User manual
Publication 1394-5.0 — May 2000
Troubleshooting 9-15
Condition: Possible cause: Possible resolution:
No Rotation
The motor connections are loose or open.
Check motor wiring and 
connections.
Foreign matter is lodged in the motor.
Remove foreign matter.
The motor load is excessive.
Size the servo system.
The bearings are worn.
Return the motor for repair.
The motor brake is engaged (if supplied).
• Check brake wiring and 
function.
• Return the motor for repair.
The motor is not connect to the load.
Check coupling.
Overheating
The duty cycle is excessive.
Change the command profile to 
reduce accel/decel or increase 
time.
The rotor is partially demagnetized causing excessive 
motor current.
Return the motor for repair.
Abnormal Noise
[Prop Gain Kp, Intg Gain Ki, Feed Fwd Gain] parameters 
(368, 372, 376 (Analog Servo only)) are set too high.
Run auto tune again.
Loose parts are present in the motor.
• Remove the loose parts.
• Return motor for repair.
• Replace motor.
Through bolts are loose.
Tighten bolts.
The bearings are worn.
Return motor for repair.
Erratic Operation - Motor
locks into position, runs
without control or with
reduced torque
Phases A and B, A and C or B and C reversed.
Check and correct motor power 
wiring.
Sine, Cosine or Rotor leads are reversed in the feedback 
cable connector.
Check and correct motor feedback 
wiring.
Sine, Cosine, Rotor lead sets of resolver feedback are 
reversed.
Check and correct motor feedback 
wiring.










