4-6 Controller Troubleshooting
TP-5672 11/95
Incorrect Normal Source Voltage And Frequency Values
See Appendix B, Figure B-9 for location of TB-AC1 and
other power supply board components referred to in this
section.
1. If the system is single-phase, use a voltmeter to
measure the normal source voltage by connecting
one test lead to TB-AC1-NA and the other test lead
to TB-AC1-NC. Note the voltmeter reading.
2. If the system is three-phase, use a voltmeter to
measure the normal source voltage by connecting
one test lead to TB-AC1-NA and the other test lead
to TB-AC1-NB. Note the voltmeter reading.
Connect one test lead to TB-AC1-NB and the other
test lead to TB-AC1-NC. Note the voltmeter
reading.
3. If the voltmeter did not display the normal source
voltage in step 1 or step 2, check the normal source
and the contactor-to-assembly harness, P1.
4. If the voltage reading(s) in step 1 or step 2 did not
match the value(s) displayed in Index 1, check the
power supply board by performing the following four
steps.
NOTE
When taking a voltage or resistance measurement
at a ribbon cable pin, do not disconnect the ribbon
cable from the board. Use a needle point probe to
take the readings from the holes on the top side of
the ribbon cable connector.
a. Check the Test LED on the power supply board.
If the Test LED is not on, install a jumper between
TB-DC1-24 and TB-DC1-34. If the Test LED
comes on when the jumper is installed, check the
Automatic/Test pushbutton and the connected
accessories.
b. Using a voltmeter, connect one test lead to
P2-15 and the other test lead to TB-DC1-34. See
Appendix B, Figure B-9 for location of P2 ribbon
cable connector. The voltmeter should read
approximately 1/25 of the line voltage. See
Appendix B, Figure B-5 for values. Turn the
generator off. See Appendix B, Figure B-9 for
location of P2 ribbon cable pins.
c. Connect one test lead to P2-16 and the other to
TB-DC1-34. The voltmeter should read
approximately 1/25 of the line voltage. See
Appendix B, Figure B-5.
d. If the system is three-phase, connect one test
lead to P2-17 and the other to TB-DC1-34. The
voltmeter should read approximately 1/25 of the
line voltage. See Appendix B, Figure B-5.
e. If the system is three-phase, connect one test
lead to P2-18 and the other to TB-DC1-34. The
voltmeter should read approximately 1/25 of the
line voltage. See Appendix B, Figure B-5.
f. Remove power from the logic board. Disconnect
the P2 ribbon cable connector. Recheck the P2
points on the power supply board in steps 4a, 4b,
4c, and 4d. If the voltage readings are now
correct, either an accessory or the logic board
main logic board is bad.
5. If any of the voltage readings in step four were
incorrect, replace the power supply board. If all of
the voltage readings in step four were correct,
calibrate the normal source voltage.
Calibrate Logic Board Normal
Three-Phase Source Voltage
1. Press the Automatic/Test pushbutton to start the
generator and to transfer the load to the generator.
2. Disconnect the incoming normal power to the
transfer switch by removing the line fuses, the
in-line disconnect plug, or the incoming circuit
breaker.
3. Verify that the normal source voltage is zero. Using
a voltmeter connect one test lead to TB-AC1-NA
and one test lead to TB-AC1-NC. The voltmeter
should read 0 volts AC. Connect one voltmeter test
lead to TB-AC1-NA and the other test lead to
TB-AC1-NB. The voltmeter should read 0 volts AC.
Connect one voltmeter test lead to TB-AC1-NB and
the other test lead to TB-AC1-NC. The voltmeter
should read 0 volts AC.
4. If the normal source is three-phase, it can be
sensed as either single-phase or three-phase
depending on what the application requires. In
Menu Index 6 choose the appropriate sensing
method: single-phase sensing or three-phase
sensing.
NOTE
When calibrating either the normal source or
emergency source, never auto-zero the source
unless it is zero volts. If source voltage is present
and the YES key is pressed and entered at the
AUTO-ZERO message, the logic board will always
read the system voltage as zero volts.
5. Using the menu in Index 12, arrow down to
N-AUTO-ZERO? and press the YES key and the
ENTER key.
6. Observe the ENTRY ACCEPTED message on the
LCD.
