YASKAWA UAK series User Manual page 270

11 Inspection, Maintenance, and Troubleshooting
11.2.3 Troubleshooting of the Servo Drive Alarms
Alarm:
Alarm Name
A.400:
Overvoltage
(The DC-bus voltage
inside the SERVO-
PACK is abnormally
high.)
11-16
Cause
• For 200-VAC SERVOPACKs
with DC-bus power supply
input: The power supply volt-
age exceeded 410 V.
• For 400-VAC SERVOPACKs
with DC-bus power supply
input: The power supply volt-
age exceeded 820 V.
The power supply is unstable, or
was influenced by a lightning
surge.
Acceleration/deceleration was
executed under the following
conditions.
• The AC power supply voltage
of 200-VAC SERVOPACK
was in the range between 230
V and 270 V.
• The AC power supply voltage
of 400-VAC SERVOPACK
was in the range between 480
V and 560 V.
The moment of inertia exceeded
the allowable value.
SERVOPACK failure
Investigative Actions
Measure the power supply voltage.
Measure the power supply voltage.
Check the power supply voltage and
the speed and torque during opera-
tion.
Confirm that the moment of inertia
ratio is within the allowable range.
−
(cont'd)
Corrective Actions
Set AC/DC power supply voltage
within the specified range.
Improve the power supply condi-
tions, and turn the power supply ON
again after installing a surge
absorber. If the alarm still occurs,
the SERVOPACK may be faulty.
Replace the SERVOPACK.
Set AC power supply voltage within
the specified range.
Increase the deceleration time, or
reduce the load.
Turn the control power OFF and
then ON again while the main cir-
cuit power supply is OFF. If the
alarm still occurs, the SERVO-
PACK may be faulty. Replace the
SERVOPACK.