KNIGHT D-SERIES SERVO HOIST OPERATION MANUAL
SECTION 7
TROUBLESHOOTING
130
D. Troubleshooting Chart
The Servo Hoist operation may be affected by various factors. If your hoist is not performing as well as
expected, follow the table below to diagnose the problem. If unable to resolve the issue, contact the
Knight Global Service Department at 248-375-7962 or via e-mail at
.
Problem
Cause
Solution
Hoist does not lift or lower
Power loss
Check switches, and connections of all power
lines.
Check Run-Stop button, reset if necessary.
Incorrect voltage
Check supply voltage and frequency of power
supply to ensure it is correct for the
Servo Hoist.
Electrical fault
Secure power to the hoist; check all wiring
and connections on the Servo Hoist.
Hoist capacity exceeded
Reduce the weight of the load to within the
rated or programmed capacity of the
Servo Hoist.
Servo Hoist lifts but does not lower
"Lower Limit" set incorrectly
Check parameters:
fPRM:1 ‘Overall Forward/Lower Limit’,
fPRM:3 ‘Lift Mode Forward/Lower Limit’,
fPRM:5 ‘Float Mode Forward/Lower Limit’.
Damaged pendent cord
Check each conductor in the pendent cable
for continuity.
Replace damaged cable as required.
Servo Hoist lowers but will not lift
"Top Limit" set incorrectly
Check parameters:
fPRM:0 ‘Overall Reverse/Upper Limit’,
fPRM:2 ‘Lift Mode Reverse/Upper Limit’,
fPRM:4 ‘Float Mode Reverse/Upper Limit’.
Damaged pendent cord
Check each conductor in the pendent cable
for continuity.
Replace damaged cable as required.
Hoist capacity exceeded
Reduce the weight of the load to within the
rated capacity of the Servo Hoist.
Low voltage in power supply
Determine the cause of low voltage and
restore voltage back to /-10% of
required voltage supply.
Servo Hoist does not lift at proper
speed
Hoist capacity exceeded
Reduce the weight of the load to within the
rated or programmed capacity of the
Servo Hoist.
Low voltage in power supply
Determine the cause of low voltage and
restore voltage back to /-10% of
required voltage supply.
Servo Hoist operates intermittently
Open / Short circuit
Check circuit for loose connections or broken
conductors. Repair or replace as necessary.
Damaged pendent cord
Check each conductor in the pendent cable
for continuity.
Replace damaged cable as required.
Damaged handle
Check each conductor in the pendent cable
for continuity.
Replace damaged conductors as required.
Check connections and replace if necessary.
Table 7-1