TP-6745 7/1054 Section 3 Controller Test and Replacement
GM71061
Transfer, Normal to Off:
Utility source is lost.
Controller relay K2 closes,
energizing the UBO motor
operator to open the utility
breaker.
Note: Controller relays K1 and K2 and PTIB
relays K1’ and K2’ are energized for only
250 milliseconds to initiate transfer.
Transfer, Off to
Emergency:
PTIB relay K2’ closes,
energizing the GBC
motor operator to close
the generator breaker.
Figure 3-10 ICCB Transfer from Normal to Emergency