Product Manual

4. Troubleshooting3-2016
39A046S594 (Issue 12) Copyright © 2016 Cummins Inc.
TABLE 7. TROUBLESHOOTING THE TRANSFER SWITCH (PROBLEM #2)
Problem Possible Cause Corrective Action
The transfer switch
failed to transfer to
the utility
1. The Utility source may not be present.
2. The K2 relay is faulty — used to detect if
utility voltage is present.
3. The K1 relay coil may not have received
a ground signal
4. K1 relay may malfunction.
5. There may be a defective wire.
6. The switch mechanism solenoid may be
burnt out.
7. There may be loose or broken parts
within the switch mechanism.
8. TB4 jumper is incorrectly installed (on
Air-Cooled Generator Sets only).
1. Check:
a. To see that the Utility service
disconnect (circuit breaker) is in
the ON position.
b. For a ground (B-) signal on TB4-1.
2. Replace the relay.
3. Check for a relay coil signal (B-) on TB4-
3 and 12VDC on TB4-7.
4. Verify the relay coils are energizing.
a. If the coils are 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.
b. If the coils are not energizing,
• Check to see if the K1 relay
is faulty.
• If faulty, replace the K1 relay.
5. Check, inspect, or replace the defective
wire.
6. 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. 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.
8. Refer to interconnect diagram in
Appendix B and check for the transfer
command signal at TB4. Generator Set
Models C13N6H, C17N6H and C20N6H
require a jumper between TB4-3 and
TB4-4.