RAM DBS II
Refrigeration Solid State Starter
23
TRIP CONDITION
1.
Jam
2.
Short Circuit
3.
Thermal Overload
4.
Shorted SCR (circuit breaker
trips about 5 seconds after
energizing controller).
SOLUTION
Confirm Jam trip and trip delay
setpoints.
Resolve mechanical problems of
driven equipment.
Verify DBS controller settings;
prevent excessive loading during
start.
Remove cause of short or ground.
Reconfigure connections.
Allow motor to cool then re-start.
Compare reading from clamp-on
ammeter with readout on display unit
to confirm accurate sensing by DBS.
Motor should be started less
frequently.
Confirm setpoints:
• FLA (SW1)
• Locked rotor current
• Stall time
• Service factor
• Chassis Size (SW6)
Check SCRs per test procedure.
(See Appendix) Call RAM if
defective. Do not replace in field.
If SCRs are OK, replace circuit
board.
Repair or replace contactor.
Repair gate plug connection or
connector.
Reconfigure connections.
Connect motor to starter.
POSSIBLE CAUSE
Current exceeded Jam Trip level
set point longer than time delay
set point while in RUN state.
Driven equipment may be bound
or set up improperly.
Current exceeded 800% of FLA
set point while motor was
starting.
Short in starter or motor junction
box: phase-to-phase, phase-to-
ground.
Motor incorrectly connected.
Calculated thermal capacity of
motor exceeded 100% of limit.
Excessive motor current
detected.
Motor is "short-cycling".
DBS settings not within design
parameters.
Defective SCR; Current
measured when motor is not
running.
Defective circuit board.
Defective bypass contactor;
welded contacts.
Gate plug P3, P5, or P7 may be
loose.
Motor connections incorrect.
Motor not connected to starter.
TABLE 10
(continued)
7.2 Trip Conditions
(continued)
7.0 Troubleshooting
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