Convert Lathe Motor to 3-Phase?

[Gaffer]

I've previously posted that I'm cleaning up my Colchester Master 6.5 (13") lathe. A previous owner bypassed the front control panel and reverse switch. It's a bit of a paint figuring out the motor wiring. It's the factory motor - GE 220V 1-phase. The more common option back then was 3-phase. I found on CL a Baldor 3-phase for $75 (said to be in excellent condition), and am now considering buying it and adding a VFD. I know just enough about this to make a bad decision and get into trouble. Both motors have the same size shaft, RPM, and HP. Is this a bad idea? Note the difference in HP - is this an issue? Here are the photos of the ID plates.

 

[markba633csi]

Doesn't list the HP on the Baldor- says "SPL" which means special I'm guessing
I don't know what that means- is it listed in the Baldor catalog?
Why are you switching motors anyhow?

 

[cathead]

The lathe already runs at various speeds so I can't see there is much to gain here. On the minus side,
your pocket book will suffer.

 

[Gaffer]

Doesn't list the HP on the Baldor- says "SPL" which means special I'm guessing
I don't know what that means- is it listed in the Baldor catalog?
Why are you switching motors anyhow?

IDK - just a thought. You and I have discussed identifying the motor wires - primary and start coil wires. My wires are numbered, but there is no wiring diagram for them. It sounds like it's worth the effort to figure it out, and I'm fine with it. Between the motor and VFD purchase, it is a hit on the pocketbook.

 

[markba633csi]

Buying a used motor is always risky- did we discuss your original motor before? Point me to the thread or tell me the date- where did we leave off?
If you need help with the original motor I can assist

 

[Gaffer]

Buying a used motor is always risky- did we discuss your original motor before? Point me to the thread or tell me the date- where did we leave off?
If you need help with the original motor I can assist

Wiring Help Needed

I need help wiring my Colchester Master 6.5 lathe motor. The motor ran fine before diving into this project. I don't know why a previous owner bypassed the main electrical panel, safeties, and reverse switch, but he did. I am hoping that I can understand what connections to make at the motor...

www.hobby-machinist.com

 

[lordbeezer]

3 phase motors with spl for hp rating are off commercial or medical treadmills. For some reason they don’t do hp. Have to go to treadmill specs to get advertised hp which is rated higher than it is.most are rated 4 hp on ads but most likely 2 hp according to amp draw( learned that here) Have several of them. Good motors

 

[AGCB97]

I converted mine to 3 phase to make metric threading easy. I'm thoroughly satisfied.
Aaron

 

[Ironman2]

Been there, done that.
I took a 2hp single phase off, which was often pulling 25 amps(5hp equivalent) and put on a 5 hp 3 phase. Now I can have a cut starting to chatter and tweak the speed down or up to get out of the resonant frequency range and keep cutting. And when I'm done and shut off, the lathe stops in about 3 seconds because I set the braking to that. 1980 vintage lathes did not have auto brakes, now it does.

VFD's are disgustingly cheap now, 10 hp for under 200 bucks.

 

[Ironman2]

for $75 (said to be in excellent condition), and am now considering buying it and adding a VFD. I know just enough about this to make a bad decision and get into trouble. Both motors have the same size shaft, RPM, and HP. Is this a bad idea? Note the difference in HP - is this an issue? Here are the photos of the ID plates.

When You get your VFD it will have wiring instructions, and install and programming info. You will need to bypass your start switch and use the 24 volt bus to turn the 3 phase on and off, Do Not switch the 3 phase on and off with the original switch, or you will be sorry. The bypassed on off switch that was the original can be used to switch the 24vac from the control bus. In general, 3 ph stuff is about 10 bucks a hp, cheaper than single phase. I have yet to buy a 3phase motor, people give them to me for scrap. I have a 40 hp motor sitting in my yard right now.