ABB Power T&D Company Inc.

Descriptive Bulleti n
Relay Division 41-165E

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Coral Springs, FL
Allentown, PA Page 1

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Type COV
September, 1990 Device Number: 51/27
Supersedes DB 41-115, pages 1-8,

Voltage Controlled
dated February, 1988
Mailed to: E, 0, C/41-100A

Overcurrent Relay

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Descriptive Bulletin
41-165E

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Page 2

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App lica t ion in the air gap formed by the electromagnet Stationary Contact: Made of pure silver.
The COV relay provides back-up protection and the magnetic core. The electromagnet Will close 30 amperes at 250 volts dc. Has
for the generator and system from damage has two pairs of voltage coils. Each pair of sufficient wipe to assure positive contact. On
due to phase faults which are not cleared diametrically opposed coils is connected in double trip relays, adjustment of '!s.-inch
by primary relays and associated breakers. series. In addition, one pair is in series with contact follow or "wipe" is obtained by use
an adjustable resistor which provides the of a vernier adjusting screw on the stationary
It consists of a low-burden time-overcurrent necessary voltage drop-out adjustment, as contact plate.

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unit which is torque controlled by a high­ well as to shift the phase angle of one flux
speed cylinder-design voltage unit, and is with respect to the other in order to produce Moving Contact: Clamped to the insulated
applicable where it is desired to set the rotational torque of the cylinder. section of the induction disc shaft. Electrical

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overcurrent unit to operate on less than full connection is made through the spiral spring,
load current when the voltage decreases A spiral spring adjuster is located on the from the moving contact to the spring ad­
below a predetermined value. underside of the supporting bridge and is juster frame, then to the relay terminal. Con­
used to adjust the minimum setting of 80 volts. tacts will close 30 amperes at 250 volts dc.
Less than full load setting of the over-
current unit is required in vvercurrent pro­ Supporting Bridge: Houses the upper Damp in g Magnet: Made of high strength

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tection of generators because the syn­ guide bearing of the moving element. Alnico. Controls operating time of the relay
chronous reactance of the machine limits
at low current values.
the fault current during sustained faults to Stationary Contact: Made of silver. Spring
about the same or less than rated load current. mounted within circular assembly to pro­
Induction Disc: Spiral shaped to compen­
vide adequate contact follow.
sate for spring wind-up throughout moving
Since the voltage and overcurrent units of
contact travel; provides accurate pickup at

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the COV relay are independently adjustable, Moving Contact: Also made of silver, and
any disc position.
the voltage controlled COV is preferable to attached to the molded hub of the moving
a voltage restrained type because of sim­ cylinder unit. The contact can be adjusted to
plified application and setting. The timing close over a range of 80 to 100 volts. It Spring Adjuster: Used to set the minimum
of a voltage restrained relay is affected by opens if the voltage is higher than the set trip current of the relay, and to provide in­
bus voltage variation, making it difficult to value. Drop-out ratio is 98% of pickup, or between tap pickup adjustment when desired.
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coordinate with primary relays. higher.
(3) Indicating Contactor Switch (ICS)
Generator three-phase faults cannot be Adjustable Resistor: Provides adjustment of The dc Indicating Contactor Switch unit is a
detected by negative sequence current the voltage unit between 80 and 100 volts ac small clapper type device having a magnetic
relays. Hence, one type COV relay is recom­ (mounted on rear of relay chassis). armature to which leaf-spring mounted
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mended for generator back-up protection, in contacts are attached. The armature is at­
conjunction with one type sao negative (2) Overcurrent Unit tracted to the core when the coil is energized
sequence current relay. If the sao is not Consists of an "E" shaped laminated core at or above pick-up value, causing the moving
used, three COV relays are required. which has a main tapped coil, and a shading contacts to bridge two stationary contacts,
coil on one of the outer legs to shift the flux completing the trip circuit. The ICS contacts
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out of phase.

Relay Type Time Curve This out-of-phase flux interacts with the
main coil flux to create a torque on the in­
COV-6 Definite Minimum duction disc. Disc rotation is opposed by the
COV-7 Moderately Inverse
spiral spring which resets the contacts to
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COV-8 Inverse
COV-9 Very Inverse their normal position when applied current
COV-11 Extremely Inverse is below tap value setting.

Frame: One-piece die-cast aluminum.

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Overcurrent Unit Tap Range (Amperes) Assures accurate and permanent alignment are connected in parallel with the main relay
0.5-2.5 2-6 4-12 of all components. contacts, and relieve them of carrying heavy
trip currents. The main relay contacts will
The relays may have either single or double Tap Blo ck : Indicates minimum current re­ close 30 amperes at 250 volts dc, and the ICS
circuit closing contacts for tripping either one quired to close relay contacts. contacts will safely carry this current long
or two circuit breakers. enough to trip a circuit breaker.
Tap Screw: Two supplied. When changing
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taps, the spare is inserted into the new tap The target is reset external to the case by a
Vo l t a ge Unit Volts (Line-to-Line)
position prior to removing the already inserted push rod located at the bottom of the relay
one from the old position. This prevents case cover.
The contact is adjustable over a range of 80
open-circuiting of the associated current
to 100 volts. The contact will open if the
transformers. (4) ICS Taps
voltage is higher than the set value. The
Taps on the front of the relay provide con­
dropout ratio of the unit is 98% or higher.
Magnetic Plugs: May be threaded into or nection of the Indicating Contactor Switch
out of the magnetic circuit to control satura­ for either 0.2 (left) or 2.0 (right) ampere dc
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C o nstr uct io n tion and adjust calibration at high currents. minimum pick-up setting.

(1) Vol ta ge Unit Time Dial: Indicates initial position of the When the protective relay energizes a WL
Induction cylinder type. The moving element moving contact over a 2600 range. It is relay rated 125 or 250 volts dc, the 0.2
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consists of a spiral spring, a contact carrying indexed from position V. (minimum time) to ampere is recommended. The 2.0 ampere
arm, and an aluminum cylinder which rotates position 11 (maximum time). tap is used on 24 or 48 volt dc circuits ener­
gizing a WL relay.

September, 1990
 Descriptive Bulletin
41-165E

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Page 3

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September, 1990
Descriptive Bulletin
41-165E

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Page 4

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Time-Overcurrent Unit Coordination Typical Tripping Characteri sticsCD
Type COV back-up relays should use the
100 I
same operating time characteristics as the
------------,---------------------------
primary protective relays on the adjacent I
system should be used to assure selective cu
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coordination.
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A minimum coordinating time of 0.3 sec­ '0
ond, plus breaker operating time, is recom­ Cfl.
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mended between the COV relay and the
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relays with which coordination is to be

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effected. .s
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Overcurrent unit settings are defined either
by (a) time elial setting and current tap set­
0 '--___;;;:;
ting or (b) tap setting and multiples of tap
o 50 100 150 200 250
vallie (;urrent applle(i- providing a specific

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Current in % of Full Load (5 Amps)
()pm(itli1�l time.
CD 90 volt setting when shipped from factory.

Instantaneous Trip
fhe COV Illay be equipped with the liT unit. The liT provides high speed protection from Suggested Settings
!t provides hlS:jhspeed clearing of severe heavy fault currents. Also mounted on the (Normal Application)
faults It IS a pp li cabl e onl y if the fault contri­ test-jack pedestal, the Indicating Instantaneous

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tJutlon from the system to a fault at the ter­ Trip is similar in construction to the Indicating 1. Voltage Unit
·ninals of the m ac h ine !veatly exceeds the Contactor Switch, with the exception that Set for 90 volts drop-out (80 to 100 volts
(lachine slJhtransient contribution and ct's it is ac operated and is adjustable over a adjustable range).
,ne useel 011 lht� system Side rather than the range of 1 to 4 times minimum pickup. Vari­
neutral side of the mdchine. able pickup is provided by core-screw ad­ 2. Overcurrent Range
justment on top of switch. When energized Set on 2.0 ampere tap (2-6 ampere range).
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Indicating Instantaneous Trip (liT) above pickup setting, liT contacts close to
complete the trip circuit and the target drops. 3. Time Dial
The liT unit is accurate within 10% of setting Set for selective time coordination with
and has a variable drop-out to pickup ratio relays on adjacent circuits
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from 65% at minimum setting to 90% at

maximum setting. 4. Instantaneous
Set above maximum contribution to an
external fault.
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Characteristics Further Information

List Prices: PL 41-020
Voltage Unit Burden Data and Thermal Technical Data: TD 41-025
Capacities Instructions: IL 41-116
Drop-out Ratio Burden at Voltage Rating,
Renewal Parts: RPD 41-919
Frequency Drop out
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:yclcs AdJllstment: in Percent of 120 Volts in Continuous Flexitest Case Dimensions: DB 41-076
Volts Pickup Volt-AmperesCD Contactor Switches: DB 41-081
Other Protective Relays:
SO 80-100 98 7.2 132
�) O 80� 100 98 8.0 132 Application Selector Guide, TD 41-016

, Averag" for Vilrl()US SHttlrlUS

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September, 1990
 ABB Power T&D Company Inc.
II
Descriptive Bulletin
Relay Division

om
41-165E
Coral Springs, FL
1- Allentown, PA Page 5

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Type COV
December, 1990
Supersedes TO 41-020, Type COV on

Voltage Controlled
pages 13 and 14, dated November, 1987
Mailed to: E, 0, C/41-100A

Overcurrent Relay

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Overcurrent, Voltage Controlled, Non-Directional, Single-Phase, (Device Number: 27/51)
Type Time Adjustable Contacts Indicating Current Range: Amps Ac Relay Data
Curve
--------
Voltage Contactor
Time Instantaneous Internal Style Case
Range Switch@
Unit Trip: liT Unit@) Schematic Number Size
COV-6<D Definite 80-100 Spst-cc 0.2/2.0 0.5-2.5 None 183A047 288B774A19 FT-21
volts ac amp dc 2-6 1878 495
4-12

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1878 496
0.5-2.5 2-8 183A048 288B774A20
4-16 288B774A21
10-40 288B774A22
2-6 2-8 183A048 1878 497
4-16 1878 498
10-40 1878 499

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20-80 1878 500
4-12 4-16 183A048 1878 501
10-40 1878 502
20-80 1878 503
40-160 1878 504
COV-7<D Moderately 80-100 Spst-cc 0.2/2.0 0.5-2.5 None 183A047 288B773A19 FT-21
Inverse volts ac amp dc 2-6 1878 505
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4-12 1878 506
0.5-2.5 2-8 183A048 288B773A20
4-16 288B773A21
10-40 288B773A22--_.---- - -

2-6 2-8 183A048 1878 507

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4-16 1878 508

10-40 1878 509
20-80 1878 510
4-12 4-16 183A048 1878 511
10-40 1878 512
20-80 1878 513
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40-160 1878 514

COV-8<D Inverse 80-100 Spst-cc 0.2/2.0 0.5-2.5 None 183A047 288B776A20 FT-21
volts ac amp dc 2-6 1878 243®
4-12 1878 244
0.5-2.5 2-8 183A048 288B776A21
4-16 288B776A22
10-40 288B776A23
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2-6 2-8 183A048 1878 515

4-16 1878 516
10-40 1878 517
20-80 1878 518
4-12 4-16 183A048 1878 519
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10-40 1878 520

20-80 1878 521
40-160 1878 522

® Denotes item available from stock. Rating of ICS unit used in specific types of relays is shown @) ITT: Indicating Instantaneous Trip rated per ranges shown
<D 50 Hertz relays and auxiliaries can be supplied at same in price tables. All other ratings must be negotiated. in price tables. Unit is nondirectionai, adjustable. and has
price. Order "Similar to Style Number .......... , except target actuated when coil is energized at or above pickup
50 Hertz". When ac current is necessary in a control trip circuit. the setting. Unit has a dropout ratio of 65% at minimum setting
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@ ICS: Indicating Contactor Switch (dc current operated) hav­ ICS unit can be replaced by an ACS unit. and 90% at maximum setting.
ing seal·in contacts and indicating target which are actuated
when the ICS coil is energized 'at or above pickup current The ACS unit may be supplied in place of an ICS unit at no
setting. Suitable for dc control voltages up to and including additional cost. Specify system voltage rating on order.
250 volts dc. Two current ranges available:
(1) 0.212.0 amps dc, with tapped coil.
(2) 1.0 amp dc, without taps.
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Descriptive Bulletin

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41-165E

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Overcurrent, Voltage Controlled, Non-Directional, Single-Phase, (Device Number: 27/51), Continued
Type Time Ad'ustable
l Contacts Indicating Current Range: Amps Ac Relay Data
Curve Contactor --"'-:- ----'. --- ----!-'-'- -- � ------ -= -
Vo tage =
T:-im
- e
-- n - n-
I sta ta -n-eu
- o- s .,--- -
Internal Style -Cas- e
Range Switch@
Unit Trip: liT Unit® Schematic Number Size
COV-9<D Very 80-100 Spst-cc 0.212.0 0.5-2.5 None 183A047 288B775A19 FT-21
Inverse volts ac amp dc 2-6 1876 245

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4-12 1876 246
0.5-2.5 2-8 183A048 288B775A20
4-16 288B775A21
10-40 288B775A22

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2-6 2-8 183A048 1878 523
4-16 1878 524
10-40 1878 525
20-80 1878 526
4-12 4-16 183A048 1878 527
10-40 1878 528
20-80 1878 529
40-160 1878 530

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COV·11<D Extremely 80-100 Spst-cc 0.212.0 0.5-2.5 None 183A047 1956 083 FT·21
Inverse volts ac amp dc 2-6 1956 084
4-12 1956 085
0.5-2.5 2-8 183A048 1956 086
4-16 1956 087
10-40 1956 088

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2-6 2-8 183A048 1956 089
4-16 1956 090
10-40 1956 091
20-80 1956 092
4-12 4-16 183A048 1956 093
10-40 1956 094
20-80 1956 095
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40-160 1956 096

<D50 Hertz relays and auxiliaries can be supplied at same Rating of ICS unit used in specific types of relays is shown ® ITT: Indicating Instantaneous Trip rated per ranges shown
price. Order "Similar to Style Number ......... " except in price tables. All other ratings must be negotiated. in price tables. Unit is nondirectional. adjustable. and has
50 Hertz". target actuated when coil is energized at or above pickup
@ ICS: Indicating Contactor Switch (dc current operated) hav- When ac current is necessary in a control trip circuit, the setting. Unit has a dropout ratio of 65% at minimum setting
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ing seal-in contacts and indicating target which are actuated ICS un� can be replaced by an ACS unit. and 90% at maximum setting.
when the ICS coil is energized at or above pickup current
setting. Su�able for dc control voltages up to and including The ACS unit may be supplied in place of an ICS unit at no
250 volts dc. Two current ranges available: additional cost. Specify system voltage rating on order.
(1) 0.212.0 amps dc, with tapped coil.
( 2) 1.0 amp dc, without taps.
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ASS Power T&D Company Inc. ASS Power T&D Company Inc.
Relay Division Relay Division
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4300 Coral Ridge Drive 7036 Snowdrift Road, Suite 2

....
Coral Springs, FL 33065 • Allentown, PA 18106
954-752-6700 610-395-7333
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December, 1990