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Powermatic Model 90 wood lathe motor

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Randy Wentzel

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I am rebuilding a vintage Powermatic Model #90 wood lathe and I am in need of an original electric motor. My lathe used a custom motor manufactured by Robbins & Myer which fit into the bed casting. A standard motor will not work. The original motor was a 1 horsepower, 1725 rpm motor, 5/8" shaft. If anyone would have any leads or have an extra motor in running condition I would be interested
Thanks!
 
Thanks for the reply Mike. I bought the unit without a motor thinking I could put a new motor in it but I didn't realize it was a non standard motor. Didn't do my homework...lesson learned.
 
Can you post a photo of the motor mount or a link to the lathe drive diagram?
Perhaps with a few modifications you could get another motor to work.
I am sure you are not the first to go down this road.
 
20170829_092917.jpg 20170829_092952.jpg

Thanks for the responses. I actually contacted Christian (the gentleman in the You Tube video) as he has an original motor. He doesn't want to sell the motor he has but has given me some pictures and dimensions of the motor. I could fabricate a jack shaft assembly or modify a new motor to move the capacitor and reset switch and junction box but I thought I would try find an original motor first. I have attached the photos he sent. This is a three phase motor so there is no capacitor. I have posted on the forum of the OWWM as well. I will keep looking for a while before I commit to the other options. Thanks!
 
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The attached pdf file shows the typical mounting of the motor to the machine.
It looks like you could fabricate a flat 4-bolt adapter mounting plate for an available motor.
If you can design an adapter plate that will work with a readily available motor this will simplify
the motor replacement going forward. Trying to find an original motor or getting one rewound
can get expensive. The adapter plate will keep the machine original so anyone could still easily
install the factory motor and have a factory original machine.

You could call WWGrainger and give them the motor frame type and they can advise you if there
are any replacement motors that have those specifications. I did see a number of Robbins & Myers
motors on Ebay you would need to look at the listings each week and wait for a motor of the HP and
frame mounting that will work on your machine to show up.

http://vintagemachinery.org/pubs/655/4332.pdf
 
Great project for this winter. Good luck and show us some pictures when complete.
Noticed the motor was originally made in Springfield, Ohio. From an ex-Buckeye.
 
Hi Randy and All, I have an old Powermatic 90 as well. The 220 motor just burned out. I pulled it out and it was a GE 5kc47sg1547x, but it seems to be so old you can't cross reference it. I'm learning that the keys to getting a replacement are to make sure you have the 56 frame (allows you to fit the bolts on the back of the main casting), the cradle base (the cradle base clamps onto the ends of the motor housing with clamp screws that allow you to rotate the motor in the mount so you can align it without the capacitor getting stuck on the main lathe casting or the lathe stand, as compared to the base just being welded onto the cylinder part of the motor), a 5/8 shaft (so the reese drive pulley still fits), and you want the wire leads to go directly into the motor, and not into a big clunky side-mounted junction box, which takes up too much space to fit in the main casting. I believe both the Marathon 5kc49pn0164x and Dayton 6k321k fit. I found a used USA Dayton on Ebay for $75 plus $27 shipping, so I'm crossing my fingers :-) At Grainger, the USA Marathon is about $270 and the Dayton (made in Mexico, if that matters to you) is about $212.

I do not think you can fit a capacitor and a clunky side mount junction box in the main lathe casting.

I don't think you need to do any modification for these two motors (move capacitor, etc.), just run the leadwires in a flexible conduit and a right angle connector into the motor, and the other end to your magnetic switch, set the motor up so when you look at the end of the lathe with the motor shaft facing out toward you, base to the left at 9:00, the capacitor should be about 4:00 (that's how this GE was set up) Then slide it into the lathe casting. It's wicked tight, and there's not too much room to pass the four bolts through the back and get nuts on. I took the headstock off to get more access. When I work on things like this, I wish I had more hands....one day Octopi will rule the world.

Hope this helps!
 
With the motor being enclosed in the cabinet of the lathe you already have the wires
enclosed in an enclosure not open to the elements. Your main concern would be to
secure the wires inside the cabinet so they do not rub on any surfaces and short out.
NEMA, NEC, UL has increased junction box requirements which causes some issues
when replacing old motors that had smaller junction boxes.
 
I have a gold model 90with a 2 hp 3 phase Baldor motor if your interested I am replacing it with a lessor dc motor if your interested.

ED
 
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