TS 910 TRANSFER SWITCH
PM140 REV 0 12/02/09
35
Thomson Technology
18.8.
TSC 9 OPERATING MODE DESCRIPTIONS
18.8.1.
TRANSFER SWITCH FAIL ALARM LOGIC
The TSC 9 controller contains logic to detect abnormal operation during
various failure modes. Detailed operating logic is as follows:
18.8.1.1.
Utility Limit Switch Failure:
Should the utility power contactor limit switch fail to close when the contactor
is in the utility position, an alarm condition will be activated after a 10 second
delay. This alarm condition will cause the following events to occur:
•
Force Transfer
: a forced transfer to the generator supply will be
activated. A generator start signal will be initiated to start the
generator and load will transfer to the generator supply if within
normal limits. Re-transfer back to the utility supply will not occur
until the Transfer Fail alarm condition is reset.
•
‘
On Utility’ LED Flashes
: the “On Utility’ LED will begin flashing
to indicate that the utility limit switch is not operating correctly.
The LED will flash until the alarm condition is reset.
•
‘
Alarm’ LED Activated
: the ‘alarm’ LED’ will be activated. The
LED will not go out until the alarm condition is reset.
•
Alarm Output Signal
Activated
: the output signal on customer
terminals #5 & #6 will be activated. The alarm output signal will
be terminated once the alarm condition is reset.
18.8.1.2.
Generator Limit Switch Failure:
Should the generator power contactor limit switch fail to close when the
contactor is in the generator position, an alarm condition will be activated after
a 10 second delay. This alarm condition will cause the following events to
occur:
•
Force Transfer
: a forced transfer to the utility supply will be
activated. The load will automatically be transferred to the utility
supply if within normal limits. Re-transfer back to the generator
supply will not occur until the Transfer Fail alarm condition is
