Harrington Hoists and Cranes SNER Hoist - Manual (Page 35)

35
Table 7-1 Troubleshooting Guide
Symptom Cause Remedy
Hoist will not operate
(continued)
Faulty Start Switch
Disconnect Start Switch from motor. The resistance between the
Start Switch terminals 2 and 3 should be greater than 500K ohms.
If not, consult factory.
Faulty Start
Capacitor(s) Check capacitor(s) for open or short circuit. Check connections.
Replace as needed.
Hoist lifts but will not
lower
Down circuit open
Check circuit for loose connections. Check down side of limit
switch for malfunction.
Broken conductor in
pendant cord Check the continuity for each conductor in the cable. If one is
broken, replace entire cable.
Faulty magnetic
contactors 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.
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
If abnormal operation or slippage occurs do NOT attempt to
disassemble or adjust the Friction Clutch. Replace the worn or
malfunctioning Friction Clutch as an assembly with a new, factory
adjusted part.
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.
Brake drags Check motor brake adjustment for proper clearance.
Faulty friction clutch
If abnormal operation or slippage occurs do NOT attempt to
disassemble or adjust the Friction Clutch. Replace the worn or
malfunctioning Friction Clutch as an assembly with a new, factory
adjusted part.
Load drifts excessively
when hoist is stopped Motor brake not
holding Clean and inspect brake lining. Check brake adjustment for
proper clearance.