Fuji Electric ALPHA7, User Manual

Page: 423 / 662

CHAPTER 7 MAINTENANCE AND INSPECTION
7-16
Troubleshooting Method
7
13. Main Power Undervoltage
[Display] [Description of detected alarm]
AL.LuP
The power supplied to the servo amplifier falls below the minimum
specification voltage limit.
[Cause and remedy]
Cause Remedy
The source voltage drops due to
momentary power failure or similar.

Check the power supply environment whether
momentary power failure is generated or not, and
improve the power supply environment.

Check and improve the power supply capacity and
transformer capacity.
The power is turned on or off
intentionally.

Do not turn the power on after the time specified in
PA2_68 (main power shutoff detection time) has
elapsed. (Detection fails after about 2 [s].)
DC input is under execution.

Set PA2_68 (main power shutoff detection time) at 1000
[ms].
If the power supply environment is adverse, PA2_67 (alarm detection at undervoltage) can be
applied to ignore undervoltage detection. In this case, operation can be continued with the setting
of PA2_66 (flying start at speed control) in the event of momentary power failure. Undervoltage
detection is set at about 200 [V] by the DC voltage in the servo amplifier.
14. Internal Regenerative Resistor Overheat
[Display] [Description of detected alarm]
AL.rH1
The power consumption of the regenerative resistor built in the servo
amplifier exceeds the upper limit. (Detection is made at the internal
electronic thermal relay of the servo amplifier.)
[Cause and remedy]
Cause Remedy
Excessive source voltage
(immediately after power-on)

Check if the source voltage is within specification limits.

Insert a reactor if there is a power factor improvement capacitor.
Due to vertical transfer or
winding purpose, etc. the
regenerative power cannot be
consumed.

Increase the deceleration time.

Decrease the servomotor rotation speed.

Increase the cycle time and decrease the operation frequency.

Connect an external regenerative resistor.

Install a counterweight.