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Lathe motor conversion

Posted by woodturner79 (My Page) on
Fri, Jun 10, 11 at 10:44

I was giving a wood lathe recently (Vega bowl lathe). It has a 240v single phase 1.5HP motor in it. The only problem I have with it is the speed control is horrible. It's not a true variable speed, you just tighten or loosen the belt which creates slip and thus speeds up or slows down the headstock.
I've called the company and they offer a DC motor conversion, but it's very expensive. My question is, what would be the best route to go to get true variable speed?

With the motor I currently have I know I'm limited. Single phase (output) VFD's are way too expensive so I know I'm going to have to switch out the motor. I'm looking at either getting a three phase motor and a VFD (single phase in, three phase out), or a DC motor and speed controller. Can anyone offer any advice?

Follow-Up Postings:

RE: Lathe motor conversion

Sounds as if you have surveyed the options very well. A single phase motor does not function well with any VFD unless the motor is designed for such use. Torque will be very low at speeds much below design speed.

RE: Lathe motor conversion

I think I can get around the torque issue with keeping the same pulley set up that it has (a low and high speed pulley system). I just want to be able to control the speeds better.

So what I'd like to do is keep the same pulley system which is changed by switching a belt to either a bigger or smaller pulley, but be able to control the speed range of each pulley better.
The way it is now (according to the manufacturer) is when in low, the speed is 160 to 425 RPM in high it's 800 to 2200 RPM. That's all fine and dandy, but controlling it now via the slip system it currently has, is a real PITA. I'd like to be able to just press a button, or turn a knob and be able to speed it up or slow it down.
If I can pull it off (and I understand correctly) in theory I should be able to go from 0-425 in low and 0-2200 in high. Low providing me more torque when first truing up a piece.

RE: Lathe motor conversion

No way to fit stepped pulleys?

RE: Lathe motor conversion

I probably could, but when turning a piece I HATE (LOATHE) stopping and fooling around with belts and crap. I want to just be able to crank up the speed right then and there.

The thing is I don't know enough about motors to just buy one and slap it in.

RE: Lathe motor conversion

find an treadmill with a DC motor..ideally one with the same size shaft. grab the motor controller too..

you might have to make a mounting bracket for the motor.

I change my Nova lathe to use a DC motor and the step pulleys.
it makes for a nice setup


RE: Lathe motor conversion

That's the thing, I don't know what the shaft size is. I have all the specs of the motor that's currently in there, but I can't for the life of me find anything about the shaft size.
I've looked it up on the motor manufacturer's website but couldn't find anything either. I'm hoping someone here (that's in the know about motors) will see this and tell me what I'd need to get to achieve what I'd like to do.

Anyway what's in there now :
Baldor 1.5 HP
Cat # L3514
Spec - 35J385X944
Volt - 115/230
Amps - 8/18
RPM - 1725
Frame - 56/56H
Enc - TEFC

So what I'm looking for is a DC equivalent with a speed control. I know I probably won't find something that is a perfect match that I can just bolt right in, but I would like at least the shaft size to be the same so I can keep the same pulleys that I currently have.

who would have thought just controlling motor speed would be such a PITA.....

possible motor's

I was looking at something like this

it's very cheap, and then I'd get a 3 phase VFD for it. but the frame isn't a TEFC, would that be an issue with heat? THe motor will be running sometimes for several hours if I'm turning a big bowl or something. The only DC motor I could find is way expensive.
Almost seems like I could get a 3 phase motor and a VFD for cheaper than a DC motor and controller

RE: Lathe motor conversion

The standard shaft diameter for Frame 56/56H is 0.6250-- 5/8".
At some point, you must choose between the convenience you seek and the cash in your pocket. The choice will be which you desire the most.

RE: Lathe motor conversion

I know, I'm more than prepared to fork out the cash. I just want to make sure that when I do I'm getting the best bang for my buck, and something that's actually going to work.
I don't want to get the wrong motor and then have to fork out a ton of money for extra machining or whatever.

RE: Lathe motor conversion

TEFC is more an issue with sawdust getting into the motor.

It will tend to stick on the windings and cause the temperature to rise.
For single phase motors it can be a hazard since the start winding throw out switch WILL generate a spark when opening, and in a dusty location is a fire hazard 3-phase motors do not have start windings or throw out switches to disconnect them).

RE: Lathe motor conversion

so do you think an ODP enclosure motor would be better then?

I can get a 3 phase, same frame, ODP motor for $60 and then get a VFD

RE: Lathe motor conversion

ODP is 'Open Drip Proof.'

If you are wiling to make sure dust does not build up it might be acceptable.

RE: Lathe motor conversion

dust is going to happen. I run a wood shop after all.

But you were saying TEFC wasn't a good option either.

RE: Lathe motor conversion

TEFC (Totally Enclosed Fan Cooled) is preferred for things like a wood shop.

I guess my previous post was not clear,'

TEFC prev3nts anything working its way into the motor.

All the open frame types have dust buildup issues within the motor and windings.

They are just more expensive.

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