# Switch from 3 phase to Single Phase Saw Motor



## TurbineTester (Jun 4, 2010)

I got a steal of a deal on a refurbed 5HP 3ph PM66 a while back. I don't have 3ph power and I haven't been able to get my hands on a good deal on a VFD or rotary phase converter so i was thinking of just getting a Single Phase 5HP motor and using it instead of the three phase motor. I'll just hang on to the 3 phase motor for now. Where would you go to get a 5HP single phase motor for this saw? Would you buy a used one or a new one? Best source for new and used? thanks!


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## crank49 (Apr 7, 2010)

http://www.grizzly.com/products/Motor-5-HP-Single-Phase-3450-RPM-TEFC-220V/H5390

This is a link to Grizzly. Advertized price of $369.

I don't know your location so of course freight might eat you up, but it's a number to start with.

Around here, Tennessee, I'd go to a Tractor Supply or Co-Op as most farm supply stores have motors in stock.

Graingers or Northern Tool are more sources.

Of course for used it would be prudent to check Craigs List.


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## BillWhite (Jul 23, 2007)

Not an electrician here. I didn't know that you could power a 5 hp motor (real 5hp) on single phase. Why not check with an electric motor shop. Might even be able to work out a swap of some sort.
Bill


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## oldworld124 (Mar 2, 2008)

I had a 5 hp single phase powermatic saw and I assure you it will be no problem running on a 220 volt single phase circuit providing you have the necessary amount of available power in your shop.

You will also need to replace the switch. These motors are not chap and will most likely cost around $500 when done. Not including running the 220 receptacle.

A good high quality phase converter seems runs about $2,000 to $2,500.


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## crank49 (Apr 7, 2010)

Baldor makes single phase motors from 1/12 up to 15 hp. Not sure about other manufacturers.

I might point out that a rotary phase converter has to have a single phase motor in it to run the 3 phase generator. And, since nothing is 100% efficient it would have to have a bigger single phase motor than the size of 3 phase motor it is capable of running.

A static converter uses capacitors to trick a 3 phase motor into running on single phase, but it will only have about 66% of its rated power.

A VFD is the best solution as it actually creates 3 phase power from rectified single phase.


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## TurbineTester (Jun 4, 2010)

I would love to have VFD. My Brother in Law works for an automation company, but because of the recent flooding and other issues in Japan, many of the manufacturers had supply issues the latter part of spring and into summer. Normally my BIL would have been able to get me a good deal on a VFD, but because of that there were none to be had for employee purchase. On top of that in order to run a 3 phase motor with a VFD you have to make sure that the motor wiring is rated for inverter duty. According to BALDOR the SAW DUTY rating is not synonymous with INVERTER DUTY and they do not recommend using this motor with a VFD. Most likely i would not have a problem, but for information's sake: there is it.

I have a 5HP single phase motor running my clear vue cyclone separator on 220V and i already have a 220v receptacle in my garage 2 feet from the service panel that i wired in preparation for this at the same time i ran the service wiring for the dust collector.

I actually have a 3HP rotary phase converter, but as you mentioned, it's not suitable for this saw. Electric motors draw maximum current on startup, and if you have an undersized phase converter you will get loud erratic rotation out fo the motor as it tries to vibrate it's way up to 3450 RPM. Correct me if i'm wrong, but the way a rotary phase converter works is by powering two legs of an oversized 3 phase motor with 2 220v single phase lines and capacitors, and then drawing the third leg of power back off the same motor using that third leg as a generator. So with the combinationof the 220v two line single phase current in your house typically used for your dryer/stove, plus the thrid leg off the rotary phase converter, you get three phases. But becuase of that setup you need to OVERSIZE the rotary phase converter by 50% of the motor you want to DRIVE. Or more simply, in order to run a 5HP 3ph motor you need a 7.5HP rotary phase converter.

I checked craigslist for electric motors in my area and there is nothing to be had right now. I have a 5HP BALDOR motor and a 3HP Rotary Phase converter i might be willing to trade for a 5HP single phase motor…anyone interested?  Any other suggestions?


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## TurbineTester (Jun 4, 2010)

Rick - Now that's something i guess i should take into account, just getting a 3HP. I think you are right in that i would be hard pressed to exceed the capacity of that with my infrequent use of my TS.


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## crank49 (Apr 7, 2010)

Rick, I stand corrected. I was thinking about a converter I installed on an induction melting furnace a few years ago. But that was the exact opposite. I had to have 500 KW of single phase for the furnace coil and used a MG set with a 3 phase motor running a single phase generator. But, the efficiency thing is still an issue. You can't get 100% of the energy out of any system that you put into it. There is always a loss.


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## cabmaker (Sep 16, 2010)

That saw is worthy of a real motor. Get a 5hp baldor and be done with it.(single phase of coarse)


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## Bill1225 (Oct 31, 2011)

i think the powermatic 66 has an odd mount so be careful when buying a motor i do know though baldor does make it


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## TurbineTester (Jun 4, 2010)

It's hard to justify spending $800+ when a perfectly suitable 5HP 1ph motor can be had brand new from BALDOR for about $400. Do you know of a good place to get a reliable inexpensive VFD?

Ooops well never mind it looks like that are closer to $500 from baldor…


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## TurbineTester (Jun 4, 2010)

Ok so here are some developments in this search. The original BALDOR motor is a 184C frame made specifically by a sub contractor of BALDOR for Powermatic for the PM66 line of TS. The current replacement part from PM are as follows
5HP 1Ph is 6472335 - ~$750
3HP 1Ph is 6472028 - ~$650

First things first, that price is absolutely ridiculous and they must be making about an 80% profit margin on those motors.

According to PM the replacement motor is a 145TC frame. They say it's a special motor, but they can't give me the dimensions on the motor face bolt pattern to show that it is actually diffferent from the standard 145TC mounting dimensions.

Here is a NEMA frame chart for anyone who is interested…

http://www.electricmotorwarehouse.com/PDF/NEMA.pdf

Just so everyone knows, you can get a 5HP 1Ph, 230V, 145TC, Leeson motor NIB from Electric Motor Warehouse for $350 plus shipping.

http://www.electricmotorwarehouse.com/120554.htm

Has anyone swapped a 5HP 3Ph for a 5HP 1Ph motor in one of these saws?
What did you have to deal with regarding the dimensions for the face frame mounting holes on the motor vs. the saw?
Are they the same?


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## chuckman (Feb 16, 2014)

Turbine Tester:
I have the same predicament only with a PM2000. What did you end up doing (phase convertor or new motor) ?


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## shawnmasterson (Jan 24, 2013)

IMHO I would just go with a static converter. You only be running at 2/3 power, but 5hp at 2/3 power is still plenty. I went the route of a rotary, because it is an investment that will allow for more equipment in the future.
Here it what I did. I highly recomend phase-craft. The owner/operator is very honest and knowledgeable.


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## Loren (May 30, 2008)

+1 on Phase-craft. There are two minor annoyances with
rotary conversion:

1. The idler makes a sound. It's not very loud but it bothers
me anyway. I put my idler outside so even if it's just a minor
hum inside the shop. Of course I had to plan to put it 
outside so I used a longer conduit than I otherwise would
have used to connect the idler to the panel.

2. You may have to run some heavier gauge wiring to the
phase converter panel and you'll need a dedicated breaker.

You can run a 3hp table saw motor easily with a 5hp rotary 
converter. That size converter requires a 30amp 220v circuit.


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## longgone (May 5, 2009)

Try some blogs, Craigslist or other woodworking websites to see if anyone with a 1 phase motor wants to trade for a 5hp three phase…there just might be someone out there wanting to upgrade in motor size.


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## SCOTSMAN (Aug 1, 2008)

I don't know about USA but ebay have very good deals on vfd's convertors here in the UK. I have two 5 hp at the moment but run about half of that on my one wood lathe , and metal milling machine. Where I get full speed control also. Alistair


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## chuckman (Feb 16, 2014)

Thanks for the quick replies. I've pretty much decided on a static converter. For about $100-200 it should yield about 3 1/3 HP which should be plenty for my workshop. Worst case scenario the motor eventually fails and I'll have to buy a 1phase motor after all.


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## Targa (Aug 21, 2013)

In the past, I've built a couple of rotary phase converters to power some 3 phase automotive machining equipment and one thing I found was that used 3 phase motors are very cheap. Perhaps as inexpensive as $10 per horsepower. You will be very lucky to find someone willing to trade a single phase 5 HP motor for a 5 HP 3 phase one. I think you are better off either buying a 3 HP single phase motor or building a rotary phase converter which you can probably build for under $200. I found my 3 phase motors at a industrial equipment dealer that sells large compressors, pumps and other equipment. They were brand new motors taken off of new equipment that the buyers wanted to upgrade the motors on either for something larger or a different brand.


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## Grandpa (Jan 28, 2011)

I decided on the static phase converter for my Unisaw because of the price and the recommendation from some friends. They tell me they run motors in the oil field for 15 years and they still have life. I figured if I got any life out of it then it was okay. Then if I had to buy a motor I would get it. I looked at some converters on eBay that were manufactured by Phase-Craft. When Christmas came along I got an email saying these were sales on items I had looked at in the past. I bought a 5 HP converter for $45. I thought that was a decent price and I might as well own it.


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## bobburk (Jan 7, 2012)

TurbineTester-
Just a quick FYI, it your still looking at VFD's give factorymation.com a look. From what I see on their site your looking to spend between $175-$225 for a VFD that would power your saw. As for their supply stock I can not say. I have one of their's running my 3hp Uni and is works great.
Bob


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## REO (Sep 20, 2012)

for compressors and the LOADED start up you need to oversize the RPC for a saw it will run just fine on something rated for 1/2 the HP of the saw. the rpc doesn't need an idler motor to get it up to speed! It can be started with a cap bank and a pushbutton start switch.


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