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10ee Single Phase Conversion Help

Mobius1ac

Plastic
Joined
Apr 15, 2023
Location
Grand Forks, ND
I recently bought a 1941 Motor Generator 10EE Lathe. I am in the middle of restoring it but have no access to 3 phase power, so I'm trying to get it running on single phase. I will post a picture of the AC motor plate when I get home, but the 240v is covered in stamps and is unreadable and the phase number has both a 3 and a 2 stamped on top of each other.

I have decided to try and keep the original MG setup and have looked into Rotary Phase Converters. A full on converter is expensive, but you can buy just the control panel. If you do this, you need an additional idler motor to get the third phase.

My question is: can you use the AC motor as the idler and run the lathe off of that?
 
If you google converting 10ee to run on single phase, you'll get a link to the Home Shop Machinist site where there's a detailed thread. It's possible, but a bit involved.

If you are really contemplating doing that, you should just build your own rotary phase converter. It would be easier, really. You'd need a 7.5 hp motor for an idler. You can make it fancy with a couple of contactors, pushbuttons and some start and run capacitors, or just get a rope and yank the thing to start before applying power. It will work well enough to run the MG. Lots of threads here and elsewhere on what you need to know.

3 phase motors are one of the most reliable devices ever made. Although it is possible the windings may get toasted, the biggest possible problem with an old motor is bad bearings. Check Craigslist, industrial surplus, auctions or shop sales to find one cheap. I think I paid $35 for the 7.5hp motor in my RPC.
 
If you google converting 10ee to run on single phase, you'll get a link to the Home Shop Machinist site where there's a detailed thread. It's possible, but a bit involved.

If you are really contemplating doing that, you should just build your own rotary phase converter. It would be easier, really. You'd need a 7.5 hp motor for an idler. You can make it fancy with a couple of contactors, pushbuttons and some start and run capacitors, or just get a rope and yank the thing to start before applying power. It will work well enough to run the MG. Lots of threads here and elsewhere on what you need to know.

3 phase motors are one of the most reliable devices ever made. Although it is possible the windings may get toasted, the biggest possible problem with an old motor is bad bearings. Check Craigslist, industrial surplus, auctions or shop sales to find one cheap. I think I paid $35 for the 7.5hp motor in my RPC.
Pull start electric lathe... I like it, lol.

I've seen many of the links, my problem is that the ID plate on my Motor Generator unit has some of the numbers essentially scribbled out including the alternate voltage and the phase and frankly, I am not experienced enough to figure out what it is actually set up as.

I am definitely interested in trying to make my own rotary converter. I can absolutely get another motor, but then I'm going to have an oil pump,3 motors, a generator, and an exciter all crammed into this thing and I think that's a bit ridiculous. My idea is to get the control panel for a rotary converter and use the AC motor since it's like $150 instead of $1200 for a full converter as the idler because that's essentially what it's acting as anyway
 
I recently bought a 1941 Motor Generator 10EE Lathe. I am in the middle of restoring it but have no access to 3 phase power, so I'm trying to get it running on single phase. I will post a picture of the AC motor plate when I get home, but the 240v is covered in stamps and is unreadable and the phase number has both a 3 and a 2 stamped on top of each other.

...
This thread will guide you through the steps to rewire the AC motor to operate on 220:
It's possible that the motor was rewound to be 440 only at some point and can't be converted. There were also a some two-phase 10EEs built. Two-phase power is not to be confused with single-phase; it was (and still is, on a limited basis) in use in the Philadelphia area. The photos in the above link explain how to tell if your machine can be converted to 220.
My question is: can you use the AC motor as the idler and run the lathe off of that?
Yes. A so-called "Static Phase Converter" (SPC), such a those made by Phase-a-Matic (link), allows you to run a 3-phase load motor from single phase, but at about 65% of rated power. An SPC is basically the motor starter part of a Rotary Phase Converter (RPC). They're actually fairly simple devices, consisting of a potential relay and one or more starting capacitors. The relay connects the capacitor(s) to the third phase long enough to get the motor running. It will then run (at reduced power) with power on two of the phases. Adding run capacitors helps balance the motor and improve performance. An idler motor can be added to the SPC to give you an RPC.
 
Please post a photo of the inside of the terminal panel on the front of the motor/generator (MG). There should be nine wires coming into the back of the panel in the upper-right corner. (Those are the wires that come from the winding on the AC motor part of the MG.) There should have metal tags, numbers 1 to 9, on the wires. The wires should either connect to one another or to terminals T1 to T3 (sometimes T4 is also used) on the bottom of the terminal strip, right side.
 
Please post a photo of the inside of the terminal panel on the front of the motor/generator (MG). There should be nine wires coming into the back of the panel in the upper-right corner. (Those are the wires that come from the winding on the AC motor part of the MG.) There should have metal tags, numbers 1 to 9, on the wires. The wires should either connect to one another or to terminals T1 to T3 (sometimes T4 is also used) on the bottom of the terminal strip, right side.
Do you mean this panel?

PXL_20230501_221519373.jpg
 
Yes, that's the panel. I need a better view of the bottom terminals and wiring.

I misspoke before. The hole for the AC motor and DC generator wiring is on the right side, just below center. It's hiding behind the 3 red wires. The red wires and the conduit that they go into are not vintage. Find out where that conduit goes. The conduit on the top right should go to the DC exciter (mounted on top of the MG); are there two or three wires in that conduit?

Are there wire numbers or any other tags on the red wires or the three black wires on terminals T1, T2 and T3, right side?
 
PXL_20230501_224305399.jpg

I'm pretty sure those three wires go to the oil pump. They follow a conduit up to a jury rigged breaker panel(I think) and then go around into the oil pump
 
By "oil pump", I think you mean the optional coolant pump on the back of the base.

I take it that there's no tags on the three black wires?

At this point, it looks like the motor was rewound for 440 only operation, or it could be that they just replaced the leads and connected the windings for high-voltage (440) operation internally. The MG would have to be opened up to see what's going on. Depending on your level of electrical knowledge, you might be able to do that yourself. A motor shop would be able to tell you.
 
It is the coolant pump. I can't see any tags, but I'm also elbow deep in degreaser atm. Cleaning up some of the smaller parts while I wait on my hoist to get the motors out.

I might be able to figure it out if it was just converted and then they scratched out the plate. I'm not great with electrical stuff, but I can carry my own.
 
GrantGunderson went through his MG set, reconditioned everything and replaced the AC section's leads, including bringing out all twelve wires to make it possible to do Steelman single-phase conversion (link). His teardown of the MG set starts here:
Replacing the AC motor's leads starts here:
 








 
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