Harrington Hoists and Cranes SMR Trolley - Manual (Page 34)

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7.0 Troubleshooting
WARNING
HAZARDOUS VOLTAGES ARE PRESENT IN THE TROLLEY AND IN CONNECTIONS
BETWEEN COMPONENTS.
Before performing ANY maintenance on the equipment, de-energize the supply of electricity to the
equipment, and lock and tag the supply device in the de-energized position. Refer to ANSI Z244.1,
“Personnel Protection – Lockout/Tagout of Energy Sources.”
Only Trained and competent personnel should inspect and repair this equipment.
Table 7-1 Troubleshooting Guide
Symptom Cause Remedy
Loss of power Check circuit breakers, switches, fuses and connections on power
lines/cable.
Wrong voltage or
frequency Check voltage and frequency of power supply against the rating on the
nameplate of the motor.
Motor overheated and
optional thermal overload
protector has tripped See Trouble Shooting Problem "Motor or brake overheating".
Improper, loose, or
broken wire in trolley
electrical system Shut off power supply, check wiring connections in the trolley switch box,
on hoist control panel and inside push-button pendant.
Faulty magnetic contactor Check coil for open or short circuit. Check all connections in the control
circuit. Check for open contactors. Replace as needed.
Motor burned out Replace motor frame/stator, shaft/rotor, and any other damaged parts.
Faulty Start Switch
(model MP1A only) Disconnect Start Switch from motor. The resistance between the Start
Switch terminals 2 and 3 should be greater than 500K ohms. If not,
contact factory for detailed Start Switch troubleshooting.
Trolley will not operate
Faulty Start or Run
Capacitor Check capacitor(s) for open or short circuit. Check connection. Replace
as needed.
Trolley drifts excessively
when stopping Motor brake not holding Clean and inspect brake lining. Replace if necessary
Excessive duty cycle Reduce frequency of trolley movement.
Motor or brake
overheating Extreme external heating Above an ambient temperature of 140°F, the frequency of trolley
operation must be reduced to avoid overheating of the motor. Special
provisions should be made to ventilate the trolley or otherwise shield it
from the heat.
Collectors making poor
contact Check movement of spring loaded arm, weak spring, connections, and
shoe. Replace as needed.
Contactor contacts arcing Check for burned contacts. Replace as needed.
Loose connection in
circuit Check all wires and terminals for bad connections. Replace as needed.
Trolley operates
intermittently
Broken conductor in
Pendant Cord Check for intermittent continuity in each conductor the Pendant Cord.
Replace entire Pendant Cord if continuity is not constant.