View Full Version : 220V/1ph to 440V/3ph???

07-14-2008, 10:32 PM
The Ironworker I want to buy has this 440V/3ph motor. I only have 220/1ph.
Checked on Lenze VFD like I have on my mill but they don't do a transformer up with any VFD's So.. what do I have to do here?

doctor demo
07-14-2008, 10:47 PM
The Ironworker I want to buy has this 440V/3ph motor. I only have 220/1ph.
Checked on Lenze VFD like I have on my mill but they don't do a transformer up with any VFD's So.. what do I have to do here?
Russ, The simple solution would be to change the motor. I am surprised that motor isn't 220-440 volt.
The other thing you could do is a step up transformer 220volt to 440 volt then a 440v rotary phase converter, and wouldn't that solve a voltage problem on your high voltage mill?

07-14-2008, 10:59 PM

The cheapest fix would be a new/used single phase motor. The next best option would be to get a step up transformer and convert your 220 to 440 single phase. Then use a 440 volt VFD to create 3 phase 440 for the motor. A side benefit is the variable speed.
What horsepower are we talking about? The transformer will be spendy if the horsepower is very high.


07-14-2008, 10:59 PM
Steve...Geez... you know I just took a salesmans word. That motor could be a 220/440. Ya... my VN... that ones a 575V machine. I'm not worried about it. The motor from my Ohio will fit it and I'll change out the motor on the BP head.
If that IW motor isn't a dual voltage... it'd prolly be cheaper to change the motor alright.

07-14-2008, 11:38 PM
As said lots of 208-230/460/3ph motors are dual voltage getting within 10% is usually acceptable, a VFD will handle the rest if the hp isn't too high then they get expensive.

07-14-2008, 11:50 PM
Hmm.. I think it's a two hp motor. The 50 ton uses a 3 hp/3ph OR a 5hp/1ph.

07-15-2008, 12:33 AM

If it is only 2 Hp then a transformer and VFD are very reasonable. A 3 or 5 KVA transformer would work great and not break the bank. Check to see if it might be a dual voltage motor. Very common on machine tools.


07-15-2008, 03:12 AM
I have not seen a 440v VFD that will take in single phase. All of the ones I have seen are 3 phase in only.

But really, that motor should be switchable to 240. Then throw a VFD on it. They are getting really cheap now.

Quetico Bob
07-15-2008, 06:28 AM
Donít know how well a variable frequency drive would work on a motor running under heavy load most of the time. As mentioned, I think a rotary phase converter or single phase motor would be the best bet. The site has some good comparisons and things to watch for.
Cheers, Bob


07-15-2008, 07:31 AM

I got a VFD for just under 500.00 bucks here. It is awesome. After some programing i can do lots with it. I have a potentiameter and i can slow the mill right down. Great for taping. Set the mill in the slowest speed and then use the potentiometer to kick it all down to maybe 10% rotation. The control pannel, i had to build is just a SPDT and a potentiometer in a regular light switch box. 2 sets of 4 - #18 guage wires, running to the VFD. About 4 hours to wire it all up. Best 4 hours i ever spent!

The transformer method works but it is expensive. I would try and get another motor, and install a VFD. Check your motor. If it has 6 wires comming from the inside of the motor, then it most likely is a 440, 220 motor. You just have to rewire your motor. I would have to look at my pannel, to see which wires go where. Check your motor plate. Sometimes the diagram is on the inside of the wire cover.

Rob :)

07-15-2008, 07:55 AM
Rob.. I have a VFD on my Ohio. But it's 220V/1ph in...220V/3ph out.
Guess this one really isn't a big deal... the motor runs a damm hydraulic pump... not rocketysciency..
I never got a rountuit for the speed pot on my mill. The old motor I have..if i remember right it is the wrong type of motor to put one of them on.
Same for the VFD induced engine braking.... the old motor can't do that.

07-15-2008, 03:02 PM
I don't know that there is any value to varying the speed on a hydraulic pump motor...or even that its wise.

On the other hand, its been my experience that a used 480V VFD might be cheap to come by as they are used in industry a lot.

I would look for the easy solution first....try and see if it is a dual-voltage motor and will run at 220V in which case an RPC is an easy solution that will power this and other machines for you.

Good luck. They sure are a handy machine to have around in a fab. shop. For weld-up stuff, it beats watching the bandsaw work sometimes.


John Stevenson
07-15-2008, 03:40 PM
I have not seen a 440v VFD that will take in single phase. All of the ones I have seen are 3 phase in only.

They are available in the UK.
240 v single phase in , 440 3 phase out



07-15-2008, 08:51 PM
Well for some reason, i did not get it that this was for your new iron worker. Duh on me.

AS for the speed pot, i may be wrong, but they will work on any 3 ph motor. The motor is still getting 220v but the HZ are being changed from 60hz down to 5. I.E. at 5hz the motor is still getting its 220 3 phase, just the HZ are only switching 5 times every second, instead of 60 times a second. My electrician told me not to leave the minimum pot setting at 0. 3ph motors do not like that, so my VFD is set at 5hz at the lowest pot setting.

Which iron worker did you buy

Rich Carlstedt
07-15-2008, 10:48 PM
John, That is a neat post.
We have TECO's here in this Country, so that model should be available !
I have not seen that model
I have a TECO 1 HP unit, I think it was made by Westinghouse

I did a 11 KAV 220 transformer to 440- single phase,
and fed a Hitachi 440 volt 10 KVA VFD.
It worked fine on a 6.5 HP ( 6.8 KVA) 3 phase 440 V Lathe

When using a 3 phase VFD with single phase feed, you downsize the load
as you can see in the above example.
You only can feed one capacitor bank...but it works

07-15-2008, 11:20 PM
My $.02. I built a RPC several years ago for my Gorton Mill. The mill is 460 3p, only. It is a two speed motor, and I am told this is very common for 2 speed motors to be single voltage only.

My RPC consists of a 10Hp Reliance motor. A capacitor start and phase lag/advance circuit. And a Square D multi voltage tapped entrance transformer. The entrance transformer is a 27Kva model, and way to big for the application, but I got it dirt cheap. I wired the entrance transformer in reverse, as a boost xformer instead of buck, and I send the 3 phase from the RPC to the xformer. The transformer reliably puts out 460 +/- 10Vac all of the time, and never comes close to getting warm. The transformer also has taps for 575 Vac and 6xx (I think). I bought everything except my caps from industrial surplus, and spent less than $200. The Xformer alone is worth close to $10K and was brand new ;)

I run both of my mills at 460, simply because that is all the Gorton can take, and I found that 460 3p VFD's are dirt cheap in surplus, because they can't act as phase converters. Therefore, I got a 460 only drive for $75 and the CNC is now VFD speed control.

Another great benefit of all this stuff, is the city electrical inspector is afraid to touch anything metal in my shop, and is mystified as to what I am doing with giant motor and transformer :D

The whole point of the post, is if it comes down to it, you can put it together for a reasonable price and get 460 too. And BTW, the reliance motor makes literally almost no sound. I have forgotten and left the SOB running in my shop before. I can only guess that all the folks that claim RPCs are too noisy, are trying to use clapped out or junk motors...


07-16-2008, 12:04 AM
Well I should know for sure in a few days. I gotta get a couple things cleared up with the salesguy (as in more for me) and i'm buying the Scotchman 4014T turret Ironworker. I'll see what the motor is for sure when it arrives.
Too bad.. I have to drill another 180 holes tomorrow...Ironworker won;t be here in time.

07-16-2008, 12:13 AM
Hi All,

Just some basic info... I have NEVER seen a VFD that can't be run on single phase input, regardless of voltage, period. I know they may not be rated for this, but they will work. Now you will have to derate them as to not over stress the input diodes. Normally about 50% so a 10 Hp 3 phase drive will safely run a 5 Hp motor with single phase input. I realize there might be a drive out there that will not work but my money will take the bet anytime ;) .
Now OT but interesting... Use a VFD to drive a single phase output. Most people will say it can't be done but I can show you where it is being done on a daily basis... 480 volt 3 phase input, 50 Hp VFD driving a 25 Hp 480 volt SINGLE phase motor. The 25 HP motor is actually a magnetic vibrator unit that is used to compact sand in a lost foam foundry process. They use the VFD to start the shaking slowly, then ramp it up to finish the compaction. They set, pack and pour about 1 casting a minute in alumunium with this process.


07-16-2008, 02:28 AM
I have seen some VFD with phase protection. They will error out with single phase.

Cant remember which ones anymore. Havnt been in the market for a VFD in a long while.

07-16-2008, 11:19 AM
Hijacking, sorry


It is on soft-starts, but I haven't seen it on modern VFD's, it might be there on some. I have found that on some VFD's that create their own control power from the line input that you might have to try various input lines to get the single phase to power the control circuits. I have found both L1-L2 and L1-L3 depending on the manufacturer, you just have to try.


07-21-2008, 03:28 PM
I haven't tried it yet yet, but it should work. Make a RPC with a 3ph 5 hp motor
and connect the 240v to the center of the field windings, and 440v output to the end of the field winding (three times). This should act like a step up autotransformer. at 1/2 the HP.

Rich Carlstedt
07-21-2008, 10:48 PM
Yes, I was going to try that
It is supposed to work with a "Y" wound motor

I will know if it does in a few months

07-22-2008, 09:44 AM
Russ:- Has it occurred to you to phone BC Hydro and ask what they will charge to provide you with 440 3 phase? After all, you are a business, and, with luck, 3 phase power may even be at the end of your driveway! That way many of your voltage/phase problems will go away. You can be sure it wont be cheap, but reliable. Duffy

07-22-2008, 11:31 AM
A rotary phase converter is the answer....and for future use. Switch the motor over to 220V.

A single phase motor of equivalent quality to the three phase will be expensive and only solves the problem for this machine. For less than the price of a single phase motor a converter could be built.

Eventually the issue of three phase has to be dealt with. Rotary is the cheapest general solution. Transformers can be used on the rotary's output for the odd voltage machines. (there are fairly inexpensive ways to "build" three phase transformers from pairs of cheap single phase transformers).

A VFD would also be a solution, but there's no need for variable speed on this type machine, it probably has variable speed already through valving adjustments.