Product Manual

4. Troubleshooting 7-2019
24 A052S254 (Issue 3)Copyright © 2019 Cummins Inc.
TABLE 8. TROUBLESHOOTING THE TRANSFER SWITCH (PROBLEM #2)
Problem Possible Causes Corrective Actions
The transfer switch
failed to transfer to
the utility.
1. The utility source may not be present.
1. Check to see that the Utility service
disconnect (circuit breaker) is in the ON
position.
2. Make sure that the feeder breaker to the
transfer switch is on.
3. Check for a ground (B-) signal on TB4-1.
2. The K2 relay, which is used to detect if
utility voltage is present, is faulty.
Replace the relay.
3. The K1 relay coil may still be receiving a
signal due to a shorted wire or TB4 jumper is
incorrectly installed.
Refer to the interconnect diagram at the back
of this manual and verify the generator set
transfer command is inactive. Only generator
set models C13N6H, C17N6H, C20N6H
should have a jumper between TB4-3 and
TB1-4.
4. The K1 relay may have malfunctioned. Verify that the K1 relay coil is de-energizing:
1. If the coil is de-energizing:
• Check the voltage between the
relays and the transfer switch (A1
and A2). It should be 240 VAC.
• Check to see if the transfer switch
is faulty.
2. If the coil is not de-energizing:
• Check to see if the K1 relay is
faulty.
• If faulty, replace the K1 relay.
5. There may be a defective wire. Check, inspect, or replace the defective wire.
6. The switch mechanism solenoid may have
failed.
Be sure that both voltage sources are turned
off before operating the switch manually.
Manually operate the switch by using the
operator handle to manually transfer the
switch. If the switch manually transfers, the
solenoids are burnt out; replace the switch
mechanism.
7. There may be loose or broken parts within
the switch mechanism.
Be sure that both voltage sources are turned
off before operating the switch manually.
Manually operate the switch by using the
operator handle to manually transfer the
switch. If the switch does not manually
transfer, replace the switch mechanism.