Mitsubishi MELDAS MDS-C1 Instruction Manual page 275

Power module overcurrent
Alarm No.
The power module's overcurrent protection function activated.
61
Investigation details
1 Check the state of the operation
when the alarm occurs, and check
the repeatability.
2 Check the load state of all motors,
and the starting/stopping frequency.
3 Check the power capacity.
4 Measure the voltage across wires.
• Is the voltage 170V or more even
when the motor is accelerating?
5 Measure the power voltage with a
synchroscope, and check whether
there is any distortion.
• Are there any other devices
causing the power distortion?
6 Check if there is any abnormality in
the unit's ambient environment.
(Ex. Noise, grounding)
Frequency error
Alarm No.
The input power frequency exceeded the specified range.
62
Investigation details
1 Check the state of the operation
when the alarm occurs, and check
the repeatability.
2 Measure the power voltage waveform
during normal operation.
3 Measure the power voltage when the
motor is accelerating/decelerating.
4 Check if there is any abnormality in
the unit's ambient environment.
(Ex. Noise, grounding)
6. Troubleshooting
Investigation results
The alarm occurs immediately after
200VAC is supplied and after READY
is turned ON.
The alarm occurs frequently during
READY ON.
The alarm occurs after continuous
operation for a long time.
The unit is hot.
The total load of all motors exceeds
the rated capacity of the power
supply unit.
The total does not exceed the
capacity.
The power capacity is insufficient.
The specified power capacity is
secured.
The voltage drops to 170V or less
occasionally.
The difference of the voltage across
wires is 10V or more.
The difference of the voltage across
wires is less than 10V.
The power voltage is distorted.
The power voltage waveform is not
abnormal.
No abnormality is found in particular.
The grounding is incomplete.
An alarm will occur easily if another
device operates.
Investigation results
The alarm occurs each time
immediately after the power is turned
ON. Or, the alarm occurs
occasionally regardless of the
operation state.
The alarm occurs only while the
motor is accelerating/decelerating.
The frequency is deviated from
50Hz±3% or 60Hz±3%.
The voltage waveform dips at some
sections.
There is no problem.
The frequency greatly fluctuates
during acceleration/deceleration.
The voltage waveform during
deceleration dips in some sections.
There is no problem.
No abnormality is found in particular.
The grounding is incomplete.
An alarm will occur easily if another
device operates.
6 - 30
Remedies
Replace the unit.
Investigate item 3.
Investigate item 2.
Lower the motor load and operation
frequency.
Investigate item 3.
Increase the power capacity.
Investigate item 4.
Increase the power capacity.
Improve the power phase balance.
Investigate item 5.
Improve the source of the distortion.
Install an AC reactor.
Investigate item 6.
Replace the unit.
Take remedies according to the
causes of the abnormality.
Ex. Incomplete grounding:
Additionally ground.
Noise: Noise measures for
other devices.
Remedies
Investigate item 2.
Investigate item 3.
Review the power facilities.
Improve the source of the distortion.
Install an AC reactor.
Investigate item 4.
Review the power facilities.
Improve the source of the distortion.
Install an AC reactor.
Investigate item 4.
Replace the unit.
Take remedies according to the
causes of the abnormality.
Ex. Incomplete grounding:
Additionally ground.
Noise: Noise measures for
other devices.
CV CR
CV CR