AB 700 flex drive

AB 700 flex troubleshooting: My VFD is intermittently faulting out my roll table Euro drive motor. I receive a Output phase loss fault (code 21). I switch over to my standby 700 flex, and 3 hours later the same fault. No information in the manual to help. Has anyone experience this please respond.

The manual states it is a loss of current in one phase for an length of time. Most likely a motor wiring issue, loose connection etc.

AB 700 power flex

Ok, that a start, but I have already replaced the Euro drive SEW motor with a new one. Are you suggesting to ring out the leads going back to the VFD, and or control relay contacts.

Check the wiring from output drive to the motor.
It could also be a contactor or relay issue.

Thanks, sounds like weekend work, when we are not running production.

Shouldn't be any relay or contactor contacts in the motor leads, as a general rule.

DickDV said:

Shouldn't be any relay or contactor contacts in the motor leads, as a general rule.

Click to expand...

Yes, but "roll table" and "Eurodrive" evokes a vision of something from Europe with EU safety circuits that, if SIL4, might have an output safety contactor(s) between the drive and motor. A burned contact on that contactor would do it.

What I see happen is that the design INTENT is that the safety contactor is only used in a safety procedure, when the drive is supposed to already be turned off under normal operating procedures. But lazy operators figure out that if they just open an access door or something, the safety circuit shuts the drive down and they dont have to take 3 steps to the right to hit the stop button for a normal shut down routine. The constant opening of that contactor on the output of the drive sets up a race to see who will fail first, the contacts or the drive transistors. But the operators couldn't care less...