# 3 phase to single phase



## Mizer (Mar 11, 2010)

I have found a used 16 inch power-matic planer for what I consider to be a good price. The only drawback is, it has a 3 phase 5 hp motor on it. I am hoping that changing it over to a single phase motor will be pretty straight forward. Has any one made a change over like this before?


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## TexasTimbers (Oct 17, 2006)

I started out in that direction when I bought my first piece of 3Ø equipment, but soon realized how much cheaper 3Ø equipment was so I installed a 10HP rotary phase converter in my shop. If you can go that route it could be a big advantage for you. 

If not, call PM and ask them what size 1Ø motor you should use in its place, because the planer will not operate efficiently with the same HP rating 1Ø. So if it has a 3HP 3Ø for example and you replace it with a 3HP 1Ø it will have far less power. You'd probably need a 5HP 1Ø to get close to the same power and the motor will probably be larger than the 3Ø.

If you can't opt for the rotary converter right now you can always go for a static converter it will just have ~33% less power but you won't have to go through all the hullabaloo of a motor swap. You can also find plans to build your own static or rotary converter. Of course the best option would be a frequency drive but that's overkill for your needs. A rotary converter is much better than a static, but I would still opt for a static over motor swapping, and denying myself the future of buying more cheap 3Ø equipment.

Not exactly what you asked for but, whattya want for nothin' a rubber biscuit? :w00t:





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## Mizer (Mar 11, 2010)

TexasTimbers said:


> Not exactly what you asked for but, whattya want for nothin' a rubber biscuit?


I have never gone away thirsty after one of your replies TT:smile:

I will check into the phase convertor, I have a friend that is running his shop on one of them.


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## rrbrown (Feb 15, 2009)

I don't think either a single phase motor or the static converter will work. Mizer stated it has a 5hp 3 phase which would mean maybe a 7 hp single phase motor if you can find one. Then it would need a 50 - 60 Amp 220 circuit. _The static converter from what I could find is not meant for long time or heavy load use. I'm no expert on the 3 phase stuff but I did read up on it a little._

The cost of a good 7 hp motor and the new electrical circuit could be as much as the rotary phase converter.

a 7.5 hp single phase motor is $751.00 plus shipping

a 10 hp rotary phase converter is $697.00

I'd go with the rotary phase converter if it were me.


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## TexasTimbers (Oct 17, 2006)

rrbrown said:


> . . . Mizer stated it has a 5hp . . .


Yeah I missed that Rich. 







rrbrown said:


> . . . I'd go with the rotary phase converter if it were me.


Me too, I was just saying I'd go with a static converter before I'd choose the motor swap, and now as you point out the 3Ø is a 5HP I would definitely avoid the motor swap because a 7.5 HP 1Ø will be impossible to fund used and will cost an arm and another body part to buy new. 3Ø motors are easy to find and inexpensive so building a rotary converter from scratch is not a big deal. 



rrbrown said:


> I don't think either a single phase motor or the static converter will work . . . .


Either one will most certainly "work". But the static converter will not be as efficient as a rotary and will "work" harder to do the job. The 1Ø motor option would be too expensive as mentioned and will also probably call for some serious mods regarding the cradle/pulley ad infinitum to adapt it properly. Static converters are fine for moderate use. Most of the detractors of them have never owned one. I haven't either but have a buddy who had been using one for over 20 years to operate his band saw and he uses his band saw more than moderately. 


P.S. You can buy 1Ø 7.5HP motors much less than that - < $500 actually but they won't be Baldor. :no:



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## Mizer (Mar 11, 2010)

I got the planer home this afternoon although I am not sure how I am going to get it off the trailer. After doing a little research on it (model E-15, circa 1952) I found out it was offered in either a 5 hp 3 phase or a 5 hp single phase. I think the one I bought is the same model as my friends except his a single phase. I might see if he is willing to trade motors as ever-thing else in his shop is 3 phase, which he runs off a convertor.


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## TexasTimbers (Oct 17, 2006)

I bet it'll work out. _Ever-dawg has his day._  









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## the marlboro man (May 24, 2010)

That's why you got it so cheap. All my equipment is three phase . I moved to the country and had no three phase service. I had to buy a add a phase. Their is no way to change it to a single phase. Three phase means you have four legs of electricity. Single phase has three legs. Sorry but if you have the chance to go three phase it's the best. It cut my electricity bill in half. It will also last longer. Good luck happy hunting for a three phase converter. Ronk is what I bought it's not to loud but annoying enough to turn it off when I don't need it.


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## TexasTimbers (Oct 17, 2006)

Not trying to split hairs, but 3Ø systems do not have 4 current carrying conductors ("legs"). 3Ø systems that have a 4th wire, that wire serves as the neutral and allows the 3Ø system to be tapped between neutral and one leg to provide 1Ø power for 1Ø loads. Center-tapped Delta transformers have a "wild leg" which puts out ~208v and that tap cannot be used for the 1Ø system or it'll fry the windings in the 120v load. Wye transformers are symmetrical and any leg may be used to provide 1Ø power. 

With a 120v 1Ø system there is only one current carrying conductor, a neutral, and usually a ground. A 230v 1Ø system has two current carrying conductors and a ground. Newer 230V 1Ø appliances require a four wire arrangement, but still only two of the conductors are current carrying. 

I don't believe 2Ø is in use anywhere anymore. 







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## The Engineer (Mar 16, 2010)

Guys, 5hp is 5hp. The difference is a 3 phase motor will have 3 hot wires sharing the load so there will be lower amp draw on each wire compared to single phase which will have 2 hot wires for 240volts. A 3 phase motor will not work on single phase power without a converter; it will just buzz till it overheats and fries..
- A rotary converter is a single phase motor running a 3 phase alternator; hence single phase in, 3 phase out. The converter will have efficency losses. It may require a 7 1/2 hp (or bigger) converter to run a 5 hp motor.
- A static converter uses capacitors to simulate a fake 3rd phase out of single phase. I know it gets confusing but single phase 240 volt power has two hot lines operating 180 degrees out of phase with each other. When one is positive 120volts the other is negative 120volts. The difference between the two is 240volts potential. Three phase power has 3 hot lines operating 120 degrees out of phase with each other. The voltage in each line is the total potential, 240volts, divided by 1.77 (the square root of pi) = 135volts The static converter charges capacitors from the two hot lines of a single phase source and discharges the capacitors into a 3rd line. It is able to provide the three hot lines, but it can't completely correct the 180 degree versus 120 degree phase angle shift. The 3 phase motor will run on this, but with reduced efficiency.
- An AC drive is a solid state variable frenquency inverter. It takes single phase AC power and converts it to DC, then uses solid state devices (SCRs, transistors, or triacs) to convert the DC back into 3 phase AC. This is the most efficient and newest technology out there.


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## woody woodturner (Jul 9, 2010)

heres more info to confuse australia has 3 phase power 415 volts haha and 240 volts single phase normal power when you talk 5hp 3phase motor you are talking a real BIG motor :thumbsup::thumbsup:


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## woody woodturner (Jul 9, 2010)

oh theres 5 wires in our 3phase systems delta -.star- neutral -negative-earth or ground .From what i understand which is not a lot delta or star not sure which one brings the motor up to speed with no power and when its there the other cuts in and puts the power on
now your confused right:laughing::laughing:


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## TexasTimbers (Oct 17, 2006)

The Engineer said:


> Guys, 5hp is 5hp. The difference is a 3 phase motor will have 3 hot wires sharing the load so there will be lower amp draw on each wire compared to single phase which will have 2 hot wires for 240volts. A 3 phase motor will not work on single phase power without a converter; it will just buzz till it overheats and fries..
> - A rotary converter is a single phase motor running a 3 phase alternator; hence single phase in, 3 phase out. The converter will have efficency losses. It may require a 7 1/2 hp (or bigger) converter to run a 5 hp motor.
> - A static converter uses capacitors to simulate a fake 3rd phase out of single phase. I know it gets confusing but single phase 240 volt power has two hot lines operating 180 degrees out of phase with each other. When one is positive 120volts the other is negative 120volts. The difference between the two is 240volts potential. Three phase power has 3 hot lines operating 120 degrees out of phase with each other. The voltage in each line is the total potential, 240volts, divided by 1.77 (the square root of pi) = 135volts The static converter charges capacitors from the two hot lines of a single phase source and discharges the capacitors into a 3rd line. It is able to provide the three hot lines, but it can't completely correct the 180 degree versus 120 degree phase angle shift. The 3 phase motor will run on this, but with reduced efficiency.
> - An AC drive is a solid state variable frenquency inverter. It takes single phase AC power and converts it to DC, then uses solid state devices (SCRs, transistors, or triacs) to convert the DC back into 3 phase AC. This is the most efficient and newest technology out there.


Every forum needs a _House Engineer_. His job is to scan for anything technical in nature, even if not in his field of study and repeat what has already been said. The rehash must however be in as technical a jargon as possible so as to confuse even the previous posters, to the point where they question even the validity of their very existence. :laughing:

Just jerking your chain of course, but you must like it in the kitchen because by choosing that user name you know you're going to feel the heat. 







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## The Engineer (Mar 16, 2010)

*Heat in the kitchen?*

Of course, TT. Actually it took me so long to concoct that post it was all original info when I started and just a rehash by the time it got posted. :laughing:


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## TexasTimbers (Oct 17, 2006)

The Engineer said:


> . . . . took me so long to concoct that post it was all original info when I started and just a rehash by the time it got posted. :laughing:



I wouldn't know anything about that. :innocent: :whistling2:


:lol:





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## mwhals (Apr 13, 2010)

TexasTimbers said:


> Every forum needs a _House Engineer_. His job is to scan for anything technical in nature, even if not in his field of study and repeat what has already been said. The rehash must however be in as technical a jargon as possible so as to confuse even the previous posters, to the point where they question even the validity of their very existence. :laughing:
> 
> .


Does a Chemical Engineer count? If so, maybe I should be making reactors out of wood! :smile:


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