Harrington Hoists and Cranes MR Trolley - (MR2) - Manual (Page 48)

Table 7-1 Troubleshooting Guide
Symptom Cause Remedy
Trolley drifts
excessively when
stopping
Motor brake not
holding Clean and inspect brake lining. Replace if necessary
VFD Deceleration
parameter adjusted
incorrectly
(Dual Speed only)
Readjust VFD Deceleration parameter (Reference Section
3.5.11).
Motor or brake
overheating
Excessive duty cycle Reduce frequency of trolley movement.
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.
Trolley operates
intermittently
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.
Faulty VFD
(dual speed only)
Check fault codes (Reference Section 3.5). Replace as needed.
Loose connection in
circuit Check all wires and terminals for bad connections. Replace as
needed.
Broken conductor in
Pendant Cord Check for intermittent continuity in each conductor the Pendant
Cord. Replace entire Pendant Cord if continuity is not constant.
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