Thread: MG worries - 53 EE spin up

I have a 440 volt machine that I hooked up to 440V Hit the switch and it was WAY LOUD. The machine has been sitting for over a decade. Is it possible someone rewired it for 220? How can I tell?

Thanks

Jason

Okay, I ran it a few more short bursts, it sounds like the lower motor has a spoon caught in it. Speed seems to be okay. Could it be bearings?

Ahh, the sound of a MG at idle... not pleasant. That's why mine will be located remotely, they're LOUD when all is well.

Some 440 volt machines use a motor that can't readily be connected for another voltage, more are 220/440 volt motors. To check remove the bottom front cover from the base to expose the MG connection box. Remove the cover from the connecton box. If it has been left originial there will be a cardboard tag clipped to the wiring from Reliance showing the voltage it was connected for when it left the factory.

Wrote the above before your "spoon" comment. Dry bearings can make a hellacious noise. Since your machine sat for so long it's plausible the grease/lube in the bearings no longer resembles a lubricant. Did you add oil or grease to them? Could be someone replaced them in the past with sealed units, if so adding lube through the fittings won't help.

If you have a mechanic's stethoscope listen to the MG bearing locations, that will tell you lots.

I did not even look on the back side of the cover. I found this as well as took a shot of the connection box. Tell me what you think.

Here are the same images in high res:

http://i61.photobucket.com/albums/h5...nectionbox.jpg

http://i61.photobucket.com/albums/h5...HDRIVE0001.jpg



Thanks

It appears to be a dual voltage motor with nine leads brought out. From the appearance of the connections: three two wire pairs joined together separately and single wires going to the T1, T2 and T3 connections it is connected for 440 volts.

You can verify it by telling us what the lead numbers are and how they're connected.

FWIW, if it was connected for 220 volts there would be two leads connected to each of the T1, T2 and T3 screws and a single separate connection of three wires connected together.

Yes, I agree with DaveE907. The photos show the machine is wired for 440V. However, the drawing seems to follow a convention I have not seen before, but I am not an electrician.

The motor connections on the right are labeled 1,2,3,...,9, and it says Line for T1,T2 & T3, as expected. The schematic on the left shows T1,T2 and T3 as the motor connections, and shows them connecting to T1,T2 and T3 in the panel. So that would be fine if 1,2,3,..9 were actually in the motor's electrical box and not brought out to the panel. Yes it ends up the same but it is definitely counter to expectations.

-Dave

Check the Cutler-Hammer contactor inside the enclosure on the rear of the machine, behind the headstock.

Note the coil voltage. It should be 460 for your machine, as it is presently connected for 460 volts.

You will need a 230 volt coil when you reconnect the machine for 230.

Brazil Electric in Portland, OR may be able to help you.

Most machines are "plumbed" for application of grease at convenient locations.

I suppose it is possible that a P.O. substituted sealed bearings, but why do so when the plumbing is already there?

The dc spindle motor is similarly plumbed.

"I suppose it is possible that a P.O. substituted sealed bearings, but why do so when the plumbing is already there?"

There have been several studies including government directives in some cases to do away with manual greasing of bearings, particularly with electric motors.
What happens is, over greasing, incorrect grease causing chemical reaction with old grease, failure to remove drain plugs "if so equipped".
This is the worst case, a maintenance person pushes grease too fast into a bearing compartment crushing the metal bearing shield into the races and balls, resulting in rapid bearing failure.
Hand pump grease guns can develop over 1000psi.
So, apply grease very slowly and not over do it.