MC3 ChipMaster, Operation & Maintenance Manual, Page: 49 / 63

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3. Fault
Isolation
If the motor has failed or does not meet the requirements of any of the tests described above, use the fault isolation
procedures provided in Table 4, Motor Fault Isolation. The table is based on the assumption that the motor has been
operating correctly, and that a problem has occurred. If a newly installed motor does not operate correctly, the
problem is an installation problem.
Fault Check Corrective Action
Check the circuit breaker. The breaker has tripped. Reset the breaker.
If the breaker trips immediately, the motor
windings have shorted. Replace the motor.
Check the motor and the gearbox
separately to determine which has failed. Replace the motor or the gearbox, as applicable.
If the breaker has not tripped, check the
power circuitry to the motor. If the power circuitry has opened, repair the
power circuitry.
Motor doesn’t
operate
Check for an open in the motor windings. If the motor windings have an open circuit,
replace the motor.
Motor is noisy Separate the motor from its gearbox and
check the shaft bearings by hand
according to the TEST instructions. If the bearings feel rough, replace the bearings
according to the instructions in REPAIR.
Check the motor exterior for an excessive
accumulation of oil and dirt that can
inhibit cooling. If the motor exterior is excessively dirty, clean
the motor surface using clean, lint-free cloths.
If the motor has a finned casing, use a vacuum
cleaner and a stiff-bristled nylon brush to remove
dirt and debris from between the fins.
If the motor has a vented enclosure,
check the vent openings to make sure
they are clear. If necessary, clean the vent openings.
Visually check for heat-discolored paint,
which is evidence of a motor overheat. If the motor casing shows heat discoloration, the
motor is failing. Replace the motor.
Motor thermal
protection trips
Check the system load. If the load applied to the system is above rated
load, it should be reduced, if possible, to avoid
affecting motor life.
Check for increased load. If the load has increased beyond rated load,
correct the overload condition to prevent damage
to the motor.
Check for supply voltage drop. Supply voltage must be within 10 percent of
nominal voltage. If the supply voltage is less
than 90 percent of rated voltage, correct the
supply voltage to avoid damage to the motor.
Motor slows
during operation
Check the gearbox and the motor
bearings for wear and drag that increases
as the system temperature rises. If the gearbox drag increases during operation,
repair the gearbox.
If the motor bearing drag increases as the motor
operates, replace the bearings according to
REPAIR.
Table 4. Motor Fault Isolation