Power-Tronics XR5B-400 User manual

© 2018 Power-Tronics, Inc.
The Power-Tronics XR5B-400 Universal Voltage
Regulator is the latest upgrade for all UVR and
XR series specialty voltage regulators. The
XR5B-400 is also capable of replacing other
manufacturers' voltage regulators and has
optional Static Exciter Modules to boost its
capacity to 30 amps DC!
The XR5B-400 is a unique, Universal voltage
regulator that is designed specifically for
Professional Electrical Generator Service
Technicians and the Electrical Generator Repair
Industry. The XR5B-400 is a ruggedized design
and is engineered to provide a lifetime of
trouble-free operation.
The XR5B-400 contains patented electronic
circuitry that allows the installer to match the
regulator's response time to the generator
exciter. This unique innovation eliminates the
need to stock multiple models of regulators and
greatly simplifies installation.
PLC and automated Genset control is possible
with the XR5B-400 by simply adding an optional,
inexpensive digital interface module. This
capability makes the XR5B-400 suitable for
automated or unattended installations, or large-
scale parallel operations.
Like our previous models, the XR5B-400 is fully
repairable! All major electronic components are
not encapsulated to facilitate repair while all
sensitive components are encapsulated to
protect them from contamination and moisture.
The XR5B-400 is compatible with all previous
and current optional modules available for use
with Power-Tronics voltage regulators making it
extremely simple to upgrade an older voltage
regulator installation with the modern features
offered by the XR5B-400.
Specifications
Input Voltage: 120 / 208 or 240vac
Frequency: 400hz
Voltage Regulation: +/- 1% From NL to FL
Parallel Operation Yes
Output Voltage: 0-52vdc @ 120vac input
0-105vdc @ 240vac input
0-210vdc @ 240vac input
Maximum Continuous Output: 5adc
Minimum Field Resistance: 10.5Ω @ 52vdc output
21Ω @ 105vdc output
42Ω @ 210vdc output
Min Residual Build up Voltage: 3.5vac
Under Frequency Protection: No
Physical Size: 4.75 x 6 x 1 in.
Weight: 7 oz
Repairable: Yes
Internal Protection: Fuses, cartridge type
External Voltage Adjustment: Yes
System Operating Indicator: Yes
Optional Static Exciter Modules Yes
Optional External Controls Yes
XR5B-400
400Hz Specialty Series
Universal Voltage Regulator

© 2018 Power-Tronics, Inc.
2
Table of Contents
Introduction and Functional Description:....................................................................3
Determining Which Hookup Configuration to Use:....................................................4
Common 12-Lead Generator Wiring Diagrams:...........................................................6
Use with PMG’s, DPE, AUX, and Harmonic Winding Generators:.............................7
Hookup Connection A:...................................................................................................8
Parallel Configuration for Connection A:.....................................................................9
Hookup Connection B:.................................................................................................10
Parallel Configuration for Connection B:...................................................................11
Hookup Connection C:.................................................................................................12
Parallel Configuration for Connection C:...................................................................13
Initial Setup and Commissioning:...............................................................................14
Optional Power-Tronics Add-On Modules:................................................................15
Conversion From Shunt-Wound to Solid-State Regulation:....................................16
Internal Fuse Replacement:.........................................................................................17
Application Troubleshooting:......................................................................................18
Bench Check Procedures:...........................................................................................19
Installation Warranty Form:.........................................................................................20
Product Warranty Certificate:......................................................................................21

© 2018 Power-Tronics, Inc.
3
Introduction and Functional Description
Caution: Read This Installation
Manual Carefully and Entirely!
Warning: Do not use digital equipment to read voltage, Hz, or amperage
during this installation. Use only Analog sensing equipment! Failure to do so
may result in damage to equipment or in personal injury!
ALWAYS perform all setup procedures off-line
ALWAYS wear eye protection
ALWAYS strip wire insulation properly or use insulated connectors
ALWAYS use analog metering equipment when setting up the regulator
ALWAYS ensure the regulator receives ample airflow
NEVER hold the regulator in your hand when energized
NEVER install the regulator in a place it can get wet or is exposed to the elements
NEVER mount the regulator over a screw, bolt, rivet, welding seam, or other fastener
NEVER remove the regulator cover while the unit is in operation
NEVER insert a screwdriver or other object under the regulator cover
NEVER install a switch in the DC portion of the regulator’s wiring
NEVER USE A DIGITAL FREQUENCY METER (It can give a false reading!)
Functional Description
The XR5B-400 Universal Voltage Regulator is the result of over 20 years of engineering efforts and offers high-
demand features at a competitive price point. The XR5B-400 is a proven design and is engineered to greatly
simplify setup while offering extreme reliability. When properly installed, the XR5B-400 Universal Voltage
Regulator is designed to provide a lifetime of service.
A Generator voltage regulator has several automated tasks it must perform in order to provide reliable, clean,
and regulated electricity. It must build-up the generator, regulate the terminal voltage within its design
specifications, and protect both itself and the generator should a fault situation arise.
The XR5B-400 contains a time-proven, extremely reliable circuit for build-up functionality. Due to its simplicity,
the XR5B-400 is able to build up generators with residual voltages from 3.5VAC without initial overshoot or
excessive delay. The patented circuitry contained in the XR5B-400 allows the user to adjust the regulator to
match the generator’s response time, minimizing setup complexity while maximizing load acceptance and
rejection performance. The XR5B-400 is also a precision voltage regulator and is capable of regulating the
terminal voltage of the generator within +/-1% of its initial set point.
The XR5B-400 uses field-replaceable 20mm glass cartridge fuses to protect its internal circuitry should a fault
occur and the exciter field current exceeds what the regulator is capable of delivering
Due to its extreme simplicity, the XR5B-400 Universal Voltage Regulator is uncommonly reliable and offers
features and regulation accuracy usually only offered by much more complicated and often much more
expensive regulators.

© 2018 Power-Tronics, Inc.
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Determining Which Hookup Configuration to Use
STOP! If you are using an optional SEM250A/B or SE350/450 Static
Exciter Module, DO NOT use these instructions for hookup! See the
instructions that came with your module instead!
The XR5B-400 Universal Voltage Regulator is configurable for 3 different output ranges suitable
for use on the vast majority of generators available on the market from past and present. It is
necessary to choose the proper mode of operation for your generator in order to get the best
regulation and fastest response time possible.
To determine the proper connection for your generator you need to know any two of the
following 3 specifications from the rating plate of your generator:
1: Exciter Field Voltage (in DC Volts) [Generally given in full load Voltage on nameplates]
2: Exciter Field Resistance (in Ohms) [See Note Below]
3: Exciter Field Amperage (in DC Amps) [Generally given in full load Amps on nameplates]
Using the specifications obtained from your generator exciter, select
a Connection (A, B, or C) from the chart below:
• Exciter Field Resistance ≥42Ω & Exciter Full-Load Voltage ≤125VDC
Use connection A (See Page 8)
• Exciter Field Resistance ≥21Ω & Exciter Full-Load Voltage ≤63VDC
Use connection B (See Page 10)
• Exciter Field Resistance ≥10Ω & Exciter Full-Load Voltage ≤32VDC Use
connection C (See Page 12)
Note about Field Resistance:
• When measuring field resistance on a brushless generator, simply measure the resistance of the
exciter field through your field leads with a multimeter.
• When measuring field resistance on a brush-type generator, measure the resistance through both
the field leads as well as directly on the slip rings themselves. The readings you obtain should
ideally be the same, but no more than 1% difference. If you show more than 1% difference in
reading your generator has brush and ring contact problems and will need cleaning or
maintenance before installing the XR5B-400. Failure to correct brush and ring contact
problems will result in severe damage to the voltage regulator as well as possible
PERMANENT damage to the slip rings themselves! NEVER use emery cloth, carborundum
stones, “comm sticks”, or Tuner cleaner to dress or clean slip rings. They will make a bad
problem much, much worse! Only use Garnet or Flint sandpaper and clean with a clean rag
soaked with Acetone for best results!

© 2018 Power-Tronics, Inc.
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If you do not have any of the specifications of your generator’s exciter, or if you
don’t know where to start when trying to determine your exciter specs, please see
the section below for instructions on measuring and calculating your exciter
specifications.
• Measure your exciter field resistance using a multimeter on your field leads.
Record this value. If you have a brush-type generator, also take a resistance
reading on your slip rings: the value you obtain on the slip rings should be no
more than 1% difference from the value you obtained through the field leads.
• Next, start and run the generator and apply 12V from a battery through your
field leads and record the AC voltage produced by the generator. To
determine your full load exciter field voltage, use the following formula:
EExc. =
€
EGen.Conf .
EGen.Output
EBattery
"
#
$
$
%
&
'
'
* 2
Where EGen.Conf. is your Generator’s configured voltage (e.g.: 120, 208, 240,
480V, etc.), EGen.Output is your recorded output voltage, and EBattery is your battery
voltage (12V usually).
• Next, calculate your maximum exciter field amperage using your measured
field resistance and your calculated exciter voltage using the following formula:
I=E
R
Where I is your maximum exciter field current, E is your calculated field
voltage from the above formula, and R is your measured field resistance.
Using the values you just measured and calculated, see the chart on
the previous page to determine which connection you should use to
connect the XR5B-400 to your generator.
For Example:
Measured Field Resistance: 18Ω
Battery Voltage: 12V
Generator Configuration: 480V Wye
12V applied to the field yields 189VAC L1-L3.
EExc. =
480
$%&
$'
∗ 2 = 60.95
EExc. = 60.95VDC (Full-Load Voltage)
This generator would use Connection B.

© 2018 Power-Tronics, Inc.
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Common 12-Lead Generator Wiring Diagrams
Series Wye (416/480V 3ø)
Voltage L-L: 416/480V
Voltage L-N: 240/277V
Voltage CT – N: 120/139V
Parallel Wye (208/240V 3ø)
Voltage L-L: 208/240V
Voltage L-N: 120/139V
NOTE: 208V is Standard Voltage
Series Delta (240V 3ø)
Voltage L-L: 240V
Voltage L1/L2-N: 120V
Voltage L3 – N: 208V
NOTE: L3-N is a “High Leg”
208V instead of 120V!
Double-Delta (120/240V 1ø)
Voltage L-L: 240V
Voltage L-N: 120V
Preferred Single-Phase Connection.
Don’t Use Zig-Zag if Possible.
NOTE: Derate generator by 1/3 rated
capacity when using this connection!

© 2018 Power-Tronics, Inc.
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PMG, DPE Winding, Auxiliary Winding, and
Harmonic/Resonant Winding Use
The XR5B-400 Universal Voltage Regulator is compatible with some of these
types of generators but not others. It is necessary to determine which type of
generator you have before proceeding since some styles will connect differently
than others while the XR5B-400 cannot be used with some of these generators at
all.
PMG (Permanent Magnet Generator/Exciter):
This type of generator generally has a permanent magnet generator mounted on the
main shaft along with a brushless exciter and finally the main rotor itself. The XR5B-
400 is a very fast responding regulator (1/2 cycle response time) and low enough
burden on the main stator that it can be used on these generators without any need for
the PMG input.
To connect the XR5B-400 to this type of generator, isolate and insulate the PMG leads
that were connected to the original voltage regulator. Measure your field resistance and
proceed with sizing on Page 4.
DPE Winding and Auxiliary Winding:
These generators use an extra winding in the main stator as a power supply for the
voltage regulator in an attempt to give the regulator a clean power source that isn’t
affected by load. The XR5B-400 has proprietary filtering circuitry in its sensing stage
that is largely unaffected by generator load. Because the regulator isn’t affected by
loading, these types of windings are not needed.
To connect the XR5B-400 to this type of generator identify, isolate, and insulate the
Auxiliary or DPE wiring that were connected to the original voltage regulator. Measure
your field resistance and proceed with sizing on Page 4.
Harmonic and Resonant Windings:
This type of generator rarely has a voltage regulator, and instead relies on a phase-
shifted “harmonic” winding and a capacitor to adjust the terminal voltage with load.
They often have a brushless “exciter”, but because they operate on harmonics from the
AC waveform, they do not operate like a typical brushless exciter.
Because these generators rely on AC waveform phasing for their voltage
regulation, the XR5B-400 cannot be used with this type of generator.

© 2018 Power-Tronics, Inc.
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Connection A
(See page 9 if the generator will be paralleled using this connection)
Connection A is a Full-Wave rectified configuration, which allows a maximum output of
210VDC @ 5A with an input voltage of 240VAC.
This connection is typically used on higher voltage excitation fields (generally referred to
as 125V fields) or on shunt control fields where the full-load excitation voltage is greater
than 63VDC.
Note that the maximum input voltage to the XR5B-400 Universal Voltage regulator
is 240VAC! DO NOT input 277VAC into the XR5B-400! Severe damage to the unit
will result! For use on 480V systems, either connect the regulator to the winding center
taps T7 and T9 (See Page 6) or use a 480-240V step-down transformer rated at
1.5KVA.
Connecting the input of the XR5B-400 to 2 different legs of the generator as shown in
the diagram below will result in greater regulation accuracy than when connecting line-
neutral.
NOTE:
It is not necessary
to jumper terminals
7 and 8 if not using
the Remote Voltage
Adjustment!
XR5B-400 Specialty Series
Universal Voltage Regulator
NOTE:
If the generator is to be operated below 400 Hz, a disconnect or switch should be installed in
series with the incoming power to terminals #1 and #2 on the XR5B-400.
NEVER install a switch or breaker on the DC or Exciter side of the voltage regulator!
Only install a switch or disconnect on the AC Side of the regulator!
240VAC
MAX!
100K, 2W
Regulator On/Off
Switch
Rate for:
240V @ 10A

© 2018 Power-Tronics, Inc.
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Parallel Configuration for Connection A
To use the XR5B-400 Universal Voltage Regulator in a parallel configuration either with
another generator or with a buss such as a utility, use the diagram below for proper
hookup with the XR5B-400 configured for Connection A.
NOTE: Power-Tronics products parallel using the Reactive Droop compensation method. This allows
our products to parallel with existing systems easily while also allowing islanded operation with the flip of
a switch. When initially installing the droop resistor, set it for approximately 3Ω before final adjustment
later. If the droop is excessive when load testing, reduce the resistance a bit at a time until satisfactory
droop is achieved. CT should be sized at 25-35VA burden!
XR5B-400 Specialty Series
Universal Voltage Regulator
240VAC
MAX
Secondary
Voltage!
100K, 2W
Unit/Parallel
Switch
Reactive Droop
Adjustment
10Ω, 100W
CT Rating:
XXX/5A @ 25-35VA
Transformer
Rating:
XXX:240V
@ 1.5KVA
Regulator On/Off
Switch
Rate for:
Primary Voltage
@ 10A
Setup Tips:
•Isolation Transformer is
recommended for best
results, but is optional if
208/240V is present on
generator.
•Size CT as closely to rated
generator output amperage
as possible for best
paralleling results. An
oversized CT will result in
poor paralleling or loss of
control!
•If generator terminal voltage
rises, or if generator exports
VARS excessively under
load, reverse CT leads.
•If the reactive droop
resistor/rheostat gives
erratic results or
inconsistent resistance,
lightly sand the exposed
wire with 400 grit sandpaper
to improve connection
between wire and slider.

© 2018 Power-Tronics, Inc.
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Connection B
(See page 11 if the generator will be paralleled using this connection)
Connection B is a Half-Wave rectified configuration, which allows a maximum output of
105VDC @ 5A with an input voltage of 240VAC.
This connection is typically used on a majority of brushless generator excitation fields
(generally referred to as 63V fields) or on shunt control fields where the full-load
excitation voltage is greater than 32VDC, but less than or equal to 63VDC.
Note that the maximum input voltage to the XR5B-400 Universal Voltage regulator
is 240VAC! DO NOT input 277VAC into the XR5B-400! Severe damage to the unit
will result! For use on 480V systems, either connect the regulator to the winding center
taps T7 and T9 (See Page 6) or use a 480-240V step-down transformer rated at
1KVA.
Connecting the input of the XR5B-400 to 2 different legs of the generator as shown in
the diagram below will result in greater regulation accuracy than when connecting line-
neutral.
NOTE:
It is not necessary
to jumper terminals
7 and 8 if not using
the Remote Voltage
Adjustment!
XR5B-400 Specialty Series
Universal Voltage Regulator
NOTE:
If the generator is to be operated below 400 Hz, a disconnect or switch should be installed in
series with the incoming power to terminals #1 and #2 on the XR5B-400.
NEVER install a switch or breaker on the DC or Exciter side of the voltage regulator!
Only install a switch or disconnect on the AC Side of the regulator!
240VAC
MAX!
100K, 2W
Regulator On/Off
Switch
Rate for:
240V @ 10A

© 2018 Power-Tronics, Inc.
11
Parallel Configuration for Connection B
To use the XR5B-400 Universal Voltage Regulator in a parallel configuration either with
another generator or with a buss such as a utility, use the diagram below for proper
hookup with the XR5B-400 configured for Connection B.
NOTE: Power-Tronics products parallel using the Reactive Droop compensation method. This allows
our products to parallel with existing systems easily while also allowing islanded operation with the flip of
a switch. When initially installing the droop resistor, set it for approximately 3Ω before final adjustment
later. If the droop is excessive when load testing, reduce the resistance a bit at a time until satisfactory
droop is achieved. CT should be sized at 25-35VA burden!
XR5B-400 Specialty Series
Universal Voltage Regulator
240VAC
MAX
Secondary
Voltage!
100K, 2W
Unit/Parallel
Switch
Reactive Droop
Adjustment
10Ω, 100W
CT Rating:
XXX/5A @ 25-35VA
Transformer
Rating:
XXX:240V
@ 1KVA
Regulator On/Off
Switch
Rate for:
Primary Voltage
@ 10A
Setup Tips:
•Isolation Transformer is
recommended for best
results, but is optional if
208/240V is present on
generator.
•Size CT as closely to rated
generator output amperage
as possible for best
paralleling results. An
oversized CT will result in
poor paralleling or loss of
control!
•If generator terminal voltage
rises, or if generator exports
VARS excessively under
load, reverse CT leads.
•If the reactive droop
resistor/rheostat gives
erratic results or
inconsistent resistance,
lightly sand the exposed
wire with 400 grit sandpaper
to improve connection
between wire and slider.

© 2018 Power-Tronics, Inc.
12
Connection C
(See page 13 if the generator will be paralleled using this connection)
Connection C is a Half-Wave rectified configuration, which allows a maximum output of
52VDC @ 5A with an input voltage of 120VAC.
This connection is typically used on low voltage excitation fields (generally referred to as
32V fields) or on shunt control fields where the full-load excitation voltage is less than
32VDC.
Note that the maximum input voltage to the XR5B-400 Universal Voltage regulator
is 139VAC in this configuration! DO NOT input 240VAC into the XR5B-400!
Severe regulation problems may result! For use on 480V systems, either connect the
regulator to the winding center taps T7 to T0 (See Page 6) or use a 480-120V step-
down transformer rated at 500VA (Preferred for superior regulation accuracy).
Connecting the input of the XR5B-400 to 2 different legs of the generator through a
transformer will result in greater regulation accuracy than when connecting line-neutral
as shown in the diagram below.
NOTE:
It is not necessary
to jumper terminals
7 and 8 if not using
the Remote Voltage
Adjustment!
XR5B-400 Specialty Series
Universal Voltage Regulator
NOTE:
If the generator is to be operated below 400 Hz, a disconnect or switch should be installed in
series with the incoming power to terminals #1 and #2 on the XR5B-400.
NEVER install a switch or breaker on the DC or Exciter side of the voltage regulator!
Only install a switch or disconnect on the AC Side of the regulator!
139VAC
MAX!
100K, 2W
Regulator On/Off
Switch
Rate for:
240V @ 10A

© 2018 Power-Tronics, Inc.
13
Parallel Configuration for Connection C
To use the XR5B-400 Universal Voltage Regulator in a parallel configuration either with
another generator or with a buss such as a utility, use the diagram below for proper
hookup with the XR5B-400 configured for Connection C.
NOTE: Power-Tronics products parallel using the Reactive Droop compensation method. This allows
our products to parallel with existing systems easily while also allowing islanded operation with the flip of
a switch. When initially installing the droop resistor, set it for approximately 3Ω before final adjustment
later. If the droop is excessive when load testing, reduce the resistance a bit at a time until satisfactory
droop is achieved. CT should be sized at 25-35VA burden!
XR5B-400 Specialty Series
Universal Voltage Regulator
120VAC
MAX
Secondary
Voltage!
100K, 2W
Unit/Parallel
Switch
Reactive Droop
Adjustment
10Ω, 100W
CT Rating:
XXX/5A @ 25-35VA
Transformer
Rating:
XXX:120V
@ 500VA
Regulator On/Off
Switch
Rate for:
Primary Voltage
@ 10A
Setup Tips:
•Isolation Transformer is
recommended for best
results even if 120/139V is
present on generator.
•Size CT as closely to rated
generator output amperage
as possible for best
paralleling results. An
oversized CT will result in
poor paralleling or loss of
control!
•If generator terminal voltage
rises, or if generator exports
VARS excessively under
load, reverse CT leads.
•If the reactive droop
resistor/rheostat gives
erratic results or
inconsistent resistance,
lightly sand the exposed
wire with 400 grit sandpaper
to improve connection
between wire and slider.

© 2018 Power-Tronics, Inc.
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Initial Setup and Commissioning
1. Install the regulator according to the correct wiring diagram (Connection A, B, or C).
2. If installing the XR5B-400 on a brush-type generator, verify that the brushes and brush riggings
are isolated, ungrounded, and connected ONLY to the XR5B-400.
3. Turn the internal controls 15 or more turns counter clockwise (left) or until you hear the screws
click. This procedure is necessary in case the original factory settings have been altered.
4. If you are using a remote voltage adjustment, set it at 50% of adjustment.
5. If the generator is to be paralleled, set the droop resistor between 2Ω and 3Ω.
6. Start up the prime mover and bring up to operating speed and turn on the regulator switch (if
used).
7. Set the internal voltage adjustment to the desired voltage setting for the generator output by
turning the adjustment screw clockwise (right).
Note that the voltage adjustment is a 25-turn pot! You may notice unsteady or pulsating
voltage. If so turn the Stability adjustment clockwise until the pulsation stops. As you turn the
stability adjustment, the terminal voltage will rise. Always keep your voltage within 10%
of the desired setpoint with your voltage adjustment.
8. Place the generator on line and observe the frequency and voltage.
9. If the generator is being paralleled, measure the droop during loading and adjust the droop
resistor as necessary. Reducing droop resistor resistance will reduce droop.
NOTE: Loading the generator with a purely resistive load-bank may cause undesirable
droop characteristics such as no droop, very slight droop, or even rising terminal
voltage. Measure droop with a mixed load for best results.
10. If paralleling and the terminal voltage rises or excessive amperage exportation occurs during
loading with a mixed load connected, reverse the CT leads and try again.
11. Observe voltage regulation during no-load and full-load conditions. Once the voltage is set and
regulating characteristics are satisfactory the installation procedure is complete.
Internal
voltage
adjustment
System
indicator light
Stability
adjustment

© 2018 Power-Tronics, Inc.
15
Optional Power-Tronics Add-On Modules
Power-Tronics offers a wide array of optional add-on modules for the XR series
voltage regulators from static exciter modules to digital interface cards. For more
information on any of the modules below, visit our online catalog at:
www.power-tronics.com
SEM250A
Static Exciter Module
Converts the XR5B-400 into a
63VDC 25ADC Static Exciter!
SEM250B
Static Exciter Module
Converts the XR5B-400 into a
125VDC 25ADC Static Exciter!
EIC1020
External Interface Card
Allows the XR5B-400 to be
controlled externally by virtually
any digital load-sharing controller,
VAR controller, genset controller,
or digital governor controller!
MOP1224HD
Motorized Potentiometer
Allows the XR5B-400 to be
externally controlled by older
automated controllers using
pulsed signals or dry contacts
for control!
ABF10
Automatic Battery Flash
Adds Automatic Battery Flash
to installations with low residual
or requiring guaranteed buildup!
AFM5X
Automatic Flash Module
Adds Automatic Flash or
Battery Flash to installations
with low residual or requiring
guaranteed buildup!

© 2018 Power-Tronics, Inc.
16
Conversion From Older Shunt-Wound Voltage
Regulation to Modern Solid-State Voltage Regulation
It is possible to use the XR5B-400 Universal Voltage regulator with older Shunt-Wound
exciters that originally had manual or mechanical voltage regulators by converting the
wiring as in the diagrams below. If the generator will not build up after conversion, try
switching your F+ and F- leads at the regulator and try starting up again.
NOTE:
Armature brushes
MUST BE ISOLATED
from the field leads for
proper operation!

© 2018 Power-Tronics, Inc.
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Fuse Replacement
The XR5B-400 contains two 20mm cartridge fuses located for quick and convenient
replacement should they blow. To replace the fuses, follow the instructions below.
Fuse size is 20mm x 5mm rated at 5A at 250VAC.
Power-Tronics Part Number: 5R3-403 (Comes as a package of 10 fuses)
Cooper-Bussmann Part Number: BK/GDB-5A
Fuse Replacement Procedure:
(Refer to the image above for easy reference)
• Remove the 4 screws holding the mounting can to the circuit board.
• Separate the regulator printed circuit card from the mounting housing.
• Replace open fuses then replace and replace and tighten all screws.
• Fuse size is 20mm x 5mm, 5A @ 250VAC. (DO NOT REPLACE WITH ANY
OTHER TYPE OR RATING OF FUSE! YOU WILL VOID YOUR WARRANTY
AND SEVERE DAMAGE AND PERSONAL INJURY COULD RESULT BY
DOING SO!)
Fuses, 20 x 5mm,
5 amp @ 250vac

© 2018 Power-Tronics, Inc.
18
Application Troubleshooting
Problem: Possible Cause
No Voltage 1 3 5 7 9 11 13 15 20
Pulsating Voltage 4 5 6 12 16
Flickering Voltage 4 6 7 14
High Voltage 6 7 8 9 12 13 17 18 20
Voltage Drop on Load 5 8 10 12 16
Low Voltage 5 8 12 13
Poor Voltage Regulation 2 4 10 12 13 16
No Voltage Control 13 19 20
Possible Causes:
1. Residual input voltage to the voltage regulator is below 3.5vac or fuses are open in the regulator.
2. Unbalanced generator load.
3. Open exciter field or defective generator.
4. Non linear load or defective connection in exciter field.
5. Open diode in exciter or shorted rotor in generator.
6. Stability adjustment is not properly adjusted or loose component in voltage regulator.
7. Loose wiring connections.
8. Input voltage to regulator is too low.
9. Exciter field is grounded.
10. Non linear load, stability control too far clockwise, or wrong selection for regulator hookup.
11. Exciter fields are reversed.
12. Wrong selection of regulator wiring configuration.
13. Defective voltage regulator.
14. SCR or Inverter drive effecting generator waveform.
15. Regulator needs external flashing circuit.
16. Isolation transformer is too small.
17. Isolation transformer is needed.
18. Exciter fields are not isolated from other circuits.
19. Input and field circuit are being fed by a common cable or conduit.
20. Incorrect hookup or wiring.

© 2018 Power-Tronics, Inc.
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Bench Check Procedures
1. Wire the regulator as shown in Figure A below.
2. Connect a 120 volt 50 to 150 watt light bulb as shown.
3. Adjust the internal voltage pot fully CCW (25 turns) or until a click is heard.
4. Input 120vac into the regulator at #1 and #2. (Fuse this input with fuses rated at 120 volts or
higher and not more than 5 amps)
5. Observation: The green status light should be on and the incandescent light bulb should be off.
If the green status light is not on, the internal fuses are blown in the regulator or there is
internal damage to the regulator! If the green status light is not on, do not continue this test!
6. SLOWLY turn the internal voltage adjustment CW until the incandescent light bulb turns fully on,
then adjust the internal voltage adjustment CCW until the light bulb is off.
7. Observation: You should be able to taper the incandescent light bulb on and off in a relatively
smooth manner. If the light flashes on or off quickly, the regulator has an internal fault, do
not continue this test!
8. Remove the 120vac from the regulator.
9. Reconnect the regulator as shown in Figure B and perform all of the previous steps again. In
this mode, the light bulb will only glow at half brightness!
10. If you were able to successfully perform all of these tests, the regulator is good. IF ANY
SINGLE STEP FAILED, THE REGULATOR IS DEFECTIVE!
Figure A
120V 50-150W
Incandescent
Figure B
120VAC
Fused
@ 5A
120V 50-150W
Incandescent
120VAC
Fused
@ 5A

© 2018 Power-Tronics, Inc.
20
Installation Warranty Form
It is very important that you fill out this form completely when installing a voltage regulator. This form
serves as a history record on the application. This form also contains the information needed by
Power-Tronics, Inc., for repair and troubleshooting of any product you may be having problems with.
Failure to fill out this form during installation will result in a cancellation of your warranty
coverage! Filling out this form takes only minutes but will save hours or days later on if your
product should require service!
Problem Description/History (Please be detailed!!!):
Ship-To Address (City, State, Zip, Country):
Company Name:
Contact Person:
Telephone Number:
Email Address:
Primary Load (Please Explain):
Repair/Warranty Request Information
Generator Leads (Check One:) ☐12 ☐10 ☐6 ☐4 (3ø) ☐4 (1ø) ☐3
Generator Wiring Mode (Check One:) ☐High-Wye ☐Low-Wye ☐Series Delta
☐Zig-Zag ☐Double-Delta ☐Single-Phase ☐Other
Terminal Voltage:
Residual AC Voltage:
Rated KW:
Rated KVA:
Generator Wiring/Usage Information
This Section for Brushless Generators Only
Exciter Field Voltage:
Exciter Field Resistance:
This Section for Brush-Type Generators Only
Shunt-Field Voltage:
Shunt-Field Resistance:
Rotor Resistance @ Brush Leads:
Rotor Resistance on Slip-Rings:
Rotor Excitation Voltage:
Product Model:
Serial #:
Date of Installation:
Additional Module(s) or Options: