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How to convert 220 3ph to 440 3 ph?

Jack Cadwell

Plastic
Joined
Aug 28, 2009
Location
Warwick, Massachusetts
I might buy a machine with a 10 hp 440 3 phase motor. Right now, all my three phase stuff runs off a 20 horse power rotary phase converter. The legs are not balanced, but they run everything. I would like to set up a transformer of some sort that will convert 220 to 440.

Has anyone done this?
 
I might buy a machine with a 10 hp 440 3 phase motor.
First look at the motor to see if you can reconnect it. Many, if not most, you can. Problem solved, with only about an hour of fiddling time and a new set of heaters on the contactor.

If you can't, and don't want to rewind the motor, then it's simple, three single-phase step-up transformers. But that's probably more expensive than rewinding the motor and you don't really want 440v around the house if you can help it.
 
First look at the motor to see if you can reconnect it. Many, if not most, you can. Problem solved, with only about an hour of fiddling time and a new set of heaters on the contactor.

If you can't, and don't want to rewind the motor, then it's simple, three single-phase step-up transformers. But that's probably more expensive than rewinding the motor and you don't really want 440v around the house if you can help it.

I was expecting the motor to be dual voltage, like just about all the other motors I see. This one is from Italy on a good quality machine. The photo of the plate on the motor was pretty clear. Given that it has 440, it might go for less at auction, making the transformer worth it.

I will look at three phase step up transformers.
 
I might buy a machine with a 10 hp 440 3 phase motor. Right now, all my three phase stuff runs off a 20 horse power rotary phase converter. The legs are not balanced, but they run everything. I would like to set up a transformer of some sort that will convert 220 to 440.

Even if only the windings for 440v were brought out, a motor shop should be able to go in and tap the necessary windings to bring out leads for 220v connection. Might still be more convenient & cheaper than a transformer. Though you would have to up-grade all the heaters in all the original motor controllers, and maybe even the wiring in the boxes.

Has anyone done this?

Yes. Reported here in past years with photos and details. My wood shop has a 550v machine (Diehl lumber jointer). My metal shop in separate building has several 440 machines. At a glance, a transformer is pretty quick solution. In most cases it will be necessary to balance your converter or the mag starters probably won't function well. IIRC my low leg was some 60v down before balancing, at 550v. Had similar issues in metal shop since one machine has 4 starters/motors on it of widely varied HP.

You are probably aware, there are surplus electrical equipment dealers - we have a good more or less local one in Auburn, NY. Good, clean tested equipment for 1/2 to 1/3 new price. Of course if you are good at scrounging, less organized junk yards sometimes have equipment for about the going scrap price.

The write up i did here was on the Diehl lumber jointer set up. Hope the pix are still connected.
smt
 
@stephen thomas, there's also a good one at 217 Border City Road in Geneva, NY, M&M Electrical Surplus. Haven't bought there in a few years, but the prices were good back when..
 
I had a dual voltage system set up in my garage shop for many years. Had a 5 horse German Hurth mill, a 7 1/2hp G&E Shaper, and at times a 3hp? Boyer Schultz Surface Grinder all running off 440. I used a 7 1/2hp RFC to feed a 220VAC 3 phase breaker panel that had one breaker feeding a 220/440 3 phase transformer, This transformer was brought into circuit with a large contactor. That output fed a separate 440 breaker panel that in turn fed the machines.

As many have suggested, I got the transformer and breaker panels from a local surplus electric place. Just figure your potential 440 current needs and convert that to KVA,, which transformers are rated at.

I don't remember if this transformer was a step up or down or if I even knew enough to care at the time I got it. All I know is it said 220 on one side and 440 on the other. Whether I used it backwards from it's original intent is beyond me. I do know that when I moved into an industrial place and had to have an electrician wire it in, he had no squabbles other then having to dig into some correct grounding information. The transformer was about a 3 or 4 foot cube. Aluminum wound.

So in short... it's completely doable. Never had any problems... and it didn't kill me or shock the sh*t out of me.

Here is a picture of my electrical setup that happens to include the finest 40 taper knee mill you'll ever see. :-) On the wall behind it and to the right are the 440 panel up high and the smaller 220 down below. The tan box with the E-stop showing right under the boring feed control panel on the mill was the control panel for all of it. You can't see about 5 more buttons. I had the phase convertor and the transformer down the basement and operated remotely so I wouldn't have to listen to the damn things. (Transformer was not noisy) I used timing relays on the startup. Push and hold for 220, hold a little longer for 440. Of course both could be up and running at the same time. Sorry I couldn't find a picture of the transformer or name plate. They're gone now. I switched everything to 208 when the building changed from the old high leg system. Lost the power feed on the X because it was a 2 speed motor with brake that couldn't be reconfigured. I'm working on getting that back.
 

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I run a big German shaper with a transformer, 220 to 440. It has a 9hp 2 speed motor, plus a lower amperage starting mode. Rotary switch goes from start, to low speed, to high speed. Got a used transformer for a couple hundred bucks, installed a fused disconnect, works great with original controls. Bit of a hum in the transformer, no big deal. I do have industrial 3 phase, no idea if the RPC complicates things.
 
Thank you, everyone.
I'm going to hire a friend who is an electrician, and try buying second hand stuff. It sounds like it is possible to run the new motor on my system, with some add ons.
 
@stephen thomas, there's also a good one at 217 Border City Road in Geneva, NY, M&M Electrical Surplus. Haven't bought there in a few years, but the prices were good back when..

I'll second M&M. Was up there about a year and a half ago scrounging up a 3 phase motor. They have a ton of stuff, wish I had known of it earlier. Good people to deal with from my perspective.

Dale
 
@stephen thomas, there's also a good one at 217 Border City Road in Geneva, NY, M&M Electrical Surplus. Haven't bought there in a few years, but the prices were good back when..

Whoo boy, i can be a font of mis-directions sometimes:o

M & M is exactly who i was thinking of.
I've made several trips up there over the decades, but obviously so infrequent as to have to look them up when necessary.
I just know from Elmira, you kind of head generally north between 2 big lakes. Lots to choose from....:D

smt
 








 
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