Power-Tronics SEM100A User manual

© 2012 Power-Tronics, Inc.
The Power-Tronics SEM100A Static
Exciter Module is a self-contained
external rectifier assembly for all
Power-Tronics XR and UVR series
voltage regulators. The SEM100A
Static Exciter Module allows a
standard Power-Tronics voltage
regulator to control exciter fields with
current requirements up to 100 amps
DC at 105VDC!
The SEM100A is a unique design,
intended to offer the capacity of a full
static exciter while reducing its
physical footprint for installations with
space restrictions.
The SEM100A is a very robust design
and is intended to operate for a
lifetime. However, should repair ever
be necessary, the SEM100A is
extremely simple to repair, minimizing
downtime!
The SEM100A Static Exciter is
compatible with all Power-Tronics
UVR, XR, and certain older VR series
voltage regulators, as well as the
Power-Tronics PC500X, UVR500PC,
and XR500PC phase controllers!
Specifications
Input Voltage: 208-240vac
Frequency: N/A
Output Voltage: 0-105vdc @ 240vac input
Maximum Continuous Output: 90adc
Maximum Forcing Output: 100adc
Minimum Field Resistance: 1.05Ω@ 105vdc output
Physical Size: 10 x 10 x 8 in.
Weight: 8 lbs
Repairable: Yes
SEM100A
Static Exciter Module

© 2012 Power-Tronics, Inc.
2
Table of Contents
Introduction and Functional Description:....................................................................3
Determining Application Sizing:...................................................................................4
Hookup Diagram:............................................................................................................6
Parallel Hookup Diagram:..............................................................................................7
Initial Setup and Commissioning:.................................................................................8
Optional Power-Tronics Add-On Modules:..................................................................9
Application Troubleshooting:......................................................................................10
Bench Check Procedures:...........................................................................................11
Installation Warranty Form:.........................................................................................12
Product Warranty Certificate:......................................................................................13

© 2012 Power-Tronics, Inc.
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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 exciter
ALWAYS ensure the exciter receives ample airflow
ALWAYS use adequate fusing
NEVER hold the regulator in your hand when energized
NEVER install the exciter in a place it can get wet or is exposed to the elements
NEVER mount the exciter over a screw, bolt, rivet, welding seam, or other fastener
NEVER insert a screwdriver or other object into any part of the SEM100A
NEVER touch any exposed part of the SEM100A during operation
NEVER install a switch in the DC portion of the exciter’s wiring
NEVER USE A DIGITAL FREQUENCY METER (It can give a false reading!)
Functional Description
The SEM100A Static Exciter Module has a proven track record of over 20 years of
extreme reliability and robustness. It offers an inexpensive and unique way to upgrade
a standard voltage regulator to a reduced size static exciter with a minimum of
connections and a minimum of installation space.
The SEM100A is designed to work with Power-Tronics UVR and XR series voltage
regulators and UVR, XR, and PC series phase controllers. Coupled with one of these
products, the SEM100A allows field excitation of 105VDC at 90ADC continuous.
Regulation accuracy depends on the voltage regulator the SEM100A is used with. If
used with the XR500D series Universal Voltage Regulator, the voltage regulation will be
within +/-.25%. Other voltage regulators will regulate within their printed specifications.
The SEM100A does not contain internal fusing and must be fused externally.
Always use 100A 250VAC fast-blow fuses (such as JJN or Type J fuses) with the
SEM100A Static Exciter Module! Failure to fuse the SEM100A properly will void
your warranty!

© 2012 Power-Tronics, Inc.
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Determining Application Sizing
STOP! DO NOT use the instruction manual that came with your
voltage regulator when using the SEM100A Static Exciter Module!
Use this manual instead! It contains the most up to date information
available regarding your product!
The SEM100A Static Exciter Module is designed for use with 208-240VAC input. It contains
internal suppression for use with brush-type generator sets. Before installation, it is necessary
to verify that the SEM100A is the correct product for your application.
To determine if the SEM100A is the correct product 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,
verify that your generator fits the specifications from the chart or
graph below:
•Exciter full load voltage is 63VDC or less, and your exciter field resistance is
1.05Ωor greater.

© 2012 Power-Tronics, Inc.
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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 SEM100A. 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!
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 Iis your maximum exciter field current, Eis your calculated field
voltage from the above formula, and Ris your measured field resistance.
Using the values you just measured and calculated, see the chart on
the previous page to determine whether the SEM100A is the correct
product for your application.

© 2012 Power-Tronics, Inc.
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Connection Diagram
(See page 7 if the generator will be paralleled using this product)
The SEM100A is a Half-Wave rectified static exciter, which allows a maximum of
105VDC at 90 ADC continuous with an input voltage of 240VAC.
This product is typically used on slip-ring generators with full load field voltages of
63VDC or less and full load exciter field amperages between 30 and 90ADC.
Note that the maximum input voltage to the SEM100A Static Exciter Module is
240VAC! DO NOT input 277VAC into the SEM100A! Severe damage to the unit will
result! For use on 480V systems, either connect the SEM100A to the winding center
taps T7 and T8 or use a 480-240V step-down transformer.
Connecting the input of the SEM100A 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!
XR or UVR Series Voltage Regulator, or
UVR, XR, or PC series Phase Controller
NOTE:
If the generator is
to be operated
below 50/60 Hz, a
disconnect or
switch should be
installed in series
with red wire of
the SEM100A.
NEVER install a
switch or
breaker on the
DC or Exciter
side of the Static
Exciter! Only
install a switch
or disconnect in
the red wire, or
on the AC side
of the SEM100A!
SEM100A
AC1 AC2/F-F+
Gray
White
Red

© 2012 Power-Tronics, Inc.
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Parallel Connection Diagram
To use the SEM100A Static Exciter Module 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 SEM100A.
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 7Ωbefore 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 25VA or larger capacity!
XR or UVR Series
Voltage Regulator, or
UVR, XR, or PC series
Phase Controller
SEM100A
AC1 AC2/F-F+
Gray
White
Red
Fuse Inputs
at no more
than
100ADC!
XR or UVR Series
Voltage Regulator,
or
UVR, XR, or PC
series Phase
Controller
NOTE:
It is not necessary to jumper
terminals 7 and 8 if not using the
Remote Voltage Adjustment!
NOTE:
If the generator is to be
operated below 50/60 Hz, a
disconnect or switch should
be installed in series with
red wire of the SEM100A.
NEVER install a switch or
breaker on the DC or
Exciter side of the Static
Exciter! Only install a
switch or disconnect in
the red wire, or on the AC
side of the SEM100A!

© 2012 Power-Tronics, Inc.
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Initial Setup and Commissioning
1. Install the regulator and SEM100A module and wire up to the connection diagram.
2. If installing the SEM100A on a brush-type generator, verify that the brushes and brush
riggings are isolated, ungrounded, and connected ONLY to the SEM100A.
3. Turn the internal voltage control on the voltage regulator 15 or more turns counter
clockwise (left) or until you hear the screw 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 6Ωand 10Ω.
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 on the voltage regulator 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!
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
Frequency Selection
(XR500C and XR500D)
Remove jumper for 50Hz
operation. This product’s
default setting is 60Hz.
(Pull up to remove)
System
indicator light

© 2012 Power-Tronics, Inc.
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Optional Power-Tronics Add-On Modules
Power-Tronics offers a wide array of optional add-on modules for the SEM100A
Static Exciter Module from automatic flashing modules to digital interface cards.
For more information on any of the modules below, visit our online catalog at:
www.power-tronics.com
AFM500X
Automatic Flash Module
Adds Automatic Flash or
Battery Flash to installations
with low residual or requiring
guaranteed buildup!
UIC200
Optical Interface Module
Allows the XR500D to be
controlled externally by virtually
any digital load-sharing controller,
VAR controller, genset controller,
or digital governor controller!
MP12/MP24
Motorized Potentiometer
Allows the XR500D to be
externally controlled by older
automated controllers using
pulsed signals or dry contacts
for control!
HVD1
High Voltage Disconnect
Module
Saves your generator and connected
equipment from runaway voltage
conditions! Disconnects power to the
voltage regulator instantly in the
event of high voltage!

© 2012 Power-Tronics, Inc.
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Application Troubleshooting
Problem: Possible Cause
No Voltage 1 3 5 7 9 11 13 15 20
Pulsating Voltage 4 5 6 12 16 20
Flickering Voltage 4 6 7 14 20
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 20
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. 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 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.