Mitsubishi Electric MELSERVO-JN Series, Instruction Manual

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8. TROUBLESHOOTING
Alarm No.: A.31 Name: Overspeed
Description Servo motor speed has exceeded the instantaneous permissible speed.
Detailed
display
Detailed
Name
Cause Checking method Result Action
31.1 Motor speed
error 1) Command speed is high. Check if the command
speed is at the
permissible speed or
higher. The command
speed is at the
permissible speed
or higher. Check the operation
pattern.
The command
speed is lower than
the permissible
speed. Check 2).
2) Servo motor operates with
the maximum torque, and
speed overshoot occurs.
Check if the
acceleration torque is
the maximum. Performed with the
maximum torque. Increase the
acceleration/deceleration
time constant, or reduce
the load.
Performed with the
torque lower than
the maximum. Check 3).
3) Servo system is unstable
and oscillating.
Check if the servo
motor is oscillating. Servo motor is
oscillating. Adjust the servo gain by
the auto tuning 1 or the
one-touch tuning.
Reduce the load.
Servo motor is not
oscillating. Increase the acceleration
time constant.
Check 4).
4) The overshoot of speed
waveform occurs.
Check if the overshoot
occurs due to saturated
torque caused by short
acceleration time
constant. Overshoot occurs. Increase the
acceleration/deceleration
time constant.
Overshoot does not
occur. Check 5).
5) Encoder faulty. Check if the alarm
occurs when the actual
speed is under the
instantaneous
permissible speed. Alarm occurs. Replace the servo motor.
Alarm No.: A.32 Name: Overcurrent
Description The flowed current is higher than the permissible current of the servo amplifier.
Detailed
display
Detailed
Name
Cause Checking method Result Action
32.1 Overcurrent
was
detected by
the hardware
detection
circuit
(during
operation) 1) Servo amplifier fault Check if the alarm
occurs even if the
power cables (U, V, W)
are disconnected. Alarm occurs. Replace the servo
amplifier.
Alarm does not
occur. Check 2).
2) Ground fault or short of
the servo motor power
cables
Check if the power
cables themselves are
shorted. Cables are shorted. Replace the power cables.
No problem. Check 3).
3) Servo motor fault Remove the power
cables from the servo
motor edge and check
if short occurs
(between U, V, W and
).
Ground fault occurs
in the servo motor. Replace the servo motor.
Ground fault does
not occur in the
servo motor. Check 4).
4) Fault in the surrounding
environment
Check the noise, etc. An error is found. Take the appropriate
measures according to the
cause.