3. TROUBLESHOOTING AND
TROUBLESHOOTING AND RECOVERY
Type LED Type LED Type LED Remarks
L-axis IPM alarm
M-axis IPM alarm
L-and M-axes IPM
Both figure and
(1) Only the SVU1- 20(A06B- 6089- H102)has a built- in fan. If this fan
stops,an IPM alarm (“8.” in the LED indicator) is issued. So, if this
alarm is issued on the SVU1- 20, first check that the fan is rotating.
A spare of the fan motor can be ordered using the spare list code
A06P- 6089- H102.
(2) After keeping the amplifier switched off for about ten minutes,
release the emergency stop condition.
If the alarm was due to IPM overheat, it will not be issued this
time because the IPM is not hot any longer. The probable causes
of IPM overheat include high ambient temperature and
excessively strict operating condition for the motor.Check for
If the IPM alarm is still issued, go to (3).
(3) Disconnect the power wires from the amplifier terminals, and release
the emergency stop condition.
If the IPM alarm is still issued, the probable cause is the operation
of the IPM protection function (overcurrent or power supply
failure). Replace the IPM or amplifier.
If the IPM alarm is not issued, go to (4).
(4) Disconnect the power wires from the amplifier terminals, and check
the U, V, and W wires for isolation from the grounding wire
If they are isolated from the grounding wire, go to (5) and (6).
If any of the power wires is short- circuited to the grounding wire,
disconnect the power wires from the motor connector, and check the
U, V, and W terminals of the motor for isolation from the ground
If the U, V, or W terminal of the motor is short-circuited to the
ground terminal, replace the motor.
If they are isolated from the ground terminal, replace the power
(5) Connect the wires again,and observe the motor current (IR, IS)
waveforms when the motor is accelerating or decelerating. (See
Section 4.2.2 for how to measure.)
If the motor current waveforms are abnormal, replace the
(6) Check to see if noise is induced on the motor current (IR, IS)
If there is noise, shield the wires and ground the shielding.
If there is no noise, replace the amplifier.
(7) Any of the above six items does not fit the case,the pulse coder,
command cable or the hardware inside the CNC is probably defective.