I am looking to replace the 5HP 3 phase motor in a M66 powermatic table saw with a single phase motor. Looking around on the web I've discovered these replacement motors are crazy expensive. Was wondering if anyone had a used one they would like to sell or someone who knows of a place to get a replacement motor that isn't soooooo expencive.
replacement motor M66 powermatic tablesaw
- Thread starter ninjasnail
- Start date
I've swapped out a many motors on the 66 saw. I've found the Leeson to be the best value over the years even with inflation. Its easy to pick up a three phase saw for cheap from the various school auction places. If you can get a 66 running to suit you for under $1500.00, you've done well. You've gotten a quality USA-made saw in service for quite a bit less than half price for what they would have sold for now. We all hope you can get it running for a few hundred bucks.
Besides the motor, there's the expense of a good starter capable of handling the higher amperage of a single phase motor. Shiny from China starters are good for the short term, but those tiny contacts starve the starting capacitor to early failure.
Besides the motor, there's the expense of a good starter capable of handling the higher amperage of a single phase motor. Shiny from China starters are good for the short term, but those tiny contacts starve the starting capacitor to early failure.
Look at the Connection to the attachment plate, See which configuration Powermatic calls for J56, 42c, ...etc.
Then measure (or look up) the diameter and length. Then you can get pretty much any motor that will fit. One thing to check is to see the duty cycle rating and the efficiency rating. Generally speaking, farm duty or hazard motors tend to be better due to the fully sealed case assembly. Beyond that, I replaced a motor on my lathe with a basic Chinese generic motor that was a compressor type motor, 3hp 85% eff. So, the motor was really giving me 2.55 hp of true work output. Likely, the original Powermatic motor is also a .85 eff so a 5 hp would be 4.25 of true power output.. ... I digress
Bottom line, the 3 hp motor was less than 200 bucks and 4 years later still going strong (sold that to a buddy). Pays to do your homework.
Then measure (or look up) the diameter and length. Then you can get pretty much any motor that will fit. One thing to check is to see the duty cycle rating and the efficiency rating. Generally speaking, farm duty or hazard motors tend to be better due to the fully sealed case assembly. Beyond that, I replaced a motor on my lathe with a basic Chinese generic motor that was a compressor type motor, 3hp 85% eff. So, the motor was really giving me 2.55 hp of true work output. Likely, the original Powermatic motor is also a .85 eff so a 5 hp would be 4.25 of true power output.. ... I digress
Bottom line, the 3 hp motor was less than 200 bucks and 4 years later still going strong (sold that to a buddy). Pays to do your homework.
That motor is a face mount type (aka: C-frame) A Baldor brand 3 HP motor shown below. On that saw a 3 HP motor is about all you'll need and it doesn't suck up so many amps that you have to have a special starter and heavier gauge feed wire.
I use a phase converter for machine tools but not for woodworking machines that I'm constantly turning on and off. There's also the hope that a VFD will be a cheap way to get a 3-phase motor working but it isn't so cheap and the hookup can be confusing to someone without digital electrical theory experience.
I use a phase converter for machine tools but not for woodworking machines that I'm constantly turning on and off. There's also the hope that a VFD will be a cheap way to get a 3-phase motor working but it isn't so cheap and the hookup can be confusing to someone without digital electrical theory experience.
Thank you very much for all this information.
One follow up question. I've run across a video talking about replacing the 3 phase motor with a single phase on this machine.
The video states that the switch needs to be replaced during this conversion (go time 1:54 in this video
). Do you know if this is true?
One follow up question. I've run across a video talking about replacing the 3 phase motor with a single phase on this machine.
The video states that the switch needs to be replaced during this conversion (go time 1:54 in this video
That's a pretty good video within the limits of that guy's experience.
He's showing a later model with a Chinese IEC switch. I hate those things. They have flimsy contacts.
What switch is on your existing saw? He does show a re-wiring protocol that will work and if you're putting in a 3 HP motor, it is likely heavy enough.
One rookie mistake he makes is that he uses Romex wire. Electrons run around the perimeter of the wire. That's why all machinery will have stranded wire rather than solid copper wire. Better current flow. On startup, a single phase motor will draw three or more times the rated amps for just a moment or two until the motor is up to speed.
We don't have a photo so there's a lot we cannot assume. Powermatic made a lot of 66s over the decades. Motor and switch suppliers varied.
He's showing a later model with a Chinese IEC switch. I hate those things. They have flimsy contacts.
What switch is on your existing saw? He does show a re-wiring protocol that will work and if you're putting in a 3 HP motor, it is likely heavy enough.
One rookie mistake he makes is that he uses Romex wire. Electrons run around the perimeter of the wire. That's why all machinery will have stranded wire rather than solid copper wire. Better current flow. On startup, a single phase motor will draw three or more times the rated amps for just a moment or two until the motor is up to speed.
We don't have a photo so there's a lot we cannot assume. Powermatic made a lot of 66s over the decades. Motor and switch suppliers varied.
I'm picking up the saw this coming weekend. I'll have pictures then. Can't wait to get this thing going!!!
So, appreciate your help and very impressed with your knowledge...
So, appreciate your help and very impressed with your knowledge...
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I converted my Drill press to 3 phase with a VFD and converted one of my table saw to single phase. If you want single phase you will need to buy a 3hp rated switch (2500w min.) If the motor is older, the configuration and tech can be different so you need to check the switch will work. The newer motors not so much an issue.
Powertec and others like Shop Fox, Rockler are all similar with cost between 40-60 bucks +/-. My guess all these switches probably come from the same factory.
Electricity can be tricky, not as linear as a lot of ppl think. Do your homework and good you are asking questions
Powertec and others like Shop Fox, Rockler are all similar with cost between 40-60 bucks +/-. My guess all these switches probably come from the same factory.
Electricity can be tricky, not as linear as a lot of ppl think. Do your homework and good you are asking questions
Another error that guy makes is the assumption that wiring backwards will reverse the motor. He's changing to a single phase motor so that doesn't apply. Swapping feed leads to reverse works only on three phase motors. On a single phase motor, it doesn't matter which sets of leads the two incoming hot wires go to.
Bob - when you say you don’t use a phase converter for wwking machinery, are you using a rotary phase converter? What about a static converter here?
Could he get away with a 3hp VFD? (Big jump in price for a true 5HP VFD). I have that set up on my 5HP RAS (13A FLA 3 phase) and it works fine but it will never see sustained heavy loads e.g ripping operations.
-Mark
Could he get away with a 3hp VFD? (Big jump in price for a true 5HP VFD). I have that set up on my 5HP RAS (13A FLA 3 phase) and it works fine but it will never see sustained heavy loads e.g ripping operations.
-Mark
I use a rotary phase converter (Arco HD) for machine tools where instant reverse is often used.
I once had a static phase converter for an old mill I had. It worked but reversing was a ritual of risk. There was never a situation where the downrated HP was a real problem.
A VFD is great when speed needs to be adjusted frequently and precisely.
For woodworking machines, I prefer a single phase motor because the motor always runs at full speed and there are a lot of on-off actions during a work day in the shop.
I once had a static phase converter for an old mill I had. It worked but reversing was a ritual of risk. There was never a situation where the downrated HP was a real problem.
A VFD is great when speed needs to be adjusted frequently and precisely.
For woodworking machines, I prefer a single phase motor because the motor always runs at full speed and there are a lot of on-off actions during a work day in the shop.
That's a diamond in the rough. If it weren't for the six hour round trip, I'd be talking to that seller. The price of the saw is half what that motor would cost (assuming the motor works).
Lots of work there but the end result will be a $3000.00+ table saw equivalent.
Since it is a Unisaw mount, the motor would not fit a Powermatic 66.
Lots of work there but the end result will be a $3000.00+ table saw equivalent.
Since it is a Unisaw mount, the motor would not fit a Powermatic 66.
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