Van Norman 12

[Scra99tch]

Just got the 3PH rotary converter hooked up to the machine. What I am noticing is that the motor seems sluggish. Not going at its full potential. With these 80 year old windings I figure there may be some breakdown but if I have it right each winding to itself measures good at about 2.6 ohms.

Each winding to its neighbor is running at 240 volts UV VW UW etc etc.

I have not measure each winding to the frame but I should be getting open as in no resistance.

After about 3 mins of running the thermal breaker will trip.

Any suggestions? I will end up pulling contacts and giving a good clean.

Thanks

 

[OTmachine]

If Allen Bradley, heaters may be wrong. Was machine wired for 440V 3 ph at one time?

 

[markba633csi]

Heaters could explain the tripping but not the sluggishness- must still be a wiring error
Shoot a pic of the motor terminal connections and/or dataplate

 

[Scra99tch]

Here is the plate and I can confirm three wires in the motor junction box are tied. And each of the ones I clipped from the line in were tied together.

I pulled the 6A heaters from underneath and they look good and intact. If that’s what I was looking at. Bent piece of metal with a heavy gauge wire wound around them.

 

[Scra99tch]

Junction box.

Far left red was my guess 4-5-6 tied in. I did not put the lines in back in the correct position but figured this would result in only a reverse running motor.

 

[OTmachine]

There is a website that explains Delta & Wye wiring with resistance checks that you can do with a VOM to find out which wires are which. Found it when I was looking for info on meggaring a new/ used motor. Just do not remember off the top of my head. Perhaps, @markba633csi knows. If I get a chance later tonight, I will look. Insulating the shop at the moment, (need more Warm workspace).

 

[markba633csi]

It's possible your guess as to 4,5,6 is incorrect
I did find this which might help- if you have the phasing wrong on one or two of the outer windings it would cause the problem you are having
The motor could be fighting itself. A quick proof of that would be to disconnect/separate 4,5,6 and see if the motor runs ok (at 1/2 the HP)
You have a "Y" (star) motor:

Identify unmarked leads on a 9-lead motor

How would I go about identifying unmarked leads on a 9-lead motor? I also need to establish whether this is wired delta or Y.

electronics.stackexchange.com

You can use another source of DC instead of a lantern battery- like a wall-wart power supply or battery charger of 6 to 12 volts dc.
The idea is to briefly touch the power to the winding and note the deflection of the meter on the other winding.
It's called "flashing" the windings.
Requires an analog needle-type meter- a cheap Radio Shack one would be fine
This model is good- I use one of these all the time:

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[Scra99tch]

So I scrubbed at the contacts. Rechecked that the wires were together in WYE.

Tried it again and it still struggled for a moment but then wound up to full speed. I’m thinking just stiff grease was the culprit but a ancient motor probably has something to do with it.

 

[OTmachine]

Did you size your rotary to your motor?

 

[Scra99tch]

Yeah the rotary is 10HP.

I think the spindle is 2hp and feed 1/2hp