Mitsubishi Electric MR-E A Series Instruction Manual page 159

10. TROUBLESHOOTING
Display
AL.31 Overspeed
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AL.32 Overcurrent
AL.33 Overvoltage
AL.35 Command
pulse frequency
error
Name Definition
Speed has exceeded
the instantaneous
permissible speed.
Current that flew is
higher than the
permissible current
of the servo
amplifier.
Converter bus
voltage exceeded
400VDC.
Input pulse
frequency of the
command pulse is
too high.
Cause
1. Input command pulse frequency
exceeded the permissible
instantaneous speed frequency.
2. Small acceleration/deceleration
time constant caused overshoot to
be large.
3. Servo system is instable to cause
overshoot.
4. Electronic gear ratio is large
(parameters No. 3, 4)
5. Encoder faulty.
1. Short occurred in servo amplifier
output phases U, V and W.
2. Transistor (IPM) of the servo
amplifier faulty.
Checking method
Alarm (AL.32) occurs if power is
switched on after U,V and W
are disconnected.
3. Ground fault occurred in servo
amplifier output phases U, V and
W.
4. External noise caused the
overcurrent detection circuit to
misoperate.
1. Lead of built-in regenerative brake
resistor or regenerative brake
option is open or disconnected.
2. Regenerative transistor faulty.
3. Wire breakage of built-in
regenerative brake resistor or
regenerative brake option
4. Capacity of built-in regenerative
brake resistor or regenerative
brake option is insufficient.
5. Power supply voltage high.
1. Pulse frequency of the command
pulse is too high.
2. Noise entered command pulses.
3. Command device failure
10 - 8
Action
Set command pulses correctly.
Increase acceleration/deceleration time
constant.
1. Re-set servo gain to proper value.
2. If servo gain cannot be set to proper
value:
1) Reduce load inertia moment ratio; or
2) Reexamine acceleration/
deceleration time constant.
Set correctly.
Change the servo motor.
Correct the wiring.
Change the servo amplifier.
Correct the wiring.
Take noise suppression measures.
1. Change lead.
2. Connect correctly.
Change servo amplifier
1. For wire breakage of built-in
regenerative brake resistor, change
servo amplifier.
2. For wire breakage of regenerative brake
option, change regenerative brake
option.
Add regenerative brake option or increase
capacity.
Review the power supply.
Change the command pulse frequency to a
proper value.
Take action against noise.
Change the command device.