source for IEC metric 3 phase motor

[Richard Coers]

Many of the Eaton motor starters fail in Minmax Centauro bandsaws, and I did replace this starter and coil when the earlier one failed. I will check the voltages at the motor to make sure all 3 phases are present. I can also check the starter connections to make sure the starter should pass enough current. Maybe I should also swap the 3 phase circuit breakers in the load center to make sure the circuit breaker is not limiting the current?? Or plug the bandsaw into one of the other 3 phase receptacles if I can reach it??

Dennis

I'd put jumpers around the magnetic starter and turn on the saw with the circuit breaker before I looked for a mechanical issue now. The actual contacts in the magnetic starter could be bad. In the old days we would use a tiny ignition file and clean up the contacts. I'm betting on unequal current to all 3 phases now.

[Bill Dufour]

Use a megger to test the motor windings. If the starter is a known issue jump around it and see.
Bill D

[Jason Roehl]

The breaker can’t “limit the current” all it can do is open under overload conditions.

Check voltages at the motor under load, you may have a very low voltage on one phase.

Regards, Rod.

A breaker can't limit the current, but a multi-pole breaker can fail on one leg, causing all sorts of weird things to happen. I had it happen on a two-pole 240V breaker for my electric dryer a few years ago. The dryer would run the drum and blow, but would not heat. I started poking around with a voltmeter, and found that the Pushmatic breaker had failed open on one leg. Even with no wires attached, it would not close with a reset. Fortunately, my wife's coworker (they work at an electrical supply company) had a 30A Pushmatic 2-pole breaker in his personal supply at home, for whatever reason. Cost me a couple beers for him to bring it by.

[Ron Selzer]

A breaker can't limit the current, but a multi-pole breaker can fail on one leg, causing all sorts of weird things to happen. I had it happen on a two-pole 240V breaker for my electric dryer a few years ago. The dryer would run the drum and blow, but would not heat. I started poking around with a voltmeter, and found that the Pushmatic breaker had failed open on one leg. Even with no wires attached, it would not close with a reset. Fortunately, my wife's coworker (they work at an electrical supply company) had a 30A Pushmatic 2-pole breaker in his personal supply at home, for whatever reason. Cost me a couple beers for him to bring it by.

Had the same issue at a cousin's house, except it was late 1970's. Had a Pushmatic breaker on the truck, switched it out and dryer worked great again.
Ron

[Dennis Yamamoto]

The breaker can’t “limit the current” all it can do is open under overload conditions.

Check voltages at the motor under load, you may have a very low voltage on one phase.

Regards, Rod.

I understand that the breaker should be able to pass its full rated current unless tripped by an overload. I was wondering if a failing breaker could be ON but not pass its rated current. Probably not!

I did check the voltage at the motor between all three phases with the saw running. All three are 247 volts. I can't hold the multimeter probes on the motor and try to do a thick resaw at the same time. I need someone else to help.

Thanks

[Dennis Yamamoto]

Phase perfect recommends replacing the capacitors every three years.
Bill D

Three other 3-phase machines are running fine, so it is not the Phase Perfect.
I did, however, replace the capacitors a few years back.

Thanks