Mitsubishi Electric C70 Setup Manual page 579

MITSUBISHI CNC
Appendix 2 Explanation of Alarms
Excessive speed error
Alarm No.
A difference between the speed command and speed feedback was continuously exceeding 50 r/min for longer than the
23
setting time.
Investigation details
Check the U, V and W wiring connected to
1
the spindle drive unit.
Check the spindle parameter SP020,
SP026, SP027, from SP057 to SP064 and
2
spindle specification parameters from
slimit1 to slimit4 setting value.
Measure the acceleration/ deceleration time
from 0 to the point where the spindle speed
reaches its maximum.
If the alarm occurs when forward run is
3
changed to reverse run, measure the
acceleration/ deceleration time from the
forward to reverse. Also measure it from the
reverse to forward.
Check the load amount when the alarm
4
occurred during cutting.
Check the fluctuation of the input voltage
5
into the power supply unit with a tester.
6 Check the capacity of the drive unit.
Alarm No. Grounding
24 The motor power cable is in contact with FG (Frame Ground).
Investigation details
Measure the insulation across the power
cables (U,V,W) for connected motors and
the ground. (Carry out a megger test.)
1
(Note)
When the insulation is measured,
disconnect wires from the drive unit.
Has oil come in contact with the motor or
2
power cable?
3 Measure the insulation again.
Measure the resistance across the U, V, W
phase terminals of the servo/spindle drive
4 unit and the ground with a tester.
(Note) Do not measure the insulation as the
unit is damaged.
562
Investigation results
The wires are not correctly connected.
The wires are correctly connected.
The correct values are not set.
The correct values are set.
12sec or more.
(SP117 setting value or more.)
Less than 12sec.
The speed deterioration due to load amount
has exceeded the tolerable range which is
determined by the parameter SP096.
-If SP096 is set to 0, it is regarded as 85%.
Thus a speed of 85% of the machining
speed or faster will be the tolerable speed.
The load amount is within the SP096 setting
value.
Voltage drop during acceleration is 200V or
less
Voltage drop during acceleration is 200V or
more
The capacity does not satisfy the motor
output.
The capacity satisfies the motor output.
Investigation results
Less than 1M .
1M or more.
Oil has come in contact.
Oil has not come in contact.
Less than 1M .
1M or more.
Less than 100k .
100k or more.
Remedies
Correctly connect.
Check the investigation item No. 2.
Correctly set.
Check the investigation item No. 3.
Increase the spindle acceleration/
deceleration time constant setting
value(sp_t1 to sp_t4).
Reduce the load inertia.
Check the investigation item No. 4.
Reduce the cutting load to mitigate the
speed deterioration.
Replace the tool.
Check the investigation item No. 5.
Review the power supply capacity.
Check the investigation item No.6.
Change the capacity to the selected one.
Replace the unit.
Remedies
The motor or power cable may be ground
faulted.
Check the investigation item No. 2.
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.
Check the investigation item No. 3.
Replace the motor or cable.
Check the investigation item No. 4.
Replace the drive unit.
Replace the power supply unit.
SV SP
SV SP