Harrington Hoists and Cranes ED-DA Hoist - (ED3) - Manual (Page 36)

36
Table 7-1 Troubleshooting Guide
Symptom Cause Remedy
Hoist lowers but will
not lift
Hoist overloaded Reduce load to within rated capacity of hoist.
Low voltage in hoist's
power supply
Determine cause of low voltage and bring to within plus or minus
10% of the voltage specified on the motor nameplate. The
voltage should be measure at the hoist contactor.
Up circuit open
Check circuit for loose connections. Check up side of limit switch
for malfunction.
Broken conductor in
pendant cord Check the continuity of each conductor in the cable. If one is
broken, replace entire cable.
Faulty magnetic
contactor Check coils for open or short circuit. Check all connections on
motor circuit. Check for burned contacts. Replace as needed.
Faulty switch in
pendant Check electrical continuity. Check electrical connections.
Replace or repair as needed.
Faulty friction clutch
Repair by a qualified person trained in the repair of hoists and
proper friction clutch adjustment procedures. Replace as needed.
Hoist will not lift rated
load or does not have
the proper lifting speed
Hoist overloaded Reduce load to within rated capacity.
Low voltage in hoist's
power supply
Determine cause of low voltage and bring to within plus or minus
10% of voltage specified on the motor nameplate. The voltage
should be measured at the hoist contactor.
Faulty friction clutch
If abnormal operation or slippage occurs do NOT attempt to
disassemble or adjust the Mechanical Load Brake with Friction
Clutch. Replace the worn or malfunctioning Mechanical Load
Brake with Friction Clutch as an assembly with a new, factory
adjusted part.
Load drifts excessively
when hoist is stopped
Mechanical Load
brake not holding
Replace as needed.
Improper gear oil Replace oil with the correct Harrington ED gear oil.
Motor demagnetized
Motor demagnetizing is generally caused from using the hoist
beyond it's duty rating. Replace stator assembly and reduce
usage to comply with the duty rating stated in Table 2-1.
Dynamic brake resistor
burned out
Check resistance and replace if necessary.