Pissed and frustrated. ....contactor issue?

Welder6131 · Sep 29, 2015

Just hooked up my RPC and I'm getting 240 on legs 1 and 2 and leg 3 is fluctuating between 234 and 255V. Cleaned my motor starter contacts and checked my transformer output which was about 125v on my lathe. I have to manually push my contactors in to get the magnetic starter to engage, but lathe motor will only run for a few minutes before kicking out. Double checked motor wiring which was good. If I press the start stop buttons I get nothing.

Where Do I go from here, would motor heaters cause this?

metalmaster10 · Sep 29, 2015

Pissed and frustrated.... That could be a whole thread...
But I will not share mine and let you keep your thread intact.
Good luck on your search.

TDegenhart · Sep 29, 2015

You should change your title to something more discriptive, else boss might lock as meaningly title.

Can you post a diagram of how you have the RPC/lathe wired?

Tom

rons · Sep 30, 2015

Welder6131 said:
Just hooked up my RPC and I'm getting 240 on legs 1 and 2 and leg 3 is fluctuating between 234 and 255V. Cleaned my motor starter contacts and checked my transformer output which was about 125v on my lathe. I have to manually push my contactors in to get the magnetic starter to engage, but lathe motor will only run for a few minutes before kicking out. Double checked motor wiring which was good. If I press the start stop buttons I get nothing.

Where Do I go from here, would motor heaters cause this?

In your pissed and frustrated state you assume we understand your situation.

Leg 3 is between 234 and 255, not too bad.

Yes, contactor overload heaters would cause this. Are they on the idler or the lathe motor.
A picture or drawing would be nice.

Welder6131 · Sep 30, 2015

The issue seems to be occurring at the lathe starter. RPC seems to be in good running order. The lathe ran no problems when I purchased (hooked up to 3 ph). I changed motor wiring on motor to 208v and confirmed it was correct multiple times. The heaters in question are at the lathe......how do I confirm these are bad?

Red James · Sep 30, 2015

"I changed motor wiring on motor to 208v" implies the lathe was wired for high voltage, like 480 volts; the contactactors would be sized for the lower current required for the higher voltage, so that is what is likely the problem.

Richard King · Sep 30, 2015

I had a machine once with a similar issue and they found a bad control voltage transformer. Also some of the old motors wired star or delta...maybe check that out. http://www.pcbheaven.com/userpages/check_the_windings_of_a_3phase_ac_motor/

johnoder · Sep 30, 2015

Nothing bad about he heaters, they just won't handle the double sized amps required by the lower voltage. Always the "second part" of reconnecting a motor for lower volts is to address them

As to contactor not pulling in, see if you are actually feeding the coil the volts that are specified on same

JST · Sep 30, 2015

Yep. Read the guidelines. closed for meaningless title.

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Pissed and frustrated. ....contactor issue?

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TDegenhart

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rons

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Welder6131

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Red James

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Richard King

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