INSTRUCTION MANUAL

FOR
VOLTAGE REGULATOR
Model: AEC 42- 7
Part Number: 9 2709 00 100

Publication Number: 9 2709 00 990

Revision: F 12/99
 INTRODUCTION
This manual provides information concerning the operation and installation of AEC42-7 Voltage
Regulators. To accomplish this, the following is provided.
• Specifications
• Installation
• Operation
• Maintenance

WARNING!
TO AVOID PERSONAL INJURY OR EQUIPMENT DAMAGE, ONLY QUALIFIED
PERSONNEL SHOULD PERFORM THE PROCEDURES PRESENTED IN THIS
MANUAL.

AEC 42-7 Introduction i

 First Printing: January 1993

Printed in USA

© 1998 Basler Electric Co., Highland, IL 62249

December 1999

CONFIDENTIAL INFORMATION
OF BASLER ELECTRIC COMPANY, HIGHLAND, IL. IT IS LOANED FOR
CONFIDENTIAL USE, SUBJECT TO RETURN ON REQUEST, AND WITH THE
MUTUAL UNDERSTANDING THAT IT WILL NOT BE USED IN ANY MANNER
DETRIMENTAL TO THE INTEREST OF BASLER ELECTRIC COMPANY.

It is not the intention of this manual to cover all details and variations in equipment, nor
does this manual provide data for every possible contingency regarding installation or
operation. The availability and design of all features and options are subject to
modification without notice. Should further information be required, contact Basler Electric
Company, Highland, Illinois.

BASLER ELECTRIC
ROUTE 143, BOX 269
HIGHLAND, IL 62249 USA
http://www.basler.com, info@basler.com
PHONE 618-654-2341 FAX 618-654-2351
ii AEC 42-7 Introduction
 CONTENTS

SECTION 1 GENERAL INFORMATION ...................................................................................... 1-1

Description................................................................................................................. 1-1
Specifications ............................................................................................................ 1-1
Frequency Compensation ......................................................................................... 1-2
Over-excitation Time Delay ....................................................................................... 1-2

SECTION 2 INSTALLATION ........................................................................................................ 2-1

Mounting.................................................................................................................... 2-1
Exciter Field Power Circuit ........................................................................................ 2-2
Power Input ............................................................................................................... 2-3
Sensing Inputs........................................................................................................... 2-3
Quadrature Droop Input............................................................................................. 2-3
Fuses......................................................................................................................... 2-3
Voltage Adjust Rheostat (V) ...................................................................................... 2-3
V/Hz “Corner Frequency” Selection .......................................................................... 2-3
Overexciation Shutdown............................................................................................ 2-3

SECTION 3 OPERATION ............................................................................................................. 3-1

General...................................................................................................................... 3-1
Preliminary set-up...................................................................................................... 3-1
System set-up............................................................................................................ 3-2
Field Flashing ............................................................................................................ 3-2

SECTION 4 MAINTENANCE ........................................................................................................ 4-1

Preventive maintenance ............................................................................................ 4-1

Operational Test ........................................................................................................ 4-1

SECTION 5 MANUAL CHANGE INFORMATION........................................................................ 5-1

Changes .................................................................................................................... 5-1

AEC 42-7 Introduction iii

SECTION 1 • GENERAL INFORMATION
DESCRIPTION
The AEC 42-7 voltage regulator is designed for use on 50/60 Hz brushless generators. The regulator
includes frequency compensation, over excitation shutdown, a solid-state build-up circuit, and EMI
filtering.

SPECIFICATIONS
Refer to Table 1-1 for the electrical specifications of the AEC 42-7 and to Table 1-2 for the physical
specifications

Table 1-1. Electrical Specifications

Dc Output Power: 7 Adc at 42 Vdc maximum continuous.

15 Adc at 90 Vdc forcing for 10 seconds.
(at 240 Vac supply voltage).
Exciter Field
Dc Resistance: 6 Ohms minimum, 105 Ohms maximum.

Ac Power Input: Operating range 220 Vac to 260 Vac, 1-Phase, 50/60 Hz, <900 VA
Burden.
Sensing Input: 200-252 Vac ±10%, 2-Phase, 50/60 Hz. <1 VA Burden.

Voltage Adjust Range: 180-277 Vac.

Regulation Accuracy: <1% No-load to Full-load, Average Sensing.

Paralleling: Input for 5 Vac from External C.T./Burden Resistor to allow 10%
Droop.
Response Time: Less than 1.5 cycles for ±5% change in sensing voltage.
Link (T C) and Adjustable Stability to optimize response.
EMI Suppression: Internal EMI filter.

Frequency
Compensation: Twice Volts per Hertz (See Figure 1-1 for curve).

Over-excitation Inverse Time delayed, fixed setting. Trip range from no trip @ 50
Shutdown: Vdc to instantaneous at 100 Vdc. (See Figure 1-2 for curve).
Disable link terminals (N D) provided for parallel operation.
Voltage build-up: Internal provision for automatic build-up from 6 Vac, ‘Soft Start’.

Power Dissipation: 20 Watts typically.

AEC 42-7 General Information 1-1

 Table 1-2. Physical Specifications

Operating Temperature: -20°C (-4°F) to 60°C (140°F)

Storage Temperature: -40°C (-40°F) to 85°C (185°F)

Vibration: Withstands 1.3 G's at 2 to 27 Hz.; 0.036" double amplitude at 27 to

52 Hz.; and 5 G's at 52 to 1000 Hz.
Shock: Withstands up to 20 G's in each of three mutually perpendicular
axes.
Weight: 0.68 kg. (1.5 lbs)

FREQUENCY COMPENSATION (See Figure 1-1)

The frequency compensation characteristic of Figure 1-1 is used to improve system load pickup perfor-
mance by restraining voltage recovery until frequency has also started to recover.
The regulator is shipped from the factory set at a 47 Hz ‘corner frequency’ for 50 Hz systems. For 60 Hz
systems, a 57 Hz corner frequency is achieved by removing the ‘50-50’ external link.

Figure 1-1. Frequency Compensation Curves

OVER-EXCITATION TIME DELAY

If exciter field voltage exceeds 52 ± 2 Vdc, the regulator automatically removes the field current, after a
time delay. The time delay is inversely proportional to the magnitude of the detected field over voltage
condition up to 95 ±5 Vdc point. Beyond 95 ±5 Vdc, the field voltage is removed at a much faster rate.
This shutdown function may be disabled for parallel operation by linking terminals N and D together.

1-2 AEC 42-7 General Information

 Figure 1-2. Typical Inverse Time Delay Characteristic Curve

AEC 42-7 General Information 1-3

SECTION 2 • INSTALLATION
MOUNTING
The regulator may be mounted on the generator in any convenient position. Refer to outline drawing
Figure 2-1. Figure 2-2 provides the drilling template.

NOTE
The ground terminal must be bonded either to a metal ground by the mounting screw or
by means of a cable to the most suitable earthing point available close to the regulator.

Figure 2-1. AEC 42-7 Outlined Diagram

AEC 42-7 Installation 2-1

 Figure 2-2. Drilling Template.

EXCITER FIELD POWER CIRCUIT

Connect regulator + wire to the brushless exciter field F+ terminal, and the - wire to the field F- terminal.
Refer to Figure 2-3.
CAUTION
The DC resistance of the exciter field must be equal to or greater than 6 ohms and less than
100 ohms.

If the exciter field resistance is less than 6 ohms, and if the full-load field current does not exceed the
maximum continuous current rating of the regulator (7 Adc), a resistor of sufficient wattage must be added
in series with the field to bring the total resistance to 6 ohms.

Figure 2-3. Interconnection Diagram, 480 Vac Generator

2-2 AEC 42-7 Installation

POWER INPUT
Connect wiring as shown in Figure 2-3. Power for the regulator is derived from the generator auxiliary
winding, connected to wires 3 and 4. The operable power input range is 220-260 Vac.

SENSING INPUTS
For sensing, wires U and V are connected to the generator phase U and phase V respectively. Wires X
and Y are connected to the opposite ends of the U and V phase coils, or commoned together at the
Neutral (star) point.

QUADRATURE DROOP INPUT

When paralleling is required, a current transformer (C.T.) and variable burden resistor (rheostat) should be
connected to terminals A and B. The ratio of the C.T. and the maximum value of the burden must be
chosen so that at maximum current the voltage applied to terminals A and B does not exceed 5 Vac rms.
A suitable value of burden would be a rheostat adjustable from 0 - 5 ohms (10 Watts) for a C.T. with a 1
Aac secondary current at full load. These terminals may either be linked or left open when paralleling is
not required.

FUSES
It is recommended that a fuse or fuses with high interruption capability be installed per the interconnection
diagram. A suitable fuse type would be Littlefuse type 3AG, rated 250 Vac, 6,3 A, ‘SLO-BLO’.
Dimensions are 6.3 mm x 32 mm (1¼" x ¼").

NOTE
Fuse(s) MUST be installed per interconnection diagram to avoid interrupting field current
directly.

VOLTAGE ADJUST RHEOSTAT (V)

An internal screw-driver pre-set (V) provides coarse adjustment of generator output voltage. Adjustment
of V clockwise increases voltage.
The voltage regulator is shipped from the factory with a link across terminals P and Q. If a remote voltage
adjust rheostat is used, the link should be removed and the Rheostat connected to P and Q. A 1 kilohm,
0.5W. potentiometer will provide a ‘fine’ voltage range adjustment of approximately ±10 % over most of the
coarse range of adjustment. See Figure 2-3 interconnection diagram.

V/Hz "CORNER FREQUENCY" SELECTION

For 50 Hz systems, the regulator is pre-set at the factory for a 47 Hz "corner frequency", and a link fitted
across terminals ‘50’. If operation at 60 Hz is required, this link should be removed; the "corner frequency"
is now set to 57 Hz. Do not operate the system at 60 Hz with the 50 Hz link still in place.

AEC 42-7 Installation 2-3

OVER-EXCITATION SHUTDOWN
Over-excitation shutdown is provided to remove output excitation should the regulator's output voltage
exceeds 52 ± 2 Vdc for a sufficient time. The inverse-time-delay curve is shown in Figure 1-2. For
voltages above 95 ±5 Vdc, there is a second and much shorter inverse time curve.
After output power is removed, the regulator can be reset by decreasing the input voltage to less than 6
Vac for a minimum of 2 seconds; this may be accomplished by stopping the prime mover or interrupting
the regulator input by means of a reset switch.
In cases where the generator is operating in a parallel mode, it is sometimes considered undesirable to
allow the regulator to shut down, which may cause the generator to be ‘motored’. The regulator is provid-
ed with terminals N and D, which may be linked together to prevent over-excitation shutdown. Note
however that continuous running at output levels greater than the continuous rating may result in eventual
regulator failure, and that other means should be employed to protect the system.

2-4 AEC 42-7 Installation

SECTION 3 • OPERATION
GENERAL
CAUTION
Meggers and high-potential test equipment must not be used. Incorrect use of such
equipment could damage the semiconductors used in the regulator.

The following system operation procedures provide instructions for adjusting the AEC 42-7 voltage
regulator. Symptoms resulting form a faulty regulator and certain generator system problems are
included, together with suggested remedies.
Complete the following steps before proceeding with system start-up.

PRELIMINARY SET-UP
a. Verify that the voltage regulator specifications conform with the generator system requirements.
b. Ensure that the regulator links are fitted correctly where required, as follows:-
(1) If the remote voltage adjust rheostat is not required, ensure terminals P and Q are linked together.
(2) If a 57 Hz corner frequency for 60 Hz systems is desired, ensure the ‘50 - 50’ link is removed. If a
47 Hz corner frequency for 50 Hz systems is desired, ensure the ‘50 - 50’ link is connected.
(3) If the system is to be run in parallel, consider whether shutdown of the generator's excitation is
acceptable. If not, ensure that the link between terminals N and D is in place.
c. Ensure the voltage regulator is correctly connected to the generator system; F+ to field positive, F- to
field negative, and terminals 3 and 4 to the auxiliary winding supply. It is vital that the sensing connec-
tions are correctly made to all 4 wires U, V, X, and Y. Ensure the metal ring tag at one mounting hole
is bonded to ground via either a metal screw or short length of cable.
d. Install the fuses as directed in the previous section.
e. Set the regulator and external voltage adjust, if used, as follows:
Regulator Volts Adjust ‘V’ Fully CCW
Remote Volts Adjust Centered
Stability Adjust ‘S’ Centered

AEC 42-7 Operation 3-1

SYSTEM START-UP
a. Perform preliminary set-up, per paragraph 3-2, checking wiring carefully.

NOTE
All AC voltage readings are to be taken with an ‘average’ reading voltmeter

b. Start Prime-mover and bring up to rated speed.

RESULT: Voltage should build up to less than nominal value. If not, proceed to paragraph 3-4.
c. Slowly adjust the regulator voltage adjust V until the generator output voltage reaches the nominal
value. Should a low frequency oscillation or hunting be present on the generator output voltage,
adjust stability control S to cause this to be damped out. In general, ‘Clockwise’ increases the stability
but in some cases, too far CW may start to reduce stability again, and will invariably slow the
response of the generator to load changes. An optimum method of setting is to adjust S slowly CCW
until the generator voltage just starts to become unstable, then up to ¼ turn CW from that position.
d. If used, adjust the external voltage adjust rheostat to fine trim the voltage to the exact value desired.
RESULT: Voltage should now have built up and be stable at the desired value. If voltage does not build
up to rated value, check that there is no short circuit or excessive load present on the genera-
tor lines. If a minimum residual of 6 Vac is not present, perform ‘field flashing’ per paragraph
3-.4.
e. Check regulator under normal operating and loading conditions.
RESULT: Voltage regulation should be better than ±1.0% no-load to full-load. If regulation is not within
this range, check the following:
(1) Voltage reduction under loads of cosq>0.0 may be due to speed reduction due to loading of the
prime mover. This may be causing the frequency compensation (V/Hz) circuit to reduce voltage
at a speed which is less than the "corner frequency".
(2) Replace voltage regulator.

FIELD FLASHING
When the regulator is operated with the generator for the first time, the polarity of residual magnetism may
be reversed or too small to achieve the necessary build-up voltage for the regulator. If reversing the field
connections does not induce build-up, and the residual voltage is less than the specified value of 6 Vac,
shut down the Prime-mover and proceed with the following steps:
a. With the Prime-mover at rest and the regulator's field output wires disconnected, apply a DC source
(NOT grounded) of not more than 24 Vdc with Positive to F+ and Negative to F-, in series with a
current-limiting resistor of 3-5 ohms. (The set battery is a suitable source.)
b. Allow approximately 3 seconds before removing the DC source.
c. With the voltage regulator disconnected (wires 3 and 4), start the prime mover and measure the
‘residual’ voltage available at the auxiliary winding. If this voltage is greater than 6 Vac, reconnect
voltage regulator, and voltage build-up should be successful. If less than 6 Vac is measured, repeat
field flashing procedure.
d. If repeating steps a. and b. does not result in generator voltage build-up, and residual is greater than 6
Vac, replace voltage regulator.

3-2 AEC 42-7 Operation

SECTION 4 • MAINTENANCE
PREVENTIVE MAINTENANCE
A periodic inspection of the unit should be made to ensure it is kept clean and free from accumulations of
dust and moisture. It is vital to ensure that all the wire and terminal connections are kept sound, secure
and free from corrosion.

OPERATIONAL TEST
a. Connect the test set-up as shown in Figure 4-1. Do NOT apply power. Ensure the light bulbs are rated
120 volts and less than 100 Watts. Alternatively a single 240 V bulb may be used.

WARNING
If a glass fuse is used, it is advisable to enclose it for safety.

b. Adjust the internal (V) and external voltage adjust potentiometers fully CCW.
c. Apply 240 Vac, 50/60 Hz power to the regulator.
d. Slowly turn the internal voltage adjust V in the CW direction.
RESULT: 1) Before fully CW is reached, the light bulb should reach full brilliance to signify the regulator
is controlling correctly.
2) At this ‘regulating point’, a small change in either of the adjustments should result in the
light bulb being turned full on or off.

Figure 4-1. Test Set-up Diagram

AEC 42-7 Maintenance 4-1

SECTION 5 • MANUAL CHANGE INFORMATION
CHANGES
Substantive changes in this manual to date are summarized in Table 5-1.

Table 5-1. Summary of Changes

Revision Summary of Changes ECO No. Date

E Changed the format of the manual. Corrected Figure 2-3 caption 1281 11-98
from “240 Vac Generator” to “480 Vac Generator.”

F Page 2-3, Voltage Adjust Rheostat (V), changed reference for 7600 12-99
Figure 2-2 to Figure 2-3.

AEC 42-7 Manual Change Information 5-1