converting 3 phase to single phase ?

Keith Molden · Oct 15, 2017

I bought a pedestal grinder with 12" grinding wheels at an auction yesterday. It was one in the welding shop at the high school & works great. The only problem is that most folks in this area do not have 3 phase so I'm wondering if it can be changed to single phase by changing some wires around. I have a 3 phase converter but I don't need it and can sell it a lot easier if it is converted. Electricity is something I know very little about. Keith

DeltaRed · Oct 15, 2017

I know about as little as you. 3phase is 440V.Single phase is 220 or 110. I was told once that single phase would run on 3 phase power.However the extra voltage would be an issue.Most of this is probably not true.I really don't know.....Someone will straighten me out.Of that I am sure......LOL However,most electric motors have a chart inside to show how to wire for different voltages.Again, don't go by what I'm saying. It's probably all wrong.Let the experts tell you the right,safe way.

tim s · Oct 15, 2017

No you can't convert it...3 phase power is great to have,a lot of heavy duty equipment can be bought cheap if it's 3 phase. I have 3 phase power direct from the power line here at my shop, and I am fortunate to have it. At my Home farm where we really need it we don't have it,,so a big converter is needed.

coonie minnie · Oct 15, 2017

There is 220 3 phase... I have it here. There is also 208. But no, you cannot convert the grinder.

Keith Molden · Oct 15, 2017

Thanks guys for the responses. I guess I'll sell it as 3 phase then

dr sportster · Oct 15, 2017

I thought you were saying you had 3 phase service and a 220 volt motor. Which would work but a 3 ph motor on your service will not.

Greg K · Oct 15, 2017

Or you can buy a variable frequency drive that uses single phase and makes a fake 3 phase. This would allow you to control the speed and give you the 3 phase you need. Not all frequency drives will do this so make sure to compare. What size of motor does the grinder have?

tim s · Oct 15, 2017

Wish you were closer,,Darn it..

kcm.MN · Oct 15, 2017

Don't know what hp the motor on the grinder is, but if your existing phase converter is rated to handle that hp, you could always advertise the two together with the notation, "Can sell separately". Just make sure to not give the converter away by pricing it too low in a package deal.

buickanddeere · Oct 15, 2017

Order a VFD from eBay and make the three phase power.

Keith Molden · Oct 15, 2017

I've got a 3 phase converter to run my South Bend lathe but I have a good 110 volt one that does what I need. Bought this one to sell.

Texasmark1 · Oct 15, 2017

3 phases develop their own motor torque due to the 120 degree difference in the phases. In an induction motor you need something to give you some torque, a split phase or capacitor start/run function. I am not a motor guy but I'd suspect besides the voltage being higher 230 single vs 208 3 ph, you'd have to spin it manually to get it to start and run if it would do that.

jacks · Oct 15, 2017

What Buickanddeere said. Buy a V F D for 100-150 on Amazon or eBay. It might be hard to find a buyer for it as is without a speed drive. A 3 Hp motor equates to 2.2 k w so I believe it would draw something like 18 amps running which is too much for a 20 amp 120 volt circuit to power a V F D. You should buy a 3 h p V F D which accepts a 240 volt single phase input and provides 3 phase output at whatever voltage your motor is rated for. Set up this way with variable speed control it will be a very useful unit and will be attractive for use in small farm and business shops.

Dave Sherburne, NY · Oct 16, 2017

Where is it???

Keith Molden · Oct 16, 2017

I think I might have mislead you guys on the one I have. I have a pedestal grinder that is 110. The 3 phase converter I have is a 5 hp. converter to operate the South Bend lathe. I don't need the 3 phase grinder so I think I'll sell it but I'm not going to buy a converter to operate it with just to sell it. The new owner can do that if they want.

converting 3 phase to single phase ?

Keith Molden

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DeltaRed

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tim s

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coonie minnie

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Keith Molden

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dr sportster

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Greg K

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tim s

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kcm.MN

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buickanddeere

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Keith Molden

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Texasmark1

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jacks

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Dave Sherburne, NY

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Keith Molden

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