APPENDIXG. ALARM LIST
B–64124EN/01
882
No. CountermeasureDescriptionLED display
[SVU–40, SVU–80]
An overcurrent alarm or IPM alarm is issued.
This alarm is issued in the following cases:
S This alarm is issued when an excessively
large current flows in the main circuit.
S This alarm is issued when an error (overcur-
rent, overheat, low IPM control power supply
voltage) is detected in the IPM (semiconduc-
tor driving the motor).
(1) Check whether a valid motor number is specified in parameter No.30.
(2) Check whether the standard values are specified in the current control parameters for servo
control.
Correct current control is possible only when the standard values are specified for the follow-
ing parameters:
No.70, 71, 72, 78, 79, 84, 85, 86, 87, 88, 89, 90
(3) Turn off the servo amplifier unit for about ten minutes, then release the emergency stop state.
If no overcurrent alarm is issued, The IPM protection function (against overheat) may be oper-
ating. Possible causes of overheat include a high ambient temperature and a too severe mo-
tor operating condition. Check the cause.
– If an overcurrent alarm is issued, go to (4).
(4) Disconnect the power line from the servo amplifier unit connector. Then, release the emergen-
cy stop state.
– If an overcurrent alarm is issued, the IPM protection function (against overcurrent, low con-
trol power supply voltage, overheat) may be operating or defective. Replace the IPM or
servo amplifier unit.
– If no overcurrent alarm is issued, go to (5).
(5) Disconnect the power line from the amplifier connector. Check the insulation between the
ground and each of U, V, and W.
– If a short–circuit is found between the ground and U, V, or W of the motor, replace the motor.
– If the insulation is satisfactory, replace the power line.
(6) Connect the power line. Observe the waveform of the motor current (IR, IS) while the motor
is accelerating or decelerating.
– If the motor current (IR, IS) does not show a normal sine wave, replace the servo amplifier
unit.
(7) Check whether the waveform of the motor current (IR, IS) contains noise.
– If it contains noise, take appropriate measures against noise, such as grounding the shield.
– If it does not contain noise, replace the servo amplifier unit.
(8) If (1) to (7) above are not the cause of the alarm, the pulse coder, command cable, or internal
hardware of the CNC may be defective.