7
TROUBLESHOOTING
Covers D12 and D24 Models
General:
The chart below will be helpful for isolating malfunctions in the control system, countering difficulties with
system start-up, and in troubleshooting for worn or broken mechanical or electrical components in units which have
been operating for sometime. For correct diagnosis it is important to do all tests before disassembling the actuator.
If the actuator is being used in conjunction with an MCS controller, see Troubleshooting Guide in controller manual
for additional checkpoints.
Symptom: Actuator will not extend/retract
Checkpoint
Probable Cause
Possible Solution
No voltage or amp draw
Actuator not receiving power
-Check power supply
Proper voltage, no amp draw
Dead motor
-Replace motor
Thermal overload cut-out
-Let cool, check duty cycle
(when overheated)
Proper voltage, amp draw
Actuator overloaded
-Check rated load
present, clutch slips
Clutch worn too low
-Replace clutch
(Excessive ratcheting)
Symptom: Actuator stops in mid-stroke
Checkpoint
Probable Cause
Possible Solution
Clutch slips
Actuator overloaded
-Check rated load
Clutch doesn’t slip, no amps
Blown fuse (customer provided)
-Replace fuse
Thermal cut-out
-Let cool, check duty cycle
Clutch doesn’t slip, amps
Motor stalled
-Check voltage too low
present
If the above checks do not reveal the source of the difficulty, remove actuator from the mechanism to run by itself.
Watch and listen for any changes in behavior.
Summary of Contents for THOMSON D12-05B5
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