Troubleshooting - Jet JEH Series Operation Manual

TROUBLESHOOTING THE JEH HOIST
Trouble
Motor will not run.
Hoist lifts very slowly.
Hoist lifts but will not lower.
Hoist lowers but will not lift.
Load continues drifting
down excessively when
hoist is stopped.
Motor overheats.
Poor engagement of chain
with sprocket/sheave.
Brake chatters.
Limit switch failure.
12
Probable Cause
No incoming power, or
low voltage.
Rectifier damaged so that the
brake won't release.
Motor damaged.
Overloaded.
Low voltage.
Broken conductor in pendant cord.
Up/down switch malfunctioning.
Overloaded.
Up/down switch malfunctioning.
Brake malfunction.
Hoist overloaded.
Grease or oil on the lining.
Brake disc is worn.
Brake springs are damaged.
Excessive load or
too frequent use.
Brake drags.
Load chain is seriously worn.
Sprocket wheel, sheave or chain
guide is seriously worn.
Check for greater than allowable
air gap.
If the brake still chatters after
being replaced check the rectifier
for proper operation.
Bad connection of limit
switch leads.
Limit switch damaged.
Remedy
Check circuit breakers, switches and
connections in power supply lines. If low
voltage, have a certified electrician test
incoming power.
Have rectifier replaced by qualified
service personnel.
Have motor replaced by a qualified
service technician.
Reduce load.
Determine cause of low voltage and bring up
to within +/- 10% of the voltage listed on the
hoist nameplate.
Test continuity of each conductor.
Replace cable if needed.
Repair or replace switch.
Reduce load to within hoist capacity.
Repair or replace switch.
Have brake inspected by qualified personnel.
Replace if needed.
Reduce load to within rated capacity.
Have a qualified technician disassemble
the brake and clean the lining.
Replace brake assembly.
Replace brake springs (qualified personnel).
Operate within rated load and according to
duty cycle rating.
Adjust brake clearance (qualified personnel).
Replace load chain.
Replace parts as needed.
Replace brake assembly.
Have rectifier replaced by qualified
service personnel.
Inspect the contacts of the leads and
limit switches.
Replace limit switch.