Accidental motor reversal

[inwo]

Found this forum after a quick search for this problem.
I have not taken the time to search this forum.
Hope this is all appropriate!

I have a customer with a lightly loaded 3ph gear motor driving a high inertia rolling load. It is jogged with a wireless remote.

It has been abused for years and I suspect intermittant single phasing from bad contacts.

Customer has told me that motor will "rarely" run in wrong direction. ie. east with west button.

As this problem pre-existed the new radio remote, I suspect that a jog command in one direction, in conjunction with a lost phase and a "rebounding" motor load can possibly allow motor to run in wrong direction.

Is this possible? Probable?

 

[Skogsgurra]

Hi, welcome to the best technical fora in the Universe! (Hmm.. Probably lost some credibility there...)

I think that your analysis is right. A load bouncing/swinging from an earlier movement usually has enough power to start a single-phasing motor in one direction or another. But always in the direction that load pulls. And once started it continues to run in that direction until stopped by thermal protection or command.

So it is not only possible. It is also probable.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

I agree with Gunnar
respectfully

 

[inwo]

Thank you.
I think I'm going to like it here.