The VFD is giving Ground Fault ... What might be the possible reasons ?

[danishdeshmuk]

The VFD is giving Ground Fault ... What might be the possible reasons ?
[FONT=times new roman, new york, times, serif]The VFD is Allen Bradley PowerFlex 400[/FONT]
[FONT=times new roman, new york, times, serif]
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[FONT=times new roman, new york, times, serif]1) Any Phase inside the terminal of motor is touching with the motor frame or body.[/FONT]
[FONT=times new roman, new york, times, serif]2) An phase inside the connection terminal strip of VFD is touching with metallic frame or metallic body of VFD.[/FONT]
3) Any phase is touching with other phase inside the motor terminal
4) Any phase is touching with other phase inside the VFD terminal connection strip
5) Any phase is touching with earth cable (wire) inside the motor terminal
6) Any of the phase is touching with earth cable (wire) inside the VFD
7) Motor's insulation becomes weak.
8) Motor's winding is touching the frame or body of the motor.
9) Any phase is touching the other metallic part or frame or body in between motor and VFD (somewhere).


Are these above mentioned reasons cause of Ground Fault ?


Are these all those possible reasons which cause the Ground Fault to display on VFD LCD ?


Is there any other possible reason of displaying Ground Fault on VFD display ?

 

[weressl]

The VFD is giving Ground Fault ... What might be the possible reasons ?
The VFD is Allen Bradley PowerFlex 400


1) Any Phase inside the terminal of motor is touching with the motor frame or body.
2) An phase inside the connection terminal strip of VFD is touching with metallic frame or metallic body of VFD.
3) Any phase is touching with other phase inside the motor terminal
4) Any phase is touching with other phase inside the VFD terminal connection strip
5) Any phase is touching with earth cable (wire) inside the motor terminal
6) Any of the phase is touching with earth cable (wire) inside the VFD
7) Motor's insulation becomes weak.
8) Motor's winding is touching the frame or body of the motor.
9) Any phase is touching the other metallic part or frame or body in between motor and VFD (somewhere).


Are these above mentioned reasons cause of Ground Fault ?


Are these all those possible reasons which cause the Ground Fault to display on VFD LCD ?


Is there any other possible reason of displaying Ground Fault on VFD display ?

Supply transfomer is a resistance grounded or ungrounded system.

 

[danishdeshmuk]

The above stated causes aren't the ones that can or that do cause Ground Fault ??

 

[Ragin Cajun]

Begin by disconnecting the motor conductors at the VFD.

That either clears the VFD or points to it.

You may want to check with AB regarding possible negative reaction between the drive ground fault circuit and the resistance ground system, it that's what you have.

RC

 

[Jraef]

GF protection in a drive is done with the Residual Current Detection method only on the output of the drive to the motor, not the input. It is looking for a mismatch in the current going out and the current coming back between phases. If some part of the circuit is going to ground, not all of the current returns to the sensor and it the drive trips.

Disconnect the drive and megger the motor circuit. If it's not there, then it's possible that one of your output transistors has failed. Usually that indicates differently on the VFD fault display, but sometimes it's a race to see what is detected first, and the GF wins.

 

[danishdeshmuk]

GF protection in a drive is done with the Residual Current Detection method only on the output of the drive to the motor, not the input. It is looking for a mismatch in the current going out and the current coming back between phases. If some part of the circuit is going to ground, not all of the current returns to the sensor and it the drive trips.

Disconnect the drive and megger the motor circuit. If it's not there, then it's possible that one of your output transistors has failed. Usually that indicates differently on the VFD fault display, but sometimes it's a race to see what is detected first, and the GF wins.

but the ones that i stated above might be the causes or not ?

You're saying if motor's insulation is right after meggering the motor by disconnection it from VFD then there must be a problem inside the drive itself and one of the output transistor is failed.

Is that transistor open or shorted ? OR just becomes weak ?

thanks