Mitsubishi Electric MELSERVO-J3W Series Instruction Manual page 154

8. TROUBLESHOOTING
Alarm No.31
Alarm description
Display Name
31.1 Abnormal motor
speed
Name: Overspeed
Servo motor speed exceeds the instantaneous permissible speed.
Cause
(1) The command from the
controller is excessive.
(2) Overshoot of speed
occurs as the motor starts
in the maximum torque.
(3) Servo system is instable
and causing oscillation.
(4) Overshoot of velocity
waveform occurs.
(5) Encoder is faulty.
Stop method: Corresponding axis stops
Checkpoint
The command from the Permissible rotation
controller is over the speed or larger.
permissible speed range.
Within the permissible
rotation speed.
Acceleration torque is Operating at
clamped to the maximum maximum torque.
torque.
Operating below
maximum torque.
Check for oscillation in Oscillation is
motor. occurring.
Oscillation is not
occurring.
Acceleration time Overshoot occurs.
constant is too short
causing overshoot.
Overshoot does not
occur.
Check if alarm occurs Alarm occurs.
when the actual speed is
lower than instantaneous
permissible speed.
8 - 15
Finding Action
Review the operation
pattern.
Check (2).
Set acceleration time
longer or reduce the
load.
Check (3).
Execute auto tuning to
adjust the servo
system, or reduce the
load.
Set acceleration time
constant longer.
Check (4).
Set acceleration time
constant longer.
Check (5).
Replace the servo
motor.