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View Full Version : And no we have a possible motor wiring problem!



Buckshot
07-25-2008, 03:44 AM
I had posted a request for help on 7-22 in getting a Teco-Westingouse VFD setup on my new Enco 9x42 mill. Main question was about going through the rotary switch that came on the mill, or wiring direct to the motor. I also had those nagging questions answered in trying to figure out the manual that came with the VFD.

I decided to use the controls on the VFD rather then wire for and buy remotes. In going to wire up the motor I opened the box on the side and there were 6 wires + gnd. Ah, the motor reverses too. These are labeled 1U, !V, & 1W, then there is 2U, 2V & 2W, plus the ground. Ah crap, NOW what?

Even though the motor is a Golden Jubilee Happy Life (rough translation I'm sure) unit from the Peoples Electric Motor Co of Hangten China I called the good folks at Teco-Westinghouse, .............again:-) In the manual that came with the mill it is a reversing 220v 3~ 1720/3400 rpm motor. The tech rep said he wasn't a motor guru but said he knew who to ask, so he put me on hold a moment.

I was told to wire:
W2 to U1 = T1
U2 to V1 = T2
V2 to W1 = T3

And if the motor runs the wrong way to swap any 2 legs.

I jumpered as above and hooked the T1, T2, & T3 up to the VFD. I ran the frequncey up to 30 IIRC, and punched the START button. While the motor ran, I didn't think it was running fast enough. Plus the motor was making a repeating sound like something was hitting something. The fan cover over the motor had a small dent in it from where the head had been laid over onto a styrofoam block on the table for shipment. The sound was such that I thought one of the fan blades was hitting it.

Took the cover off, and that wasn't it. While it DOES sound a bit mechanical, I don't think it is. I went to the VFD and reprogramed the stop from a "Ramp Down" to "Coast to Stop". When you press START the hitting sound speeds up with the motor. Most importantly, now when you press STOP, the sound stops and the motor quietly coasts to a stop.

Also when the motor ran it would run about 2 minutes then stop, and the VFD displays a code ( OL1) which is supposed to be "Motor Overload". I checked both input lines L1 & L2 and they show 110v each. I checked each of the 3 motor leads T1, T2, and T3 with the motor running and they show 150v on each leg (to ground).

My question is to any of you motor theorists or gurus, does the mentioned wiring jumpers look right? I hate to ask the people at Teco -Westinghouse again, cause that ain't their motor! I WIll call them tomorrow and go over all my programing inputs. Those few I changed from the factory presets may possibly be suspect. The folks at the shipping point for the mill supplied a complete check sheet and several of them were (supposedly) powered checks. If the motor was making this noise I can't see them shipping it.

So once again I'm craving a bit of input!

Rick

macona
07-25-2008, 04:01 AM
I dont think the tech gave you the right info. I dont think he understood its a two speed motor. I think one set of wires if for one speed and the other is for the other speed. Try connecting U,V,W1 to the VFD alone and cap the other wires. I think it should run fine. Then figure out which set is the 3400 RPM set and use those wires.

By using both sets of wires you were overloading the motor causing the VFD to error out.

J Tiers
07-25-2008, 08:24 AM
So, there isn't any diagram on the motor?

Not nice of the "People" to keep that information away from the bourgeoisie :rolleyes:

if it is a 2 speed motor, it can only achieve that by having effective 2 poles in 3400 and 4 poles in 1750 rpm.

That can be done by tapping the motor windings and using part of them at high speed, and all at low speed. I have a 1ph motor on a filing machine that has two speeds. You move one line wire to change speeds.

See if your ohmmeter shows a connection between them, with one set showing a lower resistance than the other. If so, try choosing one or the other and do not parallel, you probably have the tapped winding setup.

Buckshot
07-28-2008, 03:58 AM
I dont think the tech gave you the right info. I dont think he understood its a two speed motor. I think one set of wires if for one speed and the other is for the other speed. Try connecting U,V,W1 to the VFD alone and cap the other wires. I think it should run fine. Then figure out which set is the 3400 RPM set and use those wires.

By using both sets of wires you were overloading the motor causing the VFD to error out.

Macona's suggestion cured the problem! However I would also like to exend my humble thanks to everyone who also contributed their thoughts and suggestions to my questions. I was really bummed about having a new machine I'd been lusting after for years, but couldn't use!!

I hooked the 3 wires from the VFD up to the "2" prefixed U, V, W posts, held onto my butt and pushed the START button on the VFD. The freq had been set at 50 and the motor quietly spooled up and hummed along. I wasn't mentally ready for success so I just stood there and stared at it (I think the term is 'Agog'?) while I sorted out possibilities as to what I might be seeing.

I finally settled on 'Success' as what I was seeing. In fact I was so excited I forgot myself and went to get my wife and drag her out to show her too. As many of us know, this can be pretty much a waste of time, but I was still in a bit of denial and needed confirmation by an uninterested party. She didn't waste any time in leaving, so I got to play with the VFD a bit.

I went to the F4 function with is motor rotation and changed the code from 1 to 0 to reverse it. The motor smoothly slowed, came to a stop then immediatly accelerated in the opposite direction. HOT DAMN! Two button pushes and it's reversed. Then I ran the freq's up and down just to see the thing work.

I'm happy :-)

Thanks to all,
Rick