Mitsubishi Electric C70 Setup Manual page 599

MITSUBISHI CNC
Appendix 2 Explanation of Alarms
Power supply: Over regeneration
Alarm No.
Over-regeneration detection level became over 100%. The regenerative resistor is overloaded. This alarm cannot be reset
73 for 15 min from the occurrence. Leave the drive system energized for more than 15 min, then turn the power ON to reset
the alarm.
Investigation details
Check the alarm occurrence state and
regenerative load displayed on the NC
1
Monitor screen while changing the
operation mode.
Check whether the parameter (regenerative
2 resistor type) of the drive unit controlling the
power supply unit is correct.
Check the regenerative resistor's state.
3 [1] Is oil adhered?
[2] Measure the resistance value.
4 Check the alarm No. "75" items.
Power supply: Overvoltage
Alarm No.
L+ and L- bus voltage in main circuit exceeded the allowable value. As the voltage between L+ and L- is high immediately
75
after this alarm, another alarm may occur if this alarm is reset in a short time. Wait more than 5 min before resetting so that
the voltage drops.
Investigation details
1 Check the repeatability.
2 Check the power supply's alarm history.
3 Check the power capacity.
Measure the voltage across wires.
4 [1] Is the voltage 170V or more even when
the motor is accelerating?
Measure the power voltage with a
synchroscope, and check whether there is
5 any distortion.
[1] Are there any other devices causing the
power distortion?
Check if there is any abnormality in the
6 unit's ambient environment.
(Ex. Noise, grounding, etc.)
Alarm No.
Power supply: External emergency stop setting error
76
The rotary switch setting of external emergency stop is not correct, or a wrong external emergency stop signal is input.
Investigation details
1 Check the rotary switch setting.
Check if there is any abnormality in the
2
unit's ambient environment.
582
Investigation results
The regenerative load value increases
when the power is turned ON and the motor
is not rotated.
The regenerative load value increases each
time the motor decelerates, and the alarm
occurs.
The regenerative load value increases each
time the motor decelerates, but the alarm
does not occur when the operation mode is
eased.
The setting is incorrect.
The setting is correct.
The regenerative resistor is abnormal.
There is no problem.
Investigation results
The alarm occurs each time the motor
decelerates.
The alarm occurs occasionally.
Auxiliary regeneration frequency over (E8)
occurs just before the over-voltage occurs.
Others.
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.
Take remedies according to the causes of the abnormality in the ambient environment.
Investigation results
When using external emergency stop,
rotary switch is not set to "4".
No abnormality is found in particular.
The grounding is incomplete.
Remedies
Check whether the state is affected by
power fluctuation, grounding or noise. If
there is no problem, replace the unit.
A-CR:
Check the investigation item No. 2.
C1-CV:
Check the investigation item No. 4.
A-CR:
Check the investigation item No. 2.
C1-CV:
Ease the operation mode.
Correctly set. (Check the alarm No. "6D"
items.)
Check the investigation item No. 3.
Replace the regenerative resistor.
Check the investigation item No. 4.
Remedies
Check the investigation item No. 3.
Check the investigation item No. 2.
Limit the occurrence of the excessive
instantaneous regeneration by not
decelerating multiple axes at the same time.
Check the investigation item No. 3.
Increase the power capacity.
Check the investigation item No. 4.
Increase the power capacity.
Improve the power phase balance.
Check the investigation item No. 5.
Improve the source of the distortion.
Install an AC reactor.
Check the investigation item No. 6.
Remedies
Set the rotary switch to "4".
Replace the drive unit.
Take remedies according to the causes of
the abnormality.
Additionally ground and review.
CV
CV
CV