If the controlle r initiates a safety shutdown, it displays the fault on the L ID with a primar y and
a secondary message, and energizes an alarm rela y in the starter and blinks the alarm light on
the control center. The alarm is stored in memory an d can be viewed in the PIC A lar m Hi story
table along wit h a message for troublesho oting.
To give a bett er warning as to the opera ting condition of the machin e, the operato r also can
define alert limits on v ar io us monitored inputs . Safety contact and ale r t li mits are defined in
Table 3. Alarm and al er t messages are listed in th e Troubleshooting Guide section.
Shunt Trip
The optional shunt tri p fu nction of the PIC is a safet y trip. The shunt trip is wir ed f rom an
output on the SMM to the motor circuit breaker. If the PIC tries to shut down the compressor
through normal shu tdown procedure but is unsuccessf ul for 30 seconds , the shunt tri p output is
energized and causes t he c ir c u it breaker to trip off . I f gro und fault protection has been applied
to the starter, the grou nd f ault trip will also ene rgize the shunt trip to trip the circuit breaker.
CAUTION CAUTION
!
If compressor motor ov erl oad or ground fault occ urs, check the motor for
grounded or open phases b efore attempting a re st ar t.