Mitsubishi Electronics BNP-C3040D Welder User Manual


 
6. Troubleshooting
6 - 36
Alarm No.
75
Overvoltage
The main circuit PN bus voltage exceeded the tolerable value.
Investigation details Investigation results Remedies
CV CR
The alarm occurs each time the
motor decelerates.
Investigate item 3. 1 Check the repeatability.
The alarm occurs occasionally. Investigate item 2.
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Auxiliary regeneration frequency over
(E8) occurs just before the
overvoltage occurs.
Limit the occurrence of the excessive
instantaneous regeneration by not
decelerating multiple axes at the
same time.
2 Check the power supply's alarm
history.
Others. Investigate item 3.
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The power capacity is insufficient. Increase the power capacity. 3 Check the power capacity.
The specified power capacity is
secured.
Investigate item 4.
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The voltage drops to 170V or less
occasionally.
Increase the power capacity.
The difference of the voltage across
wires is 10V or more.
Improve the power phase balance.
4 Measure the voltage across wires.
Is the voltage 170V or more even
when the motor is accelerating?
The difference of the voltage across
wires is less than 10V.
Investigate item 5.
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The power voltage is distorted. Improve the source of the distortion.
Install an AC reactor.
5 Measure the power voltage with a
synchroscope, and check whether
there is any distortion.
Are there any other devices
causing the power distortion?
The power voltage waveform is not
abnormal.
Investigate item 6.
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No abnormality is found in particular. Replace the unit. 6 Check if there is any abnormality in
the unit's ambient environment.
(Ex. Noise, grounding)
The grounding is incomplete.
An alarm will occur easily if another
device operates.
Take remedies according to the
causes of the abnormality.
Ex. Incomplete grounding:
Additionally ground.
Noise: Noise measures for
other devices.
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Alarm No.
76
External emergency stop setting error
The rotary switch setting for the external emergency stop does not match the parameter setting.
Investigation details Investigation results Remedies
CV CR
1 Check the rotary switch settings and
parameter settings.
When using external emergency stop:
Add 0040h to the normal setting for SV036 or SP041, and set the power
supply's rotary switch to "4".
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