auxiliary switch link
62.0 Closing spring

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 6: Stored-energy operating mechanism (circuit breaker shown in CLOSED position) Closing (refer to Figures 5, 7-10)
(Drawout trip-free linkage shown) If the circuit breaker is to be closed
manually, the closing spring is released by
Item Description
pressing the Close button (53.0). In the case
54.0 Open pushbutton of remote electrical control, the close coil
62.8 Trip-free coupling rod1 62.8.1 52SRC (53.1) unlatches the closing spring
62.8.1 Spring-return latch1 (62.0).
Trip-free coupling link 62.8.2 As the closing spring discharges, the
62.8.2
(draw bar)1 62.8 charging shaft (62.1) is turned by crank
64.0
64.0 Opening spring 54.0 (62.2).
64.2 Trip-latch pawl (not visible) The cam disc (62.3) at the other end of the
64.3 Lever charging shaft actuates the drive lever
64.3.1 Pawl roller 64.3.1 (62.6), with the result that jack shaft (63.0)
is turned by lever (63.5) via the coupling rod
64.3 (62.8). At the same time, the levers (63.1),
(63.5) and (63.7) fixed on the jack shaft
operate the three insulated couplers (48.0)
Footnote: (refer to Figure 2) for the circuit breaker
1.
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is
poles. Lever (63.7) changes the OPEN/CLOSE
replaced with a straight coupling rod, and other parts associated with drawout
interlocking are eliminated. indicator (58.0) over to CLOSED. Lever
(63.5) charges the opening spring (64.0)
during closing, and the circuit breaker is
When the charging mechanism is actuated latched in the closed position by lever (64.3)
by hand with a hand crank (refer to Figures with pawl roller (64.3.1) and by pawl (64.2).
12 and 13) or by a motor (50.4), the flange Lever (63.1) actuates the auxiliary switch
(50.3) turns until the driver (50.3.1) locates (68.0) through the linkage (68.1).
itself in the cutaway part of the cam disc
The crank (62.2) on the charging shaft
(62.3), thus causing the charging shaft to
(62.1) moves the linkage (55.1) by acting
follow. The crank (62.2) charges the closing
on the control lever (55.2). The closing
spring (62.0). When the closing spring has
spring charged indication is thus canceled,
been fully charged, the crank actuates the
and the limit switches (50.4.1) switch in the
linkage (55.1) via the control lever (55.2)
control supply to cause the closing spring to
for the closing spring CHARGED indicator
recharge immediately.
(55.0), and actuates the limit switches
(50.4.1) for interrupting the motor supply. Trip-free operation
At the same time, the lever (62.5) at the (refer to Figures 5 and 6)
other end of the charging shaft is securely Trip-free for all drawout circuit breakers
locked by the close latch pawl (62.5.2). and some fixed-mounted circuit breakers
When the closing spring is being charged, The trip coupling rod (62.8 together with
the cam disc (62.3) follows along, and it is 62.8.1 and 62.8.2) permits the immediate
brought into position for closing when the de-coupling of the drive lever (62.6) and the
closing spring is fully charged. jack shaft (63.0) to override closing action
by trip command or by means of the racking
interlocks.
The trip-free coupling rod (62.8) forms a
link between the drive lever (62.6) and the
jack shaft (63.0). The rigidity of this link
depends upon a spring-return latch (62.8.1)
carried within the coupling rod. The latch
pivots within the coupling rod and is
normally positioned to maintain the rigidity
of the coupling rod.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Trip-free coupling link (62.8.2) and trip-free Manual operation

coupling lever (62.8.3) cause the spring- Electrically operated vacuum circuit breakers
return latch position to be dependent upon can be operated manually if the control
the normal tripping components and the supply should fail.
racking interlock (if applicable). Thus,
Manually charging the closing spring
whenever a trip command is applied or the
(refer to Figures 13 and 14)
circuit breaker is not in the fully CONNECT
Insert the hand crank (50.0) with the over
or TEST position (for drawout applications),
running coupling pushed forward (50.6)
the trip-free coupling rod is no longer rigid,
through the opening (50.1) onto hand crank
effectively decoupling the drive lever and
coupling (50.5) and turn it clockwise (about
jack shaft. Under these conditions the
48 revolutions) until the closing-spring
vacuum interrupter contacts cannot be
indicator (55.0) shows CHARGED. The hand
closed.
crank is coupled with the charging
Trip-free for the type SDV6 outdoor distri- mechanism via an over-running coupling;
bution circuit breaker and some fixed- thus the operator is not exposed to any risk
mounted circuit breakers should the control supply be restored during
For the type SDV6 outdoor distribution manual charging.
circuit breaker and some other fixed-
mounted circuit breakers, the drawout trip-
free linkage (refer to Figures 7-10) is
replaced with simplified linkage. The trip-
free coupling rod (62.8) is replaced with a
straight coupling rod (refer to Figure 5), and
other parts associated with drawout The special hand crank automatically disengages
interlocking are eliminated. if the spring-charging motor operates. In order to
avoid injuries as a result of the motor suddenly
The parts modified or eliminated are noted
starting up, the circuit breaker spring must only
in the relevant figures. In these circuit be charged manually with the special hand crank
breakers, the trip-free function is (50.0).
accomplished by blocking the movement of
the close latch pawl (62.5.2) when the
manual trip pushbutton is actuated.
Opening (refer to Figure 5)
If the circuit breaker is to be opened
manually, the opening spring (64.0) is
released by pressing the OPEN pushbutton
(54.0). In the case of an electrical command
being given, the trip coil 52T (54.1)
Manual closing (refer to Figure 6)
unlatches the opening spring (64.0).
Press the close button (53.0). The CLOSE/
The opening spring (64.0) turns the jack OPEN indicator (58.0) will then display
shaft (63.0) via lever (63.5); the sequence CLOSED and the closing spring condition
being similar to that for closing. indicator (55.0) will now read DISCHARGED.

Rapid auto-reclosing Manual opening (refer to Figure 6)

Since the closing spring is automatically The opening spring (64.0) is charged during
recharged by the motor operating closing. To open the circuit breaker, press
mechanism when the circuit breaker has the Open pushbutton (54.0) and OPEN will
closed, the operating mechanism is capable be displayed by indicator (58.0).
of an “Open-Close-Open” duty cycle as
required for rapid auto-reclosing.
The circuit breaker is suitable for use in
applications with a rated reclosing-time
interval of 0.3 seconds, per ANSI/IEEE
C37.04.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 7: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED

Item Description
48.0 Insulating coupler
50.3 Charging flange
50.3.1 Driver
53.0 Close pushbutton
62.5.1†
62.5 53.1 Close coil 52SRC
62.1 54.0 Open pushbutton
62.3† 50.3
54.1 Trip coil 52T
62.2†
50.3.1 62.1 Charging shaft
62.2 Crank
62.5.2†
53.0 62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller
64.5* 62.6
53.1 62.2.2 62.5.2 Close latch pawl

64.2.2 62.6 Drive lever

64.0* 62.8 Trip-free coupling rod

62.8.1
62.8.1 Spring-return latch
64.2.1† 62.8.2 Trip-free coupling link (draw bar)

62.8.3† 54.0 62.8.3 Trip-free coupling lever

62.8.5 Push rod and cam assembly
62.8.2† 62.8.6 Interlock lever push rod
62.8* 62.8.7 Interlock lever actuator
64.2* 62.8.8 Trip-free actuator
64.3.1*
63.5* 63.0 Jack shaft
62.8.5† 63.1 Lever - phase C
63.5 Lever - phase B
64.5*
63.7 Lever - phase A
63.0*
64.0 Opening spring
63.7 62.8.7†
* 63.5* 64.2 Trip-latch pawl
63.5 62.8.6†
63.1 64.2.1 Trip-latch pin

62.8.8 64.2.2 Latching pawl-release lever

64.3 Lever
64.3.1 Jack-shaft pawl
64.5 Opening-spring shaft

Footnotes:
* Items moved from position shown in Figure 9: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
CLOSED, closing spring DISCHARGED on trip operation.
† Items moved from position shown in Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN,
closing spring DISCHARGED on closed spring discharge operation.
1.
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other parts
associated with drawout interlocking are eliminated.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED
.

Item Description
48.0 Insulating coupler
50.3 Charging flange
50.3.1 Driver
53.0 Close pushbutton
53.1 Close coil 52SRC
54.0 Open pushbutton 62.2†
50.3.1†
54.1 Trip coil 52T
62.1† 62.3†
62.1 Charging shaft 50.3†

62.2 Crank 62.5†

62.5.1†
62.2.2 Closing-spring mounting 62.2.2†
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller
62.5.2 Close latch pawl
62.6 Drive lever 64.5*
62.8 Trip-free coupling rod
62.8.1 Spring-return latch
62.8.2 Trip-free coupling link (draw bar)
62.8.3 Trip-free coupling lever 54.1*
62.8.5 Push rod and cam assembly
62.8.6 Interlock lever push rod
62.8.7 Interlock lever actuator
62.8.8 Trip-free actuator 62.8*
63.0 Jack shaft 64.2*
64.3*
63.1 Lever - phase C
63.5*
63.5 Lever - phase B
63.7 Lever - phase A
64.0 Opening spring
64.2 Trip-latch pawl 63.0*

64.2.1 Trip-latch pin 64.5* 63.7*

48.0* 63.5*
64.2.2 Latching pawl-release lever 63.1*
64.3 Lever
64.3.1 Jack-shaft pawl
64.5 Opening-spring shaft

Footnotes:
* Items moved from position shown in Figure 10: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
CLOSED, closing spring CHARGED on trip operation.
† Items moved from position shown in Figure 7: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
OPEN, closing spring DISCHARGED on closed spring discharge operation.
1.
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other parts
associated with drawout interlocking are eliminated.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 9: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism CLOSED, closing spring DISCHARGED

Item Description
48.0 Insulating coupler
53.0 Close pushbutton
53.1 Close coil 52SRC
62.1 Charging shaft
62.2 Crank
62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1
62.5.1 Pawl roller
62.5 62.5.2 Close latch pawl
62.1 62.6 Driver lever

62.2 62.8 Trip-free coupling rod

63.0 Jack shaft
62.5.2 62.3
63.1 Lever - phase C
53.0
63.5 Lever - phase B
63.7 Lever - phase A
64.5 Opening-spring shaft
64.5 62.6
53.1
62.2.2

62.8
64.5

63.7
63.5
63.1

63.0
48.0
63.5

Footnotes:
* Numbered items moved from position shown in Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown)
mechanism OPEN, closing spring DISCHARGED.
1.
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other parts
associated with drawout interlocking are eliminated.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 10: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism CLOSED, closing spring CHARGED

Item Description
50.3 Charging flange
50.3.1 Driver
62.1 Charging shaft
62.2 Crank
62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller

62.2
50.3.1
62.3
62.1
62.5 50.3
62.5.1
62.2.2

Footnotes:
* Numbered items moved from position shown in Figure 9: Operating mechanism section diagram (drawout trip-free linkage shown)
mechanism CLOSED, closing spring DISCHARGED.
1.
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other parts
associated with drawout interlocking are eliminated.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 11: Operator sequential operation diagram

Closing Closed
voltage applied. Anti-pumping feature (52Y) assures a continuously applied closing command does not cause
the circuit breaker to reclose automatically after it has tripped out on a fault.

Undervoltage device Spring-charge motor Continuous

27 picks up. (88.0) energized. closing command.

Closing spring is
fully charged.
Close coil (52SRC)
unlatches the closing
LS21 and LS22 LS9 closes close
L3 opens in series LS41 closes to spring and the circuit
operate to circuit only when
with anti-pump signal closing spring breaker closes.
de-energize spring- closing spring is
relay (52Y). is charged.
charging motor. fully charged.
Motor cutoff switches
LS21, LS22 and LS3 are
Circuit Circuit closed because the
breaker breaker closing spring is
No action! Open is closed. Close coil is
is open. discharged.
52b in series with Closing actuated through
close coil (52SRC) command the closed 52b
blocks closing when contacts and the Before the spring-
spring-release. two normally closed charge motor has
Closing contacts of the anti- recharged the closing
spring is pump relay (52Y). spring and opened LS3,
not charged. anti-pump relay (52Y)
No action! Anti- picks up and seals in.
pump relay (52Y)
The closing spring is The opening spring
picks up through
unlatched. is charged. The anti-pump relay
the closed LS3
contact and opens. (52Y) opens two
contacts in series with
LS21 and LS22 close the close coil (52SRC).
52a contacts in
Circuit breaker to energize motor
series with the trip
auxiliary contacts The circuit breaker (88). LS3 closes and
coil (52T) close to
52a and 52b change closes. LS9 opens to cancel The close coil (52SRC)
enable a trip
state. closing spring is now blocked and
operation.
signal. cannot be activated
until springs are fully-
Rapid auto-reclosing. The closing spring is automatically recharged as described above. charged and close
Therefore, when the circuit breaker is closed both of its springs are charged. The closing command is removed.
spring charges the opening spring during closing. As a result, the circuit breaker is capable of
an O-0.3s-CO-3 min-CO operating cycle. The dashed line shows the operating sequence
Footnote:
initiated by the closing command. 1.
Optional items.
Tripping
Trip
command.

Undervoltage device (27) is Secondary shunt-

Trip coil (52T) can Undervoltage device (27) is
activated by closing NO contact, release (dual-trip)
only be activated activated by opening a NC
shorting the 27 coil. The NO function activated
when in series contact in series with 27 or by
contact is only effective with the by remote trip
connected 52a loss or reduction of tripping
circuit breaker closed. Resistor command contact
contact is closed. voltage.1
required.1 NO.1

Trip coil (52T) Undervoltage device Secondary release

unlatches the 27 unlatches the unlatches the
opening spring. opening spring.1 opening spring.1

Circuit breaker trips.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 12: Use of manual spring-operation crank

The schematic shown in Figure 14 is
intended to aid in understanding the
mechanism operation discussed in this
instruction manual. It shows a drawout 50.0 50.5 53.0
circuit breaker as an example. Refer to the
schematic diagram furnished with your
circuit breaker for specific information.
Close coil (52SRC)
The close coil (3AY1510) is a standard
component of the circuit breaker that is 55.0
used to unlatch the stored energy of the 54.0
closing spring and thus close the circuit
breaker electrically. It is available for either
ac or dc operation. After completion of a
closing operation, the close coil is
de-energized internally. If operated with ac
voltage, a rectifier is installed in the circuit
breaker.
Trip coil (52T) Item Description
The trip coil (3AY1510) is a standard 50.0 Hand crank
component of the circuit breaker. The 50.5 Manual spring-charging port
electrically supplied tripping signal is passed
53.0 Manual CLOSE pushbutton
on to the trip-latching mechanism by means
of a direct action solenoid armature and the 54.0 Manual OPEN (TRIP)) pushbutton
circuit breaker is thus opened. It is available 55.0 CHARGED/DISCHARGED indicator
for either ac or dc operation. After
completion of an opening operation, the
trip coil is de-energized internally. If Figure 13: Use of manual spring-charging crank
operated with ac voltage, a rectifier is
installed in the circuit breaker.

50.5

50.6

50.0

Item Description
50.0 Hand crank
50.5 Manual spring-charging port
50.6 Over-running coupling

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 14: Typical elementary diagram

(+)
01
01 T
C

SD16 SD13

W 21 G R
LS21 41
22 52b
42
SD3 SD4 SD1
22 21 14
Motor 88 52Y LS3 52Y
21 22 13
13 31 24
LS41 31 52b 52a
DC supply 14 52Y 32 23
21 32
LS22
22 A1 A1 A1
52SRC 52Y 52T
22 22 A2 A2 SD14 A2
MI1 MI2 34
21 21 13 LS9
52a
33
TB 14
1 SD2
2
3
4
5
SD15 6

(-)

SD11 SD9 SD7 SD5

54 64 91 101 74 84 111 121

52a 52a 52b 52b 52a 52a 52b 52b
53 63 92 102 73 83 112 122
SD12 SD10 SD8 SD6

Standard:
Fuses in close circuit. Slugs in trip circuit (fuses optional).

Shown with springs discharged, trip-latch reset, circuit breaker open, connect or withdrawn position.

Item Description Item Description

88.0 Spring-charging motor LS Spring-charged switch
52a Auxiliary switch is open when circuit breaker is open MI1, M12 Mechanical interlock
52b Auxiliary switch is closed when circuit breaker is open 01/C Control switch (CLOSE)
52SRC Spring-release coil (CLOSE) 01/T Control switch (TRIP)
52T Shunt-trip coil G Green indicating light (TRIP)
R Red indicating light (CLOSED)
52Y Closing relay (anti-pump)
W White indicating light (spring-charged)

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Indirect releases - secondary shunt Figure 15: Construction of secondary shunt release (shown charged)
release (dual trip) (52T1) or undervoltage
(27.0)
The indirect release provides for the
conversion of modest control signals into
33.0
powerful mechanical-energy impulses. It is 23.0
primarily used to open medium-voltage 31.0
25.0 27.0
circuit breakers while functioning as a 21.0
secondary shunt-release (dual trip) or 11.0
13.0 7.0
undervoltage device.
9.0 1.0
These releases are mechanical energy- 15.0
storage devices. Their internal springs are
charged as a consequence of the circuit
6.0
breaker mechanism operation. This energy
is released upon application or removal (as 3.0
appropriate) of applicable control voltages
(refer to Figures 15, 16 and 17).
Item Description Item Description
The secondary shunt-release and 1.0 Magnet core 15.0 Tripping pin
undervoltage release mounts to the
3.0 Housing 21.0 Locking pin
immediate right of the trip coil (54.1).
6.0 Mounting holes 23.0 Striker pin
Secondary shunt-release (52T1) (refer to 7.0 Magnet coil 25.0 Latch
Figure 15)
9.0 Magnet armature 27.0 Spring
A secondary shunt-release (extra-trip coil)
(3AX1101) is used for electrical opening of 11.0 Tension spring 31.0 Striker-pin spring
the circuit breaker by protective relays or 13.0 Adjusting screw (factory set) for 11.0 33.0 Terminal block
manual control devices when more than
one trip coil is required. The second trip coil
Figure 16: Latch details (shown charged)
is generally connected to a separate
auxiliary supply (dc or ac) from the control
supply used for the normal trip coil.
Undervoltage release (27.0) (refer to
Figures 16 and 17) 29.0
The undervoltage release (3AX1103) is used
for continuous monitoring of the tripping
supply voltage. If this supply voltage falls
excessively, the undervoltage release will 23.0
provide for automatic tripping of the circuit
breaker.
The undervoltage device may be used for
manual or relay tripping by employing a 25.0 27.0
contact in series with undervoltage device
holding coil. Relay tripping may also be
achieved by employing a normally open 21.0
contact in parallel with the holding coil. If
this scheme is used, a resistor must be
provided to limit current when the normally
open contact is closed.
Secondary shunt and undervoltage releases Item Description Item Description
are available for all standard ANSI/IEEE 21.0 Locking pin 25.0 Latch
control voltages. 23.0 Striker pin Undervoltage enable/disable set-
29.0
25.0 Latch ting screw (undervoltage only)

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 17: Undervoltage lock/operate selection Construction and mode of operation of

secondary shunt-release and
undervoltage release (refer to Figures 15,
16 and 17)
Position A: locked (disabled)
The release consists of a spring-power
stored-energy mechanism, a latching device
and an electromagnet.

A 29.0 These elements are accommodated side by

23.0 side in a housing (3.0), with a detachable
B cover and three through-holes (5.0) for
fastening screws. The supply leads for the
trip coil are connected to a terminal block
Position B: unlocked (enabled)
(33.0).
(operating position)
The energy-storing mechanism consists of
Item Description the striker pin (23.0) and its operating
23.0 Striker pin spring (31.0), which is mostly located inside
Undervoltage A the striker pin (23.0). When the spring is
enable/ 23.0 compressed, the striker pin is held by a latch
29.0 B
disable 29.0 (25.0), whose sloping face is forced against
setting screw the appropriately shaped striker pin (23.0)
by spring (27.0). The other end of the latch
(25.0) is supported by a partly milled
Cancel the lock for the undervoltage
locking pin (21.0), pivoted in the cover
release by shifting the locking screw
(29.0) from A (disable) to B (enable). sheets of the magnet armature (9.0). The
armature (9.0) is pivoted in front of the
poles of the U-shaped magnet core, (1.0)
and is pulled away from it by the tension
Figure 18: Capacitor-trip device spring (11.0).
If the magnet coil (7.0) of the secondary
shunt release 3AX1101 is energized by a trip
signal, or if the tripping pin (15.0) is
01
mechanically actuated, magnet armature
T
(9.0) is swung against the pole faces. When
this happens, the latch (25.0) loses its
SD5 support and releases the striker pin (23.0)
that is forced out by the spring (31.0).

24 On the undervoltage release 3AX1103, the

52a latch (25.0) is held by the locking pin (21.0)
23 as long as the armature (9.0) is energized. If
120 or 240 Vac Capacitor the circuit of the magnet coil (7.0) is
A1 (+)
supply interrupted, the armature (9.0) drops off,
52T 1 thus causing the latch (25.0) to lose its
(-)
A2 Resistor support and release the striker pin (23.0).
34 2
52a
(+) Following every tripping operation, the
33
striker pin (23.0) must be reset to its normal
Rectifier
position by loading the spring (31.0). This
(-)
takes place automatically via the operating
Capacitor trip
mechanism of the circuit breaker.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Since the striker pin of the undervoltage Shock absorber

release 3AX1103 is latched only when the Circuit breakers are equipped with a
armature is energized, the undervoltage hydraulic shock absorber (61.8) (refer to
release is provided with a screw (29.0), for Figure 5). The purpose of this shock
locking the striker pin (23.0) in the normal absorber is to limit overtravel and rebound
position for adjusting purposes or for of the vacuum interrupter movable contacts
carrying out trial operations during circuit during the conclusion of an opening
breaker servicing. Position A (locked) operation. The shock absorber action affects
disables the undervoltage release. Position B only the end of an opening operation.
(unlocked) is the normal operating position.
Auxiliary switch (52a/b)
Capacitor trip device Figure 6 shows the circuit breaker mounted
The capacitor trip device is an auxiliary auxiliary switch (68.0). This switch provides
tripping option providing a short-term auxiliary contacts for control of circuit
means of storing adequate electrical energy breaker closing and opening functions.
to ensure circuit breaker tripping. If Contacts are available for use in relaying
provided, a capacitor trip device must be and external logic circuits. This switch is
located on the drawout truck or in the driven by linkage (68.1) connected to the
stationary circuit breaker enclosure, as jack shaft (63.0). The auxiliary switch
space is not available inside the type 3AH contains both “b” (normally Closed) and “a”
operator housing. (normally Open) contacts. When the circuit
breaker is open, the “b” contacts are closed
This device is applied in circuit breaker
and the “a” contacts are open.
installations lacking independent auxiliary
control power or station battery. In such Spring-charging motor (88.0)
installations, control power is usually Spring-charging motors (50.4) (refer to
derived from the primary source. In the Figure 5) are available for either ac or dc
event of a primary ac source fault or operation. If operated with ac voltage, a
disturbance the capacitor trip device will rectifier is installed in the circuit breaker.
provide short-term tripping energy for
circuit breaker opening due to protective
relay operation or operation of a circuit
breaker control switch.
The capacitor trip converts 120 or 240 Vac
control voltage to a dc full-wave voltage
that is used to charge a large capacitor to
the peak of the converted wave (refer to
Figure 18).

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Maintenance

Hazardous voltage and high-speed moving parts.

Will cause death, serious injury and property damage.

De-energize before working on this equipment.

Read instruction manuals, observe safety instructions and use qualified

personnel.

Introduction and maintenance intervals Regardless of the length of the maintenance

Periodic inspections and maintenance are and lubrication interval, Siemens
essential to safe and reliable operation of recommends that circuit breakers should be
the circuit breaker operator module. inspected and exercised annually.
When circuit breakers are operated under For the safety of maintenance personnel as
“usual service conditions,” maintenance and well as others who might be exposed to
lubrication are recommended at ten-year hazards associated with maintenance
intervals (five-year intervals for the type activities, the safety related work practices
SDV6 outdoor distribution circuit breaker) or of NFPA 70E, chapters 1 and 2, should
at the number of operations indicated in always be followed when working on
Table 2. “Usual” and “unusual” service electrical equipment.
conditions for medium-voltage metal-clad
Maintenance personnel should be trained in
switchgear (includes circuit breaker module)
the safety practices, procedures and
are defined in ANSI/IEEE C37.20.2, ANSI/
requirements that pertain to their respective
IEEE C37.04 and ANSI/IEEE C37.010.
job assignments.
Generally, “usual service conditions” are
defined as an environment where the This instruction manual should be reviewed
equipment is not exposed to excessive dust, and retained in a location readily accessible
acid fumes, damaging chemicals, salt air, for reference during maintenance of this
rapid or frequent changes in temperature, equipment.
vibration, high humidity and extreme
The user must establish a periodic
temperatures.
maintenance program to ensure trouble-free
The definition of “usual service conditions” and safe operation. The frequency of
is subject to a variety of interpretations. inspection, periodic cleaning and a
Because of this, you are best served by preventive maintenance schedule will
adjusting maintenance and lubrication depend upon the operation conditions.
intervals based on your experience with the NFPA publication 70B, “Electrical equipment
equipment in the actual service maintenance” may be used as a guide to
environment. establish such a program.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Failure to maintain the equipment can result in death, serious injury, property damage or product
failure, and can prevent successful functioning of connected apparatus.

The instructions contained herein should be carefully reviewed, understood and followed.

The maintenance tasks in Table 1 must be performed regularly.

Note: A preventive maintenance program is Recommended maintenance and

not intended to cover reconditioning or lubrication
major repair, but should be designed to Periodic maintenance and lubrication should
reveal, if possible, the need for such actions include all the tasks shown in Table 1.
in time to prevent malfunctions during Recommended procedures for each of the
operation. listed tasks are provided in this section of
the instruction manual.
Recommended hand tools
Metric hardware is used on these circuit The list of tasks in Table 1 does not
breakers. represent an exhaustive survey of
maintenance steps necessary to ensure safe
The following list of hand tools describes
operation of the equipment. Particular
those normally used in disassembly and
applications may require further procedures.
re-assembly procedures:
Should further information be desired or
Open-end wrenches: 7, 8, 10, 13, 17, 19 should particular problems arise that are not
and 24 mm covered sufficiently for the User’s purposes,
the matter should be referred to the local
Open-end wrench: 55 mm used to
Siemens sales office.
exchange shock absorber (Quantity: two
pieces are required for the task) Checks of the primary power path
The primary power path consists of the
Sockets: 7, 8, 10, 13 and 17 mm
three vacuum interrupters, the three upper
Socket: 36 mm (used for replacing post and the three lower primary disconnects
insulators) (drawout only) or bus connections
(stationary only). These components are
Deep sockets: 19 and 24 mm
checked for cleanliness and condition. The
Hex keys: 5, 6, 8 and 10 mm vacuum interrupters are also checked for
vacuum integrity.
Torque wrench: 0-150 Nm
(0-100 ft-lbs) Some test engineers prefer to perform the
contact-erosion check during the manual
Screwdrivers: 0.032 x 1/4 in wide and
spring-charging check of the operator, since
0.055 x 7/16 in wide
charging of the springs is necessary to place
Pliers the contacts in the CLOSED position.
Light hammer Also, the vacuum-integrity check is usually
performed in conjunction with the high-
Dental mirror
potential tests.
Flashlight
These instructions assume these tests
Drift pins: 1/8, 3/16 and 1/4 in (contact-erosion/manual spring-charging
check and vacuum-integrity/high-potential
Retaining ring plier (external type, tip
tests) will be combined as described.
diameter 0.038 in).

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

The use of unauthorized parts in the repair of the equipment, or tampering by unqualified personnel
can result in hazardous conditions, that can result in death, serious injury or property damage.

Follow all safety instructions contained herein.

Table 1: Maintenance tasks Cleanliness check

Figure 2 is a side view of the circuit breaker
Inspection items and tests
with the insulating barriers removed (if
Primary-power path checks furnished) to show the vacuum interrupter,
Cleanliness check and the upper and lower connection pads.

Inspection of flexible connectors All of these components must be clean and

Stored-energy operator-mechanism checks
free of dirt or any foreign objects. Use a dry
lint-free cloth. For stubborn dirt, use a clean
Maintenance and lubrication cloth dipped in isopropyl alcohol (except for
Fastener check the vacuum interrupters). For stubborn dirt
on a vacuum interrupter use a cloth and
Manual spring-charging check
warm water and a small amount of mild
Contact-erosion check liquid-household detergent as a cleaning
Electrical-control checks agent. Dry thoroughly using a dry lint-free
cloth.
Wiring and terminals checks

Secondary-disconnect check (drawout only) Inspection of flexible connectors

Inspect the flexible connectors that connect
Automatic spring-charging check
the bottom movable contacts of the vacuum
Electrical close and trip check interrupters to the lower connection pad for
Vacuum-integrity check tightness and absence of mechanical
damage, burning or pitting.
High-potential test
Insulation test Checks of the stored-energy operator
Contact-resistance test
mechanism
The stored-energy operator checks are
Inspection and cleaning of circuit breaker
divided into mechanical and electrical
insulation
checks for simplicity and better
Functional tests organization. This first series of checks
determine if the basic mechanism is clean,
lubricated and operates smoothly without
control power. The contact-erosion check of
the vacuum interrupter is also performed
during these tasks.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Maintenance and lubrication Lubricants composed of ester oils and

Table 2 gives the recommended lithium thickeners will generally be
maintenance intervals for circuit breakers. compatible.
These intervals assume that the circuit
For all lubrication (except electrical
breaker is operated under “usual service
moving or sliding surfaces), use one of
conditions” as discussed in ANSI/IEEE
the following:
C37.20.2 (for drawout circuit breakers) or
ANSI/IEEE C37.04 and elaborated in ANSI/ Klüber Isoflex Topas L32
IEEE C37.010 (for outdoor distribution (part 3AX11333H)
circuit breakers). The maintenance and
Klüber Isoflex Topas L32N (spray)
lubrication interval is the lesser of the
(part 15-172-879-201).
number of closing operations or the time
interval since last maintenance. Source:
Klüber Isoflex Topas L32 or L32N:
Klüber Lubrication North America L.P.
Table 2: Maintenance and lubrication schedule
www.klueber.com.
Number of years/closing Fastener check
Circuit
operations (whichever comes Inspect all fasteners for tightness. Both
breaker type
first) locknuts and retaining rings are used.
SDV6 5 years/10,000 operations Replace any fasteners that appear to have
been frequently removed and replaced.
All others 10 years/10,000 operations
Manual spring-charging and contact-
erosion checks
Perform the manual spring-charging check
The vacuum interrupter operator contained in the section describing the
mechanism is shown in Figure 19, with the installation check and initial functional tests
front cover removed to show construction (refer to pages 9-10). The key steps of this
details. Both the opening spring and the procedure are repeated here:
closing spring are shown. The movable end
of the closing spring is connected to a crank 1. Insert the hand-charging crank into the
arm. The movable end of the opening spring manual-charge socket at the front of the
is connected to the jack shaft by a pull rod. operator control panel. Turn the crank
clockwise (about 48 revolutions) to
Clean the entire stored-energy operator charge the closing spring. Continue
mechanism with a dry, lint-free cloth. cranking until the CHARGED flag appears
Check all components for evidence of in the window of the spring indicator.
excessive wear. Place special attention upon 2. Press the Close (black) pushbutton. The
the closing spring-crank and the insulating contact-position indicator on the
couplers and linkages. operator control-panel should indicate
Lubricate all non-electrical moving or sliding that the circuit breaker contacts are
surfaces with a light coat of synthetic grease CLOSED.
or oil. 3. Perform the contact-erosion check.
Contact erosion occurs when high fault-
currents are interrupted. Determination
of acceptable contact condition is
checked by the visibility of the white
contact-erosion mark shown in Figure
20. The white contact-erosion mark is
located on the movable stem of the
vacuum interrupter, near the plastic
guide-bushing.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 19: Operator mechanism lubrication

Klüber L32 or Klüber L32N

Typical for all three-phases

Figure 20: Operator mechanism pole unit lubrication

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

High-speed moving parts.

Can result in serious injury.

Tripping spring is charged. If trip latch is moved, the stored-energy springs

will discharge rapidly.

Stay clear of circuit breaker components that are subject to sudden, high-
speed movement.

Figure 21: Contact-erosion check mark dot circled in The contact-erosion check procedure is:
orange (shown with circuit breaker OPEN)
a) Be sure the circuit breaker primary
contacts are CLOSED.
b) Observe the white contact-erosion
mark (refer to Figure 20) of each pole.
When any part of the white contact-
erosion mark is visible, contact wear
is within acceptable limits.
4. Press the red Open pushbutton after
completing the contact-erosion check.
Visually verify the Discharged condition
of the closing spring and that the circuit
breaker contacts are OPEN.
5. Press the black Close pushbutton.
Nothing should happen. The manual-
spring check should demonstrate
smooth operation of the operating
mechanism.
Electrical control checks
The electrical controls of the circuit breaker
should be checked during inspections to
verify absence of any mechanical damage,
and proper operation of the automatic
spring-charging and Close and Trip circuits.
Unless otherwise noted, all of these tests
are performed without any control power
applied to the circuit breaker.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Hazardous voltage and high-speed moving parts.

Will cause death, serious injury and property damage.

De-energize before working on this equipment.

Read instruction manuals, observe safety instructions and use qualified

personnel.

Check of the wiring and terminals Electrical close and trip check (control
1. Physically check all of the circuit breaker power required)
wiring for evidence of abrasion, cuts, A check of the circuit breaker control circuits
burning or mechanical damage. shall be performed. This check is made with
the circuit breaker energized by control
2. Check all terminals to be certain they are
power either from the switchgear or an
solidly attached to their respective
external control-power source.
device.
1. Once the circuit breaker springs are
Automatic spring-charging check (control
charged, move the switchgear-mounted
power required)
Close/Trip switch to the Close position.
Repeat the automatic spring-charging check
Verify by both the sound of the circuit
described in the section describing the
breaker closing and by the main contact
installation check and initial functional tests
status indicator that the circuit breaker
(refer to pages 9-10).
contacts are CLOSED.
Primary tasks of this check are:
2. As soon as the circuit breaker has closed,
1. The circuit breaker must be energized the automatic spring-charging process is
with control power for this check. repeated.
2. Energize the control-power source. 3. After a satisfactory close operation is
verified, move the switchgear-mounted
3. When control power is connected to the
Close/Trip switch to the Trip position.
circuit breaker, the closing spring should
Verify by both the sound of the circuit
automatically charge. Visually verify that
breaker opening and by the main
the closing spring is charged.
contact status indicator that the circuit
Note: A temporary source of control power breaker contacts are OPEN.
and test leads may be required if the
4. After a satisfactory open operation is
control-power source has not been
verified, hold the circuit breaker manual
connected to the switchgear or circuit
Trip button and apply and maintain an
breaker. When control power is connected
electrical close signal. The circuit breaker
to the circuit breaker, the closing spring
should close, immediately trip, the close
should automatically charge.
spring should charge, and the circuit
breaker should not attempt to close
again.
Completion of these checks demonstrates
satisfactory operation of auxiliary switches,
internal relays and open and close coils.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 3: Typical vacuum interrupter contact life expectancy

Right hand limit

Rated maximum Interrupting class Vacuum
Rated short-circuit current Graph of curve (refer to
voltage kV MVA interrupter type
Figure 21)1
VS-17006 A 36
4.76 250 29 kA @ 4.76 kV; 36 kA @ 3.85 kV
VS-17040 E 36
VS-12050 B 49
4.76 350 41 kA @ 4.76 kV; 49 kA @ 4.0 kV
VS-15052 B 49
8.25 500 33 kA @ 8.25 kV; 41 kA @ 6.6 kV VS-15052 B 41
15.0 500 18 kA @ 15.0 kV; 23 kA @ 11.5 kV VS-17006 A 23
VS-15052 B 36
15.0 750 28 kA @ 15.0 kV; 36 kA @ 11.5 kV
VS-17040 E 36
15.0 1,000 37 kA @ 15.0 kV; 48 kA @ 11.5 kV VS-15052 B 48
38.0 1,500 21 kA @ 38.0 kV; 35 kA @ 23.0 kV VS-30030 D 35
Right hand limit
Rated maximum Interrupting class Vacuum
Rated short-circuit current Graph of curve (refer to
voltage kV kA interrupter type
Figure 21)1
VS-17006 A 31.5
4.76 31.5 31.5
VS-17040 E 31.5
VS-15052 B 40
4.76 40 40
VS-17040 E 40
VS-12050 B 50
4.76 50 50
VS-15052 B 50
4.76 63 63 VS-17085 F 63
VS-15052 B 40
8.25 40 40
VS-17040 E 40
15.0 20 20 VS-17006 A 20
15.0 25 25 VS-17006 A 25
VS-17006 A 31.5
15.0 31.5 31.5
VS-17040 E 31.5
VS-15052 B 40
15.0 40 40
VS-17040 E 40
15.0 50 50 VS-15052 B 50
15.0 63 63 VS-17085 F 63
15.5 20 20 VS-25008 C 20
15.5 25 25 VS-25008 C 25
15.5 31.5 31.5 VS-15052 B 31.5
15.5 40 40 VS-15052 B 40
27.6 20 20 VS-25008 C 20
27.6 25 25 VS-25008 C 25
38.0 20 20 VS-30030 D 20
38.0 25 25 VS-30030 D 25
38.0 31.5 31.5 VS-30041 D 31.5
38.0 40 40 VS-30041 D 40

Footnote:
1.
Maximum symmetrical interrupting current rating of circuit breaker (refer to Tables 11 and 12).

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 22: Typical vacuum interrupter contact life curves

Load graph "A" vacuum interrupter type VS-17006

Load graph "C" vacuum interrupter type VS-25008
Load graph "E" vacuum interrupter type VS-17040

Permissible operating cycles

100,000

50,000

20,000

10,000

5,000

2,000

1,000

500

200

100

50

20
C A E
10
1 2 5 10 20 25 31.5 40 50 100

Breaking current (symmetrical value)

Note: Right-hand vertical segment of curve is located at the maximum

symmetrical interrupting current rating of the circuit breaker, as indicated in
Table 3.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 22: Typical vacuum interrupter contact life curves (continued)

Load graph "B" vacuum interrupter type VS-12050 and VS-15052

Load graph "D" vacuum interrupter types VS-30030 and VS-30041
Load graph "F" vacuum interrupter type VS-17085

Permissible operating cycles

100,000

50,000

20,000

10,000

5,000

2,000

1,000

500

200

100

50

20
D BF
10
1 2 5 10 20 40 50 63 100

Breaking current (symmetrical value)

Note: Right-hand vertical segment of curve is located at the maximum

symmetrical interrupting current rating of the circuit breaker, as indicated in
Table 3.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Checks of the spring-charging motor

(88.0)
No additional checks of the spring-charging
motor are necessary. If it is necessary to
remove or replace the spring-charging
motor, torque motor-mounting hardware to
7.3-8 ft-lb (10-11 Nm).
Anti-pump relay
If it is necessary to remove the connections
to the anti-pump relay, use care to avoid
damaging the relay. Replace the relay if the
relay terminals are damaged or loose in the
relay body.
Vacuum interrupters
The life expectancy of vacuum interrupters
is a function of the numbers of interruptions
and magnitude of current interrupted (refer
to Table 3 and Figure 21).
The vacuum interrupters must be replaced
before the number of mechanical operations
(listed in Table 2) are reached, or when the
contacts have been eroded beyond allowed
limits. Vacuum interrupter replacement
procedures are detailed in the following
maintenance instructions.
The vacuum interrupter contact life curves
(refer to Figure 21) are offered as a guide to
expected life.

High-potential tests employ hazardous voltages.

Will cause death and serious injury.

Follow safe procedures, exclude unnecessary personnel and use safety

barriers. Keep away from the circuit breaker during application of test
voltages. Disconnect the split plug jumper from between the circuit breaker
and switchgear before conducting high-potential tests.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Vacuum interrupters may emit X-ray radiation.

Can result in serious injury.

Keep personnel more than six feet away from a circuit breaker under test.

High-potential tests High-potential test voltages

The next series of tests (vacuum-integrity The voltages for high-potential tests are
test and insulation tests) involve use of shown in Table 4.
high-voltage test equipment. The circuit
Note: This test includes not only the
breaker under test should be inside a
vacuum interrupter, but also the other
suitable test barrier equipped with warning
insulation components in parallel with the
lights.
vacuum interrupter. These include the post
Vacuum-integrity check (using dielectric insulators and the insulating coupler, as well
test) as the insulating (tension) struts between
A high-potential test is used to verify the the upper and lower vacuum interrupter
vacuum integrity of the circuit breaker. The supports. If these insulation components are
test is conducted on the circuit breaker with contaminated or defective, the test voltage
its primary contacts in the Open position. will not be sustained. If so, clean replace the
affected components, and retest.
Vacuum integrity test procedure
1. Observe safety precautions listed in the
danger and warning advisories. Table 4: High-potential test voltages
Construct the proper barrier and
warning light system. Equipment Equipment rated
Maximum ac rms Maximum dc
maximum voltage power-frequency
test voltage kV average test voltage
2. Ground the frame of the circuit breaker, rating kV withstand kV (rms)
and ground each pole not under test.
4.76 19 14 20
3. Apply test voltage (refer to Table 4)
across each pole for one minute (circuit 8.25 36 27 38
breaker Open).
4. If the pole sustains the test voltage for 15.0 36 27 38
that period, its vacuum integrity has
been verified. 15.5 50 38 53

Note: Do not use dc high-potential testers 27.6 60 45 64

incorporating half-wave rectification. These
devices produce high peak voltages. 38 80 60 85
High peak voltages will produce X-ray
radiation. DC testers producing excessive
peak voltages also show erroneous readings
of leakage current when testing vacuum
circuit breakers.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 23: Circuit breaker contact-resistance test

3H4c vacuum circuit breaker operator

As-found insulation and contact Insulation and contact-resistance test

resistance tests equipment
As-found tests verify the integrity of the In addition to the high-potential test
circuit breaker insulation system. Megger* equipment capable of test voltages as listed
or insulation resistance tests and contact- in Table 4, the following equipment is also
resistance tests conducted on equipment required:
prior to installation provide a basis of future
AC high-potential tester with test voltage
comparison to detect changes in the
of 1,500 volts, 60 Hz
protection afforded by the insulation
system. A permanent record of periodic Test equipment for contact-resistance
as-found tests enables the maintenance tests.
organization to determine when corrective
actions are required by watching for
significant deterioration in insulation
resistance, or increases in contact
resistance.
* Megger is a registered trademark of
Megger Group, Ltd.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Insulation and contact-resistance test Inspection and cleaning of circuit breaker Table 5: Maximum contact-resistance
procedure insulation
1. Observe safety precaution listed in the 1. Perform the spring-discharge check Contact
Current rating
resistance
danger and warning advisories for the (refer to page 9) on the circuit breaker A
Micro-Ohms
vacuum integrity check tests (refer to after all control power is removed. The
pages 38-39). spring-discharge check consists of: 1,200 35

2. Close the circuit breaker. Ground the a) Pressing the red Open pushbutton 2,000 30
frame of the circuit breaker, and ground
b) Pressing the black Close pushbutton 3,000 30
each pole not under test. Use manual
charging, closing and tripping c) Pressing again the red Open
procedures. pushbutton.
3. Apply the proper ac or dc (refer to Table All of these controls are on the circuit
4) high-potential test voltage between a breaker front panel (refer to Figure 1).
primary conductor of the pole and Visually verify the Discharged condition
ground for one minute. of the springs.
4. If no disruptive discharge occurs, the 2. Remove any inter-phase and outer-phase
insulation system is satisfactory. barriers if furnished (applicable for
certain types only).
5. After test, ground both ends and the
middle of each vacuum interrupter to 3. Clean barriers and post insulators using
dissipate any static charge. clean cloth dipped in isopropyl alcohol.
6. For drawout applications, connect all 4. Replace all barriers. Check all visible
points of the secondary disconnect with fasteners again for condition and
a shorting wire. For stationary tightness.
applications, disconnect secondary
Note: Do not use any cleaning compounds
circuits for the operating mechanism by
containing chlorinated hydrocarbons, such
disconnecting the multiple pin-plug at
as: trichlorethylene, perchlorethylene or
the upper right corner of the operator,
carbon tetrachloride.
and connect all pins on the operator side
with a shorting wire. Connect the These compounds will damage the
shorting wire to the high-potential lead phenylene ether copolymer material used in
of the high-voltage tester, and ground the barriers and other insulation on the
the circuit breaker housing. Starting circuit breaker.
with zero voltage, gradually increase the
Functional tests
test voltage to 1,500 volts rms, 60 Hz.
Refer to the installation checklist in the
Maintain test voltage for one minute.
installation checks and initial functional
Alternatively, the test may be conducted
tests section of this instruction manual
at 1,800 volts rms for one second.
(refer to pages 9-10). Functional tests
7. If no disruptive discharge occurs, the consist of performing at least three manual
secondary control insulation level is spring-charging checks and three automatic
satisfactory. spring-charging checks. After these tests are
complete, and the springs are fully
8. Disconnect the shorting wire, and
discharged, all fasteners and connections
reattach the multiple pin-plug (if
are checked again for tightness and
applicable).
condition.
9. Perform contact-resistance tests of the
primary contacts. The resistance should
be read between the lower and upper
connection pads (refer to Figure 22).
Contact resistance should not exceed
the values listed in Table 5.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Overhaul
Table 6: Overhaul schedule Introduction b) Remove two M4 hex-head screws and
The following procedures along with the remove solenoid.
Circuit Closing troubleshooting charts in this instruction
breaker type operations
c) Install replacement coils with new M4
manual (refer to pages 47-51), provide
x 10 hex-head screws (Siemens part #
maintenance personnel with a guide to
10,000 00-000-443-820) and new lock
SDV6 identifying and correcting possible
operations washers for M4 (Siemens part #
malfunctions of the circuit breaker.
10,000 00-000-288-316).
All others
operations Circuit breaker overhaul
d) The coil-mounting screws must be
Table 6 gives the recommended overhaul
installed using thread locking
schedule type 3AH operating mechanisms.
adhesive (Loctite #222, Siemens part
These intervals assume that the circuit
15-133-281-007) and primer (Loctite
breaker is operated under “usual service
primer T (#7471), Siemens part
conditions” as discussed in ANSI/IEEE
15-133-281-005).
C37.20.2 (for drawout circuit breakers) or
ANSI/IEEE C37.04 and elaborated in ANSI/ e) Connect wires to coils with new wire
IEEE C37.010 (for outdoor distribution terminals (Siemens part #
circuit breakers). If the circuit breaker is 15-171-600-002).
operated frequently, the overhaul interval in
3. Motor interlock
Table 6 may coincide with the maintenance
interval in Table 2. a) Remove wire connections
Replacement at overhaul b) Remove two 6-32 x 1.00 screws and
The following components are replaced dismount switch
during an overhaul of the circuit breaker,
c) Install replacement MI switch with
when required:
new 6-32 x 1.00 screws (Siemens part #
Vacuum interrupters as determined by 00-615-471-132), new lockwasher
vacuum integrity test, contact erosion or (Siemens part # 00-655-007-059)
according to overhaul schedule (refer to
d) Apply a thread locking adhesive to
Table 6)
screws using locking adhesive (see
Close coil, 52SRC above)
Trip coil, 52T e) Reconnect wires.
Trip-free drive bar mechanism (if 4. Lubricate operating mechanism
applicable) according to maintenance and lubrication
information (refer to page 32).
Motor interlock (MI) (if applicable).
5. When work is finished, operate circuit
When these parts are changed, locking
breaker and close and open several
devices must also be removed and replaced.
times, and check that all screw
These include lock washers, retaining rings,
connections are tight.
retaining clips, spring pins, cotter pins, etc.
Replacement of vacuum interrupters
1. Replace vacuum interrupter; instructions
It is recommended that vacuum interrupters
follow.
be replaced only by a qualified Siemens field
2. Close coil (52SRC) and trip coil (52T). service representative. The information in
the following sections is provided to aid in
a) Remove two “push on” terminal
understanding the replacement procedures.
connections

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Vacuum interrupters for type 3AH rated 1.1 Before starting work, the circuit
63 kA interrupting or rated 3,000 A breaker should be isolated from all
continuous current and all type 3AHc primary and control-power sources and
operators require special expertise for all stored energy discharged by
replacement and must be replaced only by a opening, closing and opening the
qualified Siemens field service circuit breaker by hand. Discharge any
representative. Accordingly, detailed static charge by grounding both ends
instructions for replacement vacuum and the middle of each vacuum
interrupters for these ratings are not interrupter. Carefully remove outer-
provided in this instruction manual. phase and inter-phase barriers.
Replacement vacuum interrupters are 1.2 Loosen the lateral bolt(s) on terminal
furnished as a complete assembly. They clamp (29.2). Employ the illustrated
have been completely tested and procedure to loosen clamp hardware
dielectrically and mechanically conditioned. (refer to Figure 25).
It is recommended that one vacuum 1.3 Withdraw pin (48.5) from insulating
interrupter be removed and replaced coupler (48.0) and levers (48.6).
completely rather than removing two or
1.4 Remove coupling pin from the eye bolt
more vacuum interrupters at a time.
(36.3).
The following procedure in check list format
1.5 Free struts (28.0) from the pole head
describes the procedure for removing and
(20.0). Loosen the strut hardware on
replacing a vacuum interrupter. Components
the pole bottom (40.0) and swing the
may be identified by reference to Figures 23
struts forward and downward.
and 24.
1.6 Loosen screws fastening the centering
Instructions herein apply for replacement of
ring (28.1).
all vacuum interrupters except type
VS-17085 vacuum interrupters, and 1.7 Remove bolt (31.2), lock washer and
interrupters on 3,000 A circuit breakers large washer at the stationary contact
having the flexible connector (refer to 29.1 of the vacuum interrupter (18 mm or
in Figure 23) electron-beam welded to the 24 mm socket with extension).
moving terminal (refer to 36.1 in Figure 23)
1.8 Using a 24 mm socket with an
of the vacuum interrupter. These
extension, loosen and remove hex-cap
interrupters must be replaced by factory-
screw fastening the pole head to the
trained personnel. Contact Siemens medium-
post insulator. Completely remove the
voltage customer service at 1-800- 333-
pole head and set aside.
7421 or 1-423-262-5700 outside the U.S.
1.9 Grasp the vacuum interrupter (30.0)
1. Removing the vacuum interrupter
and withdraw vertically. Assistance
may be required to work the terminal
Note: Special care needs to be exercised in clamp off the movable stem of the
removal or installation of hardware around vacuum interrupter. DO NOT USE
the bottom, or movable contact end, of the UNDUE FORCE OR TWISTING
vacuum interrupter. MOTION. If the terminal clamp (29.2)
cannot be easily removed, STOP!, check
The movable contact uses a metal bellows
to be certain hardware is loose, and
to maintain the vacuum seal while still
that the terminal clamp (29.2) is not
permitting up and down motion of the
binding.
contact. The bellows is rugged and reliable,
and is designed to withstand years of 2. Installing a vacuum interrupter
vertical movement. However, care should be
Note: Replacement vacuum interrupter
exercised to avoid subjecting the bellows to
(30.0) will be received from the factory with
excessive torque during removal and
an eye bolt (36.3) in place, adjusted and
replacement. Twisting the bellows through
torqued to specific requirements. DO NOT
careless bolt removal or tightening may
ALTER THE ADAPTER (EYE-BOLT)SETTING.
damage the vacuum interrupter, resulting in
loss of vacuum integrity.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 24: Vacuum interrupter replacement illustration - type 3AH

Item Description
20.0 Upper pole-support (pole head)
28.0 Strut
28.1 Centering ring
20.0
29.1 Flexible connector
31.2
29.2 Terminal clamp
29.3 Spacer (or shoulder)
30.0 Vacuum interrupter
31.2 Upper terminal bolt
36.1 Moving terminal
36.3 Eye bolt (or adapter)
40.0 Lower pole-support
48.0 Insulating coupler
48.5 Pin
28.0
48.6 Angled lever
48.9 Drive link

30.0

28.1
29.3
36.1

29.1 29.2

36.3

48.0
40.0 48.9
48.6
48.5

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Figure 25: Illustration showing required technique for fastening terminal-clamp hardware

Item Description
A Moving contact (36.1)
B Spacer (shoulder) (29.3)
C Torque wrench
D Direction of force (P)
E Terminal clamp (29.2)
F Holding wrench
G
G Vacuum interrupter

F
A
B

Position of torque wrench to avoid undue stressing of moving contact (36.1)

2.1 Inspect all silver-plated connection 2.6 Couple levers (48.6) and drive link
surfaces for cleanliness. Clean only (48.9) to the eye bolt (36.3), using the
with a cloth and solvent. Do not pin supplied. Apply retaining clips.
abrade, as this will damage the silver Appropriate pin is modestly chamfered,
plating. not to be confused with pin for the
insulating coupler.
2.2 Insert vacuum interrupter (30.0) into
the lower pole-support (40.0). Slip 2.7 Raise the terminal clamp (29.2) against
terminal clamp (29.2) into position on the step or the spacer (if applicable) of
the movable stem. the moving contact (36.1) of the
vacuum interrupter (30.0) so that the
2.3 Align vacuum interrupter and fasten
radius of the movable contact faces the
“finger tight” using heavy flat washer,
connecting surface of the flexible
lock washer and bolt (31.2).
connector (29.1). Employ technique
2.4 Fasten the pole head to the post illustrated to fasten terminal clamp
insulator (16.1) “finger tight” using (refer to Figure 25). Note opposing
hex-head bolt, lock washer and flat wrenches. Tighten the bolt(s) of the
washer. terminal clamp to a torque of 40 Nm
(30 ft-lb), taking care to see that the
2.5 Attach struts (28.0) to the upper pole-
terminal of the vacuum interrupter is
support (20.0), replace hardware
not subjected to excessive bending
(M10), but do not tighten at this time.
movement.
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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Note: Excessive bending movement exerted 3.4 Connect the insulating coupler (48.0)
while fastening the terminal clamp will using pin (48.5) and the retaining clips
damage the vacuum interrupter. provided.
2.8 Align pole head (20.0) correctly and 3.5 Repeat the measurement described in
tighten bolt fastening it to the post step 3.3 again with care to maximize
insulator. Torque M16 bolt to 130 Nm accuracy. Record your result.
(96 ft-lb). Fasten securely all bolts
3.6 Determine difference between the
associated with struts (28.0).
measurements made under steps 3.3
2.9 Tighten vacuum interrupter fastening and 3.5. Your results should be per
bolt (31.2) on the pole head (20.0) Table 7.
holding the vacuum interrupter firmly
3.7 If you fail to achieve the listed results,
by its upper insulator and operate
carefully repeat the entire procedure
levers (48.6), by hand, to see whether
making certain of your measurements.
the movable contact moves freely. If
any binding or lack of freedom is 3.8 Loosen eye bolt locking nut on
noted, loosen bolt (31.2) and adjust insulating coupler (48.0), and retain
the vacuum interrupter in pole head by position of the eye. Make adjustments
turning and moving it slightly. Torque in one-half turn increments. After
M12 bolt to 60 Nm (44 ft-lb) and M16 adjustment is completed, tighten eye
bolt to 130 Nm (96 ft-lb). bolt locking nut to 26-34 ft-lb. (35-45
Nm).
2.10 The centering ring (28.1) has been
loose and “floating” during installation 4. After eye bolt is tightened to proper
of the vacuum interrupter. Check that torque, repeat all measurement
the movable contact is free to move procedures, making certain they are in
vertically without binding, and then agreement with values indicated in
tighten the hardware which secures step 3.6.
the centering ring. Recheck that the
5. Complete all other maintenance
movable contact is free to move
procedures. Completely reassembled
vertically without binding.
circuit breaker should pass the high-
2.11 Attach insulating coupler (48.0) and potential test before it is ready for
lever (48.6) together, using pin (48.5). service.
Apply retaining clips. Correct pin has
Hydraulic shock absorber
ends that have been generously
The mechanism is equipped with a hydraulic
chamfered.
shock-absorber that functions when the
2.12 Open and close circuit breaker several circuit breaker opens (refer to item 61.8 in
times and then check to see that all Figure 6). The shock absorber should require
bolted joints and devices are tight. no adjustment. However, at maintenance
checks, the shock absorber should be
3. Checking the contact stroke
examined for evidence of leaking. If
3.1 Open the circuit breaker. evidence of fluid leakage is found, the shock
absorber must be replaced to prevent
3.2 Free insulating coupler (48.0) by
damage to the vacuum interrupter bellows.
removing pin (48.5). The vacuum
interrupter contacts must now close
automatically as a consequence of
atmospheric pressure.
3.3 Observe the terminal clamp (29.2)
through the openings on each side of
the pole bottom (40.0). Using vernier
calipers, measure the distance from the
bottom surface of the terminal clamp
to the bottom edge of the cutout
opening. Measure carefully and record
your result.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Technical data and

troubleshooting
Rated maximum Interrupting Rated short- Vacuum Table 7: Vacuum interrupter stroke
Continuous current Stroke2
voltage class circuit current interrupter
kV MVA kA Type A mm
Footnotes:
29 kA@4.76 kV; 1.
The vacuum interrupter type des-
VS-17006 1,200, 2,000 7-9 (3AH)
36 kA@3.85 kV ignation is labeled on the vac-
4.76 250
29 kA@4.76 kV; uum interrupter. If the vacuum
VS-17040 1,200, 2,000 7-9 interrupter installed does not
36 kA@3.85 kV
match that indicated in this
41 kA@4.76 kV; VS-12050 1,200, 2,000 7-9
4.76 350 table, contact the nearest Sie-
49 kA@4.0 kV VS-15052 1,200, 2,000, 3,000 7-9
mens representative.
33 kA@8.25 kV; 2.
If you need assistance achieving the
8.25 500 VS-15052 1,200, 2,000, 3,000 7-9
41 kA@6.6 kV indicated stroke setting, con- tact
18 kA@15.0 kV; the nearest Siemens
15.0 500 VS-17006 1,200, 2,000 7-9 representative.
23 kA@11.5 kV
28 kA@15.0 kV; VS-15052 1,200, 2,000, 3,000
15.0 750 7-9
36 kA@11.5 kV VS-17040 1,200, 2,000
37 kA@15.0 kV;
15.0 1,000 VS-15052 1,200, 2,000, 3,000 7-9
48 kA@11.5 kV
21 kA@38.0 kV;
38.0 1,500 VS-30030 1,200, 2,000, 3,000 18-22
35 kA@23.0 kV
Rated maximum Interrupting Rated short- Vacuum
Continuous current Stroke2
voltage class circuit current interrupter
kV kA kA Type A mm
VS-17006 1,200, 2,000 7-9 (3AH)
4.76 31.5 31.5 kA@4.76 kV
VS-17040 1,200, 2,000 7-9
VS-15052 1,200, 2,000, 3,000
4.76 40 40 kA@4.76 kV 7-9
VS-17040 1,200, 2,000
VS-12050 1,200, 2,000 7-9
4.76 50 50 kA@4.76 kV
VS-15052 1,200,2,000, 3,000 7-9
VS-15052 1,200, 2,000, 3,000
8.25 40 40 kA@8.25 kV 7-9
VS-17040 1,200, 2,000
15.0 20 20 kA@15.0 kV VS-17006 1,200, 2,000 7-9
15.0 25 25 kA@15.0 kV VS-17006 1,200, 2,000 7-9
VS-17006 1,200, 2,000 7-9
15.0 31.5 31.5 kA@15.0 kV
VS-17040 1,200, 2,000 7-9
VS-15052 1,200, 2,000, 3,000
15.0 40 40 kA@15.0 kV 7-9
VS-17040 1,200, 2,000
15.0 50 50 kA@15.0 kV VS-15052 1,200, 2,000, 3,000 7-9
15.0 63 63 kA@15.0 kV VS-17085 1,200, 2,000, 3,000 10-11
15.5 20 20 kA@15.5 kV VS-25008 1,200, 2,000 15-16
15.5 25 25 kA@15.5 kV VS-25008 1,200, 2,000 15-16
15.5 31.5 31.5 kA@15.5 kV VS-15052 1,200, 2,000, 3,000 7-9
15.5 40 40 kA@15.5 kV VS-15052 1,200, 2,000, 3,000 7-9
27.6 20 20 kA@27.6 kV VS-25008 1,200, 2,000 15-16
27.6 25 25 kA@27.6 kV VS-25008 1,200, 2,000 15-16
38.0 20 20 kA@38.0 kV VS-30030 1,200, 2,000, 3,000 18-22
38.0 25 25 kA@38.0 kV VS-30030 1,200, 2,000, 3,000 18-22
38.0 31.5 31.5 kA@38.0 kV VS-30041 1,200, 2,000, 3,000 18-22
38.0 40 40 kA@38.0 kV VS-30041 1,200, 2,000, 3,000 18-22

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 8: Troubleshooting

Problem Symptoms Possible causes and remedies

1. Secondary control circuit is de-energized or control
circuit fuses are blown. Check and energize or replace
if necessary.

2. Secondary multi-pin plug contacts A1 or D16 are not

engaging. Check and replace if required.

3. Damage to wiring, terminals or connectors. Check

Closing spring will not automatically charge. and repair as necessary.

4. Failure of charging motor (88.0). Replace if required.

5. Motor cut-off switch LS21 or LS22 fails to operate.

Replace if necessary.

6. Mechanical failure of operating mechanism. Check

and contact the factory or Siemens field service at
1-800-333-7421 or 1-423-262-5700 outside the U.S.
1. Secondary control circuit de-energized or control
circuit fuses blown. Correct as indicated.

Circuit breaker fails to close. 2. No closing signal to secondary disconnect pin A2.
Check for continuity and correct protective relay
logic.

Closing coil or solenoid 3. Secondary disconnect contacts 13 or 15 are not

(52SRC) fails to energize. engaging. Check and correct as required.
No sound of circuit 4. Failure of anti-pump relay (52Y) contacts 21 to 22, 31
breaker closing. to 32 or 13 to 14. Check and replace as required.
Closing springs charge
but circuit breaker does 5. Failure of close coil (solenoid) (52SRC). Check and
not close. replace as required.

6. Auxiliary switch NC contacts 41 to 42 are open when

circuit breaker contacts are open. Check linkage and
switch. Replace or adjust as necessary.

Closing coil energizes.

Sound of circuit breaker 1. Mechanical failure of operating mechanism. Check
closing is heard, but and contact the factory or Siemens field service at
circuit breaker contacts 1-800-333-7421 or 1-423-262-5700 outside the U.S.
do not close.

1. Nuisance or false closing signal to secondary

disconnect multi-pin plug contact. Check protective
relay logic. Correct as required.
Electrical problem
2. Closing coil (52SRC) terminal A2 is shorted-to-
Nuisance or false close ground. Check to determine if problems are in wiring
or coil. Correct as required.
1. Mechanical failure of operating mechanism. Check
Mechanical problem and contact the factory or Siemens field service at
1-800-333-7421 or 1-423-262-5700 outside the U.S.

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 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 8: Troubleshooting (continued)

Problem Symptoms Possible causes and remedies

1. Secondary control power is de-energized or
control power fuses are blown. Correct as
indicated.

2. Damage to wiring, terminals or connectors.

Check and repair as necessary.

3. No tripping signal to secondary disconnect

contact C2. Check for continuity and correct
protective relay logic.
Tripping coil or solenoid (52T) does not
energize. There is no tripping sound. 4. Secondary multi-pin plug contacts C1 or D2
are not engaging. Check and replace if
required.

5. Failure of trip coil (52T). Check and replace

Circuit breaker will not trip. if necessary.

6. Auxiliary switch 52a NO contacts 23 to 24

or 33 to 34 are open when circuit breaker is
closed. Check linkage and switch. Replace
or adjust as necessary.
Tripping coil (52T) energizes. No tripping
1. Failure of tripping spring or its mechanical
sound is heard, and circuit breaker contacts do
linkage. Check and replace if required.
not open. In other words, they remain closed.
1. Mechanical failure of operating mechanism.
Check and contact the factory or Siemens
Tripping coil (52T) energizes. Tripping sound is field service at 1-800-333-7421 or 1-423-
heard, but circuit breaker contacts do not 262-5700 outside the U.S.
open.
2. One or more of the vacuum interrupters are
held closed. Check and replace as necessary.
1. Tripping signal remains energized on
Electrical problem secondary multi-pin plug contact C2.

2. Check for improper protective relay logic.

Nuisance or false trip
1. Mechanical failure of operating mechanism.
Check and contact the factory or Siemens
Mechanical problem
field service at 1-800-333-7421 or 1-423-
262-5700 outside the U.S.

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3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 9: Circuit breaker control data

ANSI/IEEE C37.09 control voltages Spring charging motor

Close
Trip coil
coil Run Inrush
Range Charging
(Average)1 (Peak)
Nominal
Close Trip A1 A1 A A Seconds

24 Vdc 19-28 14-28 5.7 15/---- ---- ---- ----

48 Vdc 36-56 28-56 11.4 11.4/303 8 25 10

125 Vdc 100-140 70-140 2.1 4.8/7.43 4 18 10

250 Vdc 200-280 140-280 2.1 4.2/9.63 2 10 10

120 Vac 104-127 104-127 2.0 ----2 6 ---- 10

240 Vac 208-254 208-254 2.0 ----2 3 ---- 10

Footnotes:
1.
Current at nominal voltage
2.
Capacitor trip
3.
Value preceding slash (/) is the current for the standard trip coil with standard rating interrupting time. Value
following (/) is current for optional trip coil with three-cycle interrupting time.
4. --------------
means this selection is not available at this voltage.

Table 10: Interrupting capacity auxiliary switch contacts2

Continuous Control circuit voltage

Type of
current
circuit
amperes 120 Vac 240 Vac 48 Vdc 125 Vdc 250 Vdc

Non-
10 10 5 10/301 9.6 4.8
inductive

Inductive 10 6 3 10 6 3

Footnotes:
1.
Two contacts in series.
2.
All switches are non-convertible.

50
 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 11: Type 3AH vacuum circuit breaker ratings ("constant kA" ratings basis)

Maximum
Withstand voltage Continuous Short-circuit
These ratings are in
design accordance with:
Voltage levels current7 (I)3,4
voltage (V)1
Circuit breaker range ANSI/IEEE C37.04
type factor Lightning
Power Standard for Ratings and
(K)2 impulse
kV rms frequency A rms kA rms sym Requirements for AC High-
(BIL)
kV rms
kV crest Voltage Circuit Breakers
with Rated Maximum
5-3AH-31.5 4.76 1.0 19 60 1,200, 2,000 31.5
Voltages above 1000 V
1,200, 2,000, ANSI/IEEE C37.09
5-3AH-40 4.76 1.0 19 60 40
3,000 Standard Test Procedure
5-3AH-50 4.76 1.0 19 60
1,200, 2,000,
50
for AC High-Voltage Circuit
3,000 Breakers with Rated
1,200, 2,000, Maximum Voltage above
5-3AH-63 4.76 1.0 19 60 63
3,000 1000 V
1,200, 2,000,
7-3AH-40 8.25 1.0 36 95 40 ANSI/IEEE C37.010
3,000
Guide for AC High-Voltage
15-3AH-20 15.0 1.0 36 95 1,200, 2,000 20 Circuit Breakers > 1000 Vac
Rated on a Symmetrical
15-3AH-25 15.0 1.0 36 95 1,200, 2,000 25 Current Basis.

1,200, 2,000, Footnotes:

15-3AH-31.5 15.0 1.0 36 95 31.5 1.
Maximum design voltage for which
3,000
the circuit breaker is designed
1,200, 2,000, and the upper limit for operation.
15-3AH-40 15.0 1.0 36 95 40
3,000 2.
K is listed for information
1,200, 2,000, purposes only. For circuit
15-3AH-50 15.0 1.0 36 95 50
3,000 breakers rated on a "constant kA"
ratings basis, the voltage range
1,200, 2,000,
15-3AH-63 15.0 1.0 36 95 63 factor is 1.0.
3,000 3.
All values apply to polyphase and
15.5-3AH-20 15.5 1.0 50 110 1,200, 2,000 20 line-to-line faults.
4.
Standard duty cycle is O - 0.3 s -
CO - 3 min. - CO.
15.5-3AH-25 15.5 1.0 50 110 1,200, 2,000 25 5.
Standard rating interrupting time
is five-cycles (83 ms). Optional
15.5-3AH-31.5 15.5 1.0 50 110 1,200, 2,000 31.5 rated interrupting time of three-
cycles (50 ms) is available
1,200, 2,000, (except with 24 Vdc tripping).
15.5-3AH-40 15.5 1.0 50 110 40 6.
150 kV BIL is for drawout
3,000
applications. 200 kV BIL is for
27-3AH-20 27.6 1.0 60 150 1,200, 2,000 20 type SDV6 with appropriate
construction.
7.
Continuous current capability
27-3AH-25 27.6 1.0 60 150 1,200, 2,000 25
may be increased by the use of
forced-cooling (fan-cooling) in
38-3AH-20 38.0 1.0 80 150/2006 1,200, 2,000 20 the switchgear together with
increased bus bar capacity.
38-3AH-25 38.0 1.0 80 150/2006 1,200, 2,000 25

1,200, 2,000,
38-3AH-31.5 38.0 1.0 80 150/2006 31.5
3,000
1,200, 2,000,
38-3AH-40 38.0 1.0 80 150/2006 40
3,000

51
3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 11: Type 3AH vacuum circuit breaker ratings (new "constant kA" ratings basis) (continued)

Permissible
Interrupting Max. sym. % dc Short-time
tripping delay Closing and latching (momentary)
time5 interrupting (I) component current (I) (3 s)
Circuit breaker (y)
type Asymmetrical Peak
ms/cycles s kA rms sym % kA rms (1.55 x I) (2.6 x I)
kA rms kA peak

5-3AH-31.5 83/5 2 31.5 47 31.5 49 82

5-3AH-40 83/5 2 40 47 40 62 104

5-3AH-50 83/5 2 50 47 50 78 130

5-3AH-63 83/5 2 63 47 63 98 164

7-3AH-40 83/5 2 40 47 40 62 104

15-3AH-20 83/5 2 20 47 20 31 52

15-3AH-25 83/5 2 25 47 25 39 65

15-3AH-31.5 83/5 2 31.5 47 31.5 49 82

15-3AH-40 83/5 2 40 47 40 62 104

15-3AH-50 83/5 2 50 47 50 78 130

15-3AH-63 83/5 2 63 47 63 98 164

15.5-3AH-20 83/5 2 20 47 20 31 52

15.5-3AH-25 83/5 2 25 47 25 39 65

15.5-3AH-31.5 83/5 2 31.5 47 31.5 49 82

15.5-3AH-40 83/5 2 40 47 40 62 104

27-3AH-20 83/5 2 20 47 20 31 52

27-3AH-25 83/5 2 25 47 25 39 65

38-3AH-20 83/5 2 20 47 20 31 52

38-3AH-25 83/5 2 25 47 25 39 65

38-3AH-31.5 83/5 2 31.5 47 31.5 49 82

38-3AH-40 83/5 2 40 47 40 62 104

52
 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 12:Type 3AH vacuum circuit breaker ratings (historic "constant MVA" ratings basis)

Nominal
These ratings are in
Maximum Voltage accordance with:
Nominal three-
design Continuous range Withstand voltage
voltage phase
voltage current11 factor levels ANSI/IEEE C37.04-1979
class MVA
Circuit class7
(V)1 (K)2 Standard Rating Structure
breaker type for AC High-Voltage Circuit
Lightning Breakers Rated on a
Power
kV MVA kV rms A rms ---- frequency
impulse Symmetrical Current Basis
(BIL)
kV rms ANSI C37.06-1987
kV crest
AC High-Voltage Circuit
5-3AH-250,
4.16 250 4.76 1,200, 2,000 1.24 19 60 Breakers Rated on a
5-3AHc-250 Symmetrical Current Basis -
Preferred Ratings and
5-3AH-350, 1,200, Related Required
4.16 350 4.76 1.19 19 60
5-3AHc-350 2,000, 3,000 Capabilities
ANSI/IEEE C37.09-1979
1,200, Standard Test Procedure for
7-3AH-500 7.2 500 8.25 1.25 36 95
2,000, 3,000
AC High-Voltage Circuit
Breakers Rated on a
1,200, Symmetrical Current Basis
15-3AH-500 13.8 500 15.0 1.30 36 95
2,000, 3,000
ANSI/IEEE C37.010-1979
Application Guide for AC
1,200,
15-3AH-750 13.8 750 15.0
2,000, 3,000
1.30 36 95 High-Voltage Circuit
Breakers Rated on a
Symmetrical Current Basis.
1,200,
15-3AH-1000 13.8 1000 15.0 1.30 36 95
2,000, 3,000

38-3AH-1500 38.0 1,500 38.0 1,200, 2,000 1.65 80 150

Footnotes: 4.
Within the limitations stated in 10.
High close and latch
1.
Maximum design voltage for which the circuit ANSI/IEEE C37.04-1979, all values apply to (momentary) rating available for
breaker is designed and the upper limit for polyphase and line-to-line faults. For single special application.
operation. phase-to-ground faults, the specific conditions 11.
Continuous current may be
2.
K is the ratio of the rated maximum design stated in clause 5.10.2.3 of increased by the use of forced-
voltage to the lower limit of the range of ANSI/IEEE C37.04-1979 apply. cooling (fan-cooling) in the
operating voltage in which the required 5.
Current values in this row are not to be exceeded switchgear, together with
symmetrical and asymmetrical interrupting even for operating voltage below 1/K times rated increased bus bar capacity.
capabilities vary in inverse proportion to the maximum design voltage. For operating voltages
operating voltage. between rated maximum design voltage and 1/K
3.
To obtain the required symmetrical interrupting times rated maximum design voltage, follow
capability of a circuit breaker at an operating Footnote 5.
voltage between 1/K times rated maximum 6.
Current values in this row are independent of
design voltage and rated maximum design operating voltage up to and including rated
voltage, the following formula shall be used: maximum voltage.
Required symmetrical interrupting capability = 7.
"Nominal three-phase MVA class" is included for
rated short-circuit current (I) x [(rated maximum reference only. This information is not listed in
design voltage)/(operating voltage)]. For ANSI C37.06-1987.
operating voltages below 1/K times maximum 8.
Standard duty cycle is O - 15 s - CO.
design voltage, the required symmetrical 9.
Standard rating interrupting time is five-cycles
interrupting capability of the circuit breaker shall (83 ms). Optional rated interrupting time of
be equal to K times rated short-circuit current. three-cycles (50 ms) is available (except with
24 Vdc tripping).

53
3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 12:Type 3AH vacuum circuit breaker ratings (historic "constant MVA" ratings basis) (continued)

Short-circuit Rated
(at rated maximum Maximum Short-time
Permissible
maximum Interrupting design symmetrical current (I) Closing and latching
tripping delay
design time9 voltage (V) interrupting (three (momentary)
(y)
Circuit breaker voltage) divided by K (K x I)5 seconds)
type (I)3, 4, 8 (= V/K)
Asymmetrical Peak
(1.6 x (2.7 x
kA rms sym ms / cycles Sec kA rms kA rms sym kA rms
K x I)6 K x I)6
kA rms kA peak

5-3AH-250,
29 83 / 5 2 3.85 36 36 58/7810 97/13210
5-3AHc-250

5-3AH-350,
41 83 / 5 2 4.0 49 49 78 132
5-3AHc-350

7-3AH-500 33 83 / 5 2 6.6 41 41 66/7710 111/13010

15-3AH-500 18 83 / 5 2 11.5 23 23 37/5810 62/9710

15-3AH-750 28 83 / 5 2 11.5 36 36 58/7710 97/13010

15-3AH-1000 37 83 / 5 2 11.5 48 48 77 130

38-3AH-1500 21 83/5 2 23.0 35 35 56 95

54
 3AH3 & 3AHc Vacuum Circuit Breaker Operator Modules | Instruction Manual

Table 13: Type 3AH3 vacuum circuit breaker weight in lbs (kg) (circuit breaker operator only)2

Circuit breaker type Weight in lbs (kg)1 Footnote:

1.
Add 100 lbs (45 kg) for
Interrupting Continuous current packaging.
Maximum voltage capability kA
2.
For weights of circuit breakers
kV (MVA) with the type 3AHc operator,
1,200 A 2,000 A 3,000 A refer to the instruction manual
symmetrical)
for the circuit breaker.
4.76 31.5 (250) 242 (110) 264 (120) ----
4.76 40 246 (112) 268 (122) 390 (177)
4.76 50 (350) 330 (150) 363 (165) 396 (180)
4.76 63 432 (196) 441 (200) 463 (210)
8.25 40 (500) 246 (112) 268 (122) 390 (177)
15.0 20 (500) 165 (75) 257 (117) ----
15.0 25 165 (75) 257 (117) ----
15.0 31.5 (750) 242 (110) 264 (120) ----
15.0 40 246 (112) 268 (122) 390 (177)
15.0 50 (1,000) 330 (150) 363 (165) 396 (180)
15.0 63 436 (198) 445 (202) 467 (212)
15.5 20 262 (119) 278 (126) ----
15.5 25 273 (124) 298 (131) ----
15.5 31.5 298 (135) 313 (142) 385 (175)
15.5 40 309 (140) 324 (147) 390 (177)
27.6 20 276 (125) 291 (132) ----
27.6 25 287 (130) 302 (137) ----
38.0 20 353 (160) 375 (170) 386 (175)
38.0 25 353 (160) 375 (170) 386 (175)
38.0 31.5 363 (165) 385 (175) ----
38.0 40 375 (170) 397 (180) 408 (185)

Table 14: Circuit breaker operating times (type 3AH3 operator)

Spring charging time ≤ 10 s

Up to 15.5 kV ≤ 55 ms
Close time from energizing close coil at rated
Over 15.5 kV up to 27.6 kV ≤ 65 ms
control voltage to contact touch (last pole)
Over 27.6 kV up to 38 kV ≤ 70 ms

Up to 15.5 kV ≤ 56 ms
5-cycle interrupting time
Over 15.5 kV up to 27.6 kV ≤ 56 ms
(83 ms)
Over 27.6 kV up to 38 kV ≤ 56 ms
Opening time from
Up to 15.5 kV ≤ 43 ms
energization trip coil at
3.5-cycle interrupting time
rated control voltage to Over 15.5 kV up to 27.6 kV ≤ 43 ms
(58 ms)
contact part (last pole),
Over 27.6 kV up to 38 kV ≤ 43 ms
not including arcing time
Up to 15.5 kV ≤ 38 ms
3-cycle interrupting time
Over 15.5 kV up to 27.6 kV ≤ 38 ms
(50 ms)
Over 27.6 kV up to 38 kV ≤ 38 ms

55
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Order No.: E50001-F710-A251-V4-4A00
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© 2020 Siemens Industry, Inc.

The technical data presented in this document is based on an actual case

or on as-designed parameters, and therefore should not be relied upon for
any specific application and does not constitute a performance guarantee
for any projects. Actual results are dependent on variable conditions.
Accordingly, Siemens does not make representations, warranties, or
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