11.2 Alarm Displays
11-21
Inspection, Maintenance, and
Troubleshooting
1
1
A.710:
A.720:
Overload
A.710: High Load
A.720: Low Load
Incorrect wiring or contact fault
of servomotor and encoder.
Check the wiring.
Confirm that the servomotor and
encoder are correctly wired.
Operation beyond the overload
protection characteristics.
Check the servomotor overload
characteristics and command.
Reconsider the load conditions and
operation conditions. Or, increase
the servomotor capacity.
Excessive load was applied dur-
ing operation because the servo-
motor was not driven due to
mechanical problems.
Check the command and servomo-
tor speed.
Remove the mechanical problems.
SERVOPACK failure
−
The SERVOPACK may be faulty.
Replace the SERVOPACK.
A.72A:
Converter Electric
Operation Overload
(A continuous operation
drew power at a rate that
exceeded the rated out-
put of the power regen-
eration converter.)
The sequence of phase U, V, and
W motor lines is incorrect.
Check the wiring of the motor’s
main circuit cable.
Correct the motor wiring.
The motor main circuit cable is
either incorrectly wired or has a
contact fault.
Make sure the wiring is correct.
Correct the wiring.
A mistake occurred when select-
ing the power regeneration con-
verter capacity.
Check the power regeneration con-
verter capacity and the total output
capacity of the SERVOPACK.
Change the power regeneration con-
verter capacity.
Converter current detection cir-
cuit failure
−
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the power regeneration con-
verter may be faulty. Replace the
power regeneration converter.
The AC power supply voltage is
low.
Measure the power supply voltage.
Set AC power supply voltage within
the specified range.
A.72B:
Converter Power
Supply Regenerative
Overload
(Continuous power
regeneration exceeded
the ratings of the power
regeneration converter.)
A mistake occurred when select-
ing the power regeneration con-
verter capacity.
Check the power regeneration con-
verter capacity and the total output
capacity of the SERVOPACK.
Change the power regeneration con-
verter capacity.
The AC power supply voltage is
low.
Measure the power supply voltage.
Set AC power supply voltage within
the specified range.
Power regeneration converter
failure
−
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the power regeneration con-
verter may be faulty. Replace the
power regeneration converter.
A.730:
A.731:
Dynamic Brake
Overload
(An excessive power
consumption of dynamic
brake was detected.)
The servomotor rotates because
of external force.
Check the operation status.
Take measures to ensure the servo-
motor will not rotate because of
external force.
The rotating energy at a DB stop
exceeds the DB resistance capac-
ity.
Check the DB resistor power con-
sumption monitor in SigmaWin for
the
Σ
-V-SD (MT) to see how many
times the DB has been used.
• Reduce the servomotor reference
speed.
• Reduce the moment of inertia
ratio.
• Reduce the number of times of
the DB stop operation.
SERVOPACK failure
−
The SERVOPACK may be faulty.
Replace the SERVOPACK.
A.74A:
Converter Inrush
Resistance Overload
(The main circuit power
supply turned ON and
OFF frequently.)
The main circuit power supply
turned ON and OFF frequently.
Check the ON/OFF sequence of the
main circuit power supply.
Change the sequence and operation
pattern such that the main circuit
power supply does not turn ON and
OFF frequently.
Inrush limit circuit failure
−
Turn the power supply OFF and
then ON again after cooling the
power regeneration converter to the
ambient temperature. If the alarm
still occurs, the power regeneration
converter may be faulty. Replace
the power regeneration converter.
(cont’d)
Alarm:
Alarm Name
Cause
Investigative Actions
Corrective Actions