Chapter 7 Troubleshooting |VFD-B Series

7.2 Ground Fault

GFF

Ground fault

Is output circuit(cable or No

motor) of AC motor drive

grounded?

Yes

Maybe AC motor drive has

malfunction or misoperation

due to noise. Please

contact DELTA.

Remove ground fault

7.3 Over Voltage (OV)

Over voltage

Reduce voltage to

be within spec.

No Is voltage within

specification

Yes

Maybe AC motor drive

has malfunction or

misoperation due to

noise. Please contact

DELTA.

Has over-voltage occurred without load Yes

No

No When OV occurs, check if the

voltage of DC BUS is greater

than protection value

Yes

Yes

No Dose OV occur when

sudden acceleration

stops

Yes

Increase

deceleration

Yes

time

No

Reduce moment

of inertia

Increase

Yes

acceleration

time

Increase setting time

No

No

Reduce moment of load inertia

Need to consider using

brake unit or

DC brake

No

Use brake unit or DC brake

No

Yes

Need to check control method. Please contact DELTA.

7-2

Revision July 2008, BE16, SW V4.08 & V5.00