BigWoody created the topic: Best replacement motor? Use a phase-converter?
I just bought a 1978 Unisaw on Ebay. Model 34-466
It has a 3-phase, 230 / 460 motor, currently wired for 460. I need a single-phase motor.
I got such a good price on the saw, I figure I can just buy a new motor and I'm still doing well.
I am also considering using a phase-converter. However, only a rotary converter really makes sense, as it will maintain full power, but I can get a new motor for about the same price. The old motor seems fine, but I would probably rebuild it just to be safe, so there's another expense. Plus, I believe it must be re-wired for 230 before I can use the converter. The big advantage of using a converter would be that I could then buy other 3-phase tools. however, I don't see that as much of a possibility. I am leaning strongly towards replacing the motor.
This all raises some important questions:
First of all, and most important:
Would you go with the phase converter instead, and possibly rewire the original motor? If so, why?
If I replace The Motor:
How good WERE the Unisaw 3 HP motors in 1978? If I were to buy a stock Delta motor today, are they better? Worse?
What makes / defines a good motor?
I have read that Delta now uses Marathon-brand motors. How do these compare to Baldor, Dayton, and Leeson? Which would you choose, and why?
I have seen some 3 HP 1-ph replacement motors rated at a max of 14 or 15 amps, and other rated at 12 amps. Can I assume that the higher-amp-drawing motor will have more torque?
Should I get a 5 hp instead? The price is almost the same. Other than the need for more expensive wiring, what are the possible downsides?
Do any 1-phase motors include overload protection? If not, I read that I will need a new "GPE" switch. Is a magnetic switch the same as a GPE?
If they are different, should I get a magnetic switch, ANYWAY?
My saw currently has a very nice "emergency-off" switch mounted on the left side. I would therefore prefer, if possible, to use the existing switches. Can O-L protection be added in-between the switches and the motor?
If I WERE to use the original switching, which obviously was rigged for the 3-ph motor, I assume I would just use half of the existing wiring, assuming the gauge is heavy enough Correct? -Or does needing a GPE kill that whole plan?
What are some good places to purchase?
Does anyone sell re-builds and/or take trade-ins? -I would hate to just toss a perfectly good 3 HP / 3 ph motor.
Sorry for the long post, but I bet some of you have been through this before. any and all opinions are most welcome and appreciated.
I will only answer a couple of your questions. First the size of the motor will depend on your intended use. If you cut heavy and long go with more amps, for more torque. Second, new motors and rewinds of recent origin are more capable than the old motor. But the best thing I can do for you is send you to Wolfe Machinery in Iowa. Their web site is
. Good Luck!
DaveInHouston replied the topic: Re: Best replacement motor? Use a phase-converter?
What did you decide to do on your Unisaw motor? I have exactly the same saw (model and year) with the same issue and am trying to decide what to do. The phase converter sounds interesting but I don't want to go down that road only to find I'm not happy with it. And of course changing the motor to single phase isn't cheap.