Thermo King RD-MT - Electric Standby Diagnosis; Unit switch On-indicator lights do not come on; Unit switch On-indicator lights come on but electric motor does not run; Electric motor hums but does not run

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Electric Standby Diagnosis
Condition Possible Cause Remedy
Unit switch On—indicator lights
do not come on
Battery discharged Charge or replace battery
Circuit breaker open Check for short circuit in unit wiring
Control circuit blown Replace control circuit
Reset switch tripped Push reset switch button in
Unit switch On—indicator lights
come on but electric motor does
not run
Diesel/Electric switch on Diesel Move switch to Electric position
No standby power Provide power to unit; check power
at:
1. Power source
2. Power plug
3. Motor contactor hot side
4. Motor contactor load side
(contactor closed)
5. Overload relay
6. Motor terminals
Defective motor contactor Repair or replace motor contactor
Defective low oil pressure switch Replace low oil pressure switch
Overload relay tripping Check for shorted motor windings or
wires
Defective motor Replace motor
Batteries discharged Charge or replace batteries
Electric motor hums but does not
run
Locked rotor (overload relay will
open)
Repair or replace motor
Locked compressor Repair compressor
Defective clutch on engine (locked
up)
Repair or replace clutch
Low line voltage or no voltage on
one leg
Bring voltage up to within 10% of
motor rating
Single phase power to 3-phase
motor or visa versa
Check power
Worn motor bearings Repair