CHAPTER 7 MAINTENANCE AND INSPECTION

7.3 Troubleshooting Method

1. Overcurrent

[Display]

[Description of detected alarm]

oC1

The output current of the servo amplifier exceeds the rated value.

oC2

OC1:

OC2:

Direct detection by internal transistor of servo amplifier

Indirect detection with software of servo amplifier

[Cause and remedy]

Cause

Remedy

Wrong servomotor output wiring

Short circuit or grounding fault in

servomotor output wiring

Correct the wiring of power cables (U, V and W).

Check cables visually or through continuity check

and replace the defective cable.

Servomotor insulation fault

Measure the insulation resistance. (Several MΩ or

over to ground)

Failure of servomotor

Measure the resistance across cables. (Several Ω

between cables)

7

Incorrect resistance of regenerative resistor

Replace with the regenerative resistor within the

rating.

Current imbalance caused by an encoder

fault

Replace the servomotor.

Unconnected grounding cable

Connect the grounding cable.

2. Overspeed

[Display]

[Description of detected alarm]

oS

The rotation speed of the servomotor exceeds 1.1 times the maximum

speed.

[Cause and remedy]

Cause

Wrong servomotor output

wiring

The rotation speed of the

servomotor overshoots.

Remedy

Correct the wiring of power cables (U, V and W).

Check the speed waveform during acceleration with the PC

Loader or similar (see the figure below) and take the following

countermeasures.

 Increase PA1_15 (auto tunimg gain 1).

 Increase PA1_37 (acceleration time).

 Increase PA1_52 (S-curve time constant).

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7-6 Troubleshooting Method

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