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7 Troubleshooting
MITSUBISHI CNC
Alarm No.
62
Power supply: Frequency error
The input power supply frequency increased above the specification range.
Investigation details Investigation results Remedies CV
1
Check the state of the operation when the alarm
occurs, and check the repeatability.
The alarm occurs each time immediately
after the power is turned ON. Or, the alarm
occurs occasionally regardless of the
operation state.
Check the investigation item No. 2.
◯
The alarm occurs only while the motor is
accelerating/decelerating.
Check the investigation item No. 3.
2
Measure the power voltage waveform during
normal operation.
The frequency is deviated from 50Hz±3% or
60Hz±3%.
Review the power facilities.
◯
The voltage waveform dips at some sections.
Improve the source of the distortion.
Install an AC reactor.
There is no problem. Check the investigation item No. 4.
3
Measure the power voltage when the motor is
accelerating/decelerating.
The frequency greatly fluctuates during
acceleration/deceleration.
Review the power facilities.
◯
The voltage waveform during deceleration
dips in some sections.
Improve the source of the distortion.
Install an AC reactor.
There is no problem. Check the investigation item No. 4.
4
Check if there is any abnormality in the unit's
ambient environment.
(Ex. Noise, grounding, etc.)
Take remedies according to the causes of the abnormality in the ambient environment.
◯
Alarm No.
66
Power supply: Process error
An error occurred in the process cycle.
Investigation details Investigation results Remedies CV
1 Check the repeatability.
The alarm occurs each time after the power
is turned ON.
Replace the unit.
The alarm occurs occasionally. Check the investigation item No. 2.
2
Check if there is any abnormality in the unit's
ambient environment.
(Ex. Noise, grounding, etc.)
Take remedies according to the causes of the abnormality in the ambient environment.
Alarm No.
67
Power supply: Phase interruption
An open-phase condition was detected in input power supply circuit.
Investigation details Investigation results Remedies CV
1 Check the voltage for each input phase.
There are phases with no voltage. Correct the power supply.
◯
There is no problem. Check the investigation item No. 2.
2 Check the alarm No. "71" items.
◯
Alarm No.
68
Power supply: Watchdog
The system does not operate correctly.
Investigation details Investigation results Remedies CV
1 Check the repeatability.
The alarm occurs each time READY is turned
ON.
Replace the unit.
◯
The alarm occurs occasionally. Check the investigation item No. 2.
2
Check if there is any abnormality in the unit's
ambient environment.
(Ex. Noise, grounding, etc.)
Take remedies according to the causes of the abnormality in the ambient environment.
◯
Alarm No.
69
Power supply: Grounding
The motor power cable is in contact with FG (Frame Ground).
Investigation details Investigation results Remedies SV SP
1
Measure the insulation across the power cables
(U,V,W) for all motors and the ground. (Carry out a
megger test.)
Less than 100k . (Grounding)
The motor or power cable may be ground
faulted.
◯◯
100k or more. (Normal)
Check the investigation item No. 2.
2
Has oil come in contact with the motor or power
cable?
Oil has come in contact.
Take measures so that oil does not come in
contact. Check the motor's cannon connector
and the inside of the terminal box, and clean
as necessary.
◯◯
Oil has not come in contact. Check the investigation item No. 3.
3 Measure the insulation again.
Less than 1M . (Grounding)
Replace the motor or cable.
◯◯
1M or more. (Normal)
Check the investigation item No. 2.
4
Measure the resistance across the U, V, W phase
terminals of the servo/spindle drive unit and the
ground.
(Do not measure the insulation as the unit could be
damaged.)
Less than 100k .
Replace the drive unit.
◯◯
100k or more.
Replace the power supply unit.
5
Check whether there is any axis in which alarm has
occurred.
There is an axis in which alarm has occurred. Check the alarm No. "24" items.
◯◯
There is no axis in which alarm has occurred. Check the investigation item No. 2.