Harrington Hoists and Cranes MR Trolley - (MR2) - Manual (Page 47)

7.0 Troubleshooting

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.”
To avoid a shock hazard, DO NOT perform ANY mechanical or electrical maintenance on the dual speed (or VFD
control) trolley or hoist within 5 minutes of de-energizing (disconnecting) the trolley or hoist. This time allows the
internal VFD capacitor to safely discharge.
Only trained and competent personnel should inspect and repair this equipment.

Do Not perform “withstand voltage” test or “insulation resistance” measurement (megger) with the VFD connnected.
Do Not remove power to the hoist or trolley during operation.
Do Not connect power to the output of the VFD.
When handling VFD provide ESD protection.
Table 7-1 Troubleshooting Guide
Symptom Cause Remedy
Trolley will not operate
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
thermal overload
protector has tripped See Troubleshooting 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.
Faulty VFD
(dual speed only) Check fault codes (Reference Section 3.5). Reset VFD by
pressing the Emergency Stop button on the pendant. Replace as
needed.
Emergency Stop
Depressed on Push
Button Pendant
Control
“Hbb” will appear on the dual speed unit’s VFD display when the
Emergency Stop Button is depressed. Turn the Emergency Stop
Button clockwise to unlock the controls and allow hoist operation.
Motor burned out Replace motor frame/stator, shaft/rotor, and any other damaged
parts.
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