Mechanics Hoists
PAGE: 22
Model MH
MH-0214
2721 NE 4th Ave Pompano FL 33064| (954) 367-6116
Visit WWW.ACIHOIST.COM for the most current information
7.0 TROUBLESHOOTING
Table 7.1
Symptom
Cause
Remedy
Hoist 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.
Hoist overload
Reduce load to within rated capacity of hoist.
Improper, loose or broken
wire in the hoist electrical
system
Shut off power supply, check wiring connections on
hoist control panel and inside push button pendant.
Brush wear
Inspect both motor brushes per Motor Brush Dimensions
Table (page 6). and replace, if necessary.
Fuses burned out
Replace fuses.
Motor burned out
Replace motor frame/stator, shaft/rotor and any other
damaged parts.
Hoist lifts but will
not lower
Faulty switch in pendant
Check electrical continuity. Check electrical connections.
Replace or repair as needed.
Broken conductor in
pendant cord
Check the continuity for each conductor in the cable. If
one is broken, replace the entire cable.
Hoist lowers but
will not lift
Hoist overload
Reduce load to within rated capacity of hoist.
Worn friction clutch
Repair by a qualified person trained in the repair of
hoists and proper friction clutch adjustment procedures.
Replace as needed.
Broken conductor in
pendant cord
Check the continuity for each conductor in the cable. If
one is broken, replace the entire cable.
Faulty switch in pendant
Check electrical continuity. Check electrical connections.
Replace or repair as needed.
Low voltage in hoist’s
power supply
Determine cause of low voltage and bring to within plus
or minus 5% of the voltage specified on the motor
nameplate. The voltage should be measured at the hoist
contactor.
Hoist will not lift
rated load or does
not have the
proper lifting
speed
Hoist overload
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 5% of the 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
Motor demagnetized
Motor demagnetizing is generally caused from using the
hoist beyond its duty rating. Replace stator assembly
and reduce usage to comply with the duty rating stated.
Improper gear oil
Replace oil with the correct gear oil.
Hoist operates
intermittently
Loose connection in circuit
Check all wires and terminals for bad connections.
Replace as needed.
Collectors making poor
contact
Check movement of spring loaded arm, weak spring,
connections and shoe. Replace as needed.
Broken conductor in
pendant cord
Check for intermittent continuity in each conductor in the
pendant cord. Replace the entire pendant cord if
continuity is not constant.
