# 220 single phase to 480 3 phase?



## invisabledog

*220 single phase to 440 3 phase?*

Found an awsome deal on a pedestal grinder.  Problem is it's 480 3 phase, so the owner thinks.  I haven't seen it yet.  Can this be made to run from 220 single phase with the right transformers and or convertors?  I'm hoping when I see it, the data plate is there and I'm lucky enough that it may be a dual voltage machine.


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## mzayd3

Most every medium voltage three phase motor is dual voltage.  You should be able to rewire the motor leads for 240 volt and get a phase converter or vfd.  If it is 480 only, this would be a deal breaker for me as the required hardware would be prohibitively expensive.  


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## invisabledog

Turns out its 440 not 480, but it's not 220/440.  I did buy it, it was a good deal.  Basically paid scrap price for it.


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## John Hasler

invisabledog said:


> Turns out its 440 not 480, but it's not 220/440.  I did buy it, it was a good deal.  Basically paid scrap price for it.



Take it to a motor shop and get an estimate for rewinding it.


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## Eddyde

I don't think it wise to put the transformer between the VFD and the motor, so you would need a 220v primary 440v secondary, single phase transformer, and a single to three phase 440v VFD. If you are diligent on eBay you may be able to get said items for a reasonable price.


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## invisabledog

Eddyde said:


> I don't think it wise to put the transformer between the VFD and the motor, so you would need a 220v primary 440v secondary, single phase transformer, and a single to three phase 440v VFD. If you are diligent on eBay you may be able to get said items for a reasonable price.



That's what I was thinking.  Not being much of an electrition, I need to figure out what exactly I need for a transformer.


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## PJRitz

First use a transformer to step up the 220 to 440, you can size it based on the motor's horsepower, 1 HP =746 watts, so add a little safety factor and figure 1kva of transformer per 1 HP of motor and you will be fine.

Other note here, there is no difference between a step up transformer and a step down transformer, you just need a transformer with a 220v (or 240v) winding and a 440v (or 460v or 480v) winding

Next comes the drive, there aren't any 480v single phase input drives, so don't bother looking for them, however most (most meaning that there are a few drives that you cannot disable the phase loss detection that won't work) 480v 3 phase input drives will run fine on single phase for what you are doing, but you must oversize the drive by about double so that the rectifier section in the drive will be heavy enough to carry the motors current on just one phase, so buy a drive that is rated for twice the horsepower of what the motor actually is.


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## invisabledog

PJRitz said:


> First use a transformer to step up the 220 to 440, you can size it based on the motor's horsepower, 1 HP =746 watts, so add a little safety factor and figure 1kva of transformer per 1 HP of motor and you will be fine.
> 
> Other note here, there is no difference between a step up transformer and a step down transformer, you just need a transformer with a 220v (or 240v) winding and a 440v (or 460v or 480v) winding
> 
> Next comes the drive, there aren't any 480v single phase input drives, so don't bother looking for them, however most (most meaning that there are a few drives that you cannot disable the phase loss detection that won't work) 480v 3 phase input drives will run fine on single phase for what you are doing, but you must oversize the drive by about double so that the rectifier section in the drive will be heavy enough to carry the motors current on just one phase, so buy a drive that is rated for twice the horsepower of what the motor actually is.



So for a 2hp 440v motor, I need a 2kva 220 to 440 transformer and a 4hp drive?


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## Ulma Doctor

my 2 cents,

don't waste the time, money or energy trying to step up your voltage.
replace the 440 motor with a 230v motor.
(like this)http://www.ebay.com/itm/2-HP-ELECTR...585?pt=LH_DefaultDomain_0&hash=item3f3abebdb9

if you find a 230v 2 hp single phase motor, your problems will be small.

if you try to go the hard way you'll wrap up a lot of money quickly and you'll have lots of exterior circuitry

i can help you find a motor if you wish to go the single phase motor route.
let me know how i can assist, i'm glad to lend a hand.
mike)


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## Wireaddict

I agree with the majority here, look into replacing the motor, preferably with a single phase model, or with 240V or dual-voltage, 3 phase.  I bought a Sheldon lathe that ran on 480V, 3 phase, after I checked it out [& noticed that there was no info tag on the motor but _assumed_ that it was dual voltage].  After I brought it home & opened the motor pot head I discovered that there were only 3 leads!  The motor had an integral 4-speed gearbox so replacing it wasn't practical; I ended up buying an RPC & a used 6 KVA open-delta transformer.  I think these, plus a NEMA size 2 starter, push button switches, enclosure & shipping cost over $1K plus wire, sealtite, conduit, etc., needed to hook it all up.


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## invisabledog

Replacing the motor is an option, but I don't think it's that easy on this grinder.  I would like to restore this vintage grinder to it's original appearance.  To replace the motor and keep the original look would be almost imposssible, unless I found an original motor in the proper voltage.  I've found some 440/220/2kva transformers on ebay for $150 and less.  The vfd will be the pricey part.  I think, if I'm patient, I can score one for $200-300.  I like the challenge of the hunt for parts to make this old stuff work.  That being said, if anyone has a 220v Queen City 2hp motor laying around, cheap, hit me up.


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## Karl_T

I would not go the VFD route in this case.

Do you already have a rotary phase converter?

I have the rotary unit and bought a 440 only plasma cutter. Then picked up a three phase step up/down 220/440 transformer. Very common at industrial auctions. The plasma cutter works great.

Karl


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## invisabledog

Karl_T said:


> I would not go the VFD route in this case.
> 
> Do you already have a rotary phase converter?
> 
> I have the rotary unit and bought a 440 only plasma cutter. Then picked up a three phase step up/down 220/440 transformer. Very common at industrial auctions. The plasma cutter works great.
> 
> Karl



Unfortunately, no, I don't have a rpc.  Getting one is an option.  I should have gone that route when I got my mill.  I could get a rpc and be open to many more machine options in the future.  I wish I could build a rpc, but there are no sources here for parts to build one.  the 2 local scrap yards won't resell anything.  Not much indusrty left around here.  Nearest surplus or used parts sources are 100 miles.


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## Eddyde

I doubt the replacement motor route would work given the motor is the main body of the grinder. Having the motor rewound (as mentioned above) is a possibly that you should explore, especially as you are facing several hundred dollars in equipment anyway. If you do go the phase converter route, you can easily make a rotary phase converter from a three phase motor, there are many websites with instructions.


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## invisabledog

I've been doing some research online and ran across this.

http://www.alloyavenue.com/vb/showthread.php?7711-440v-to-220v-Can-it-be-done




The guy had a straight 440v 3ph motor that was wired in the star configuraton.  He cut the joined wires and rewired to delta, to run on 220v 3ph through a vfd.  He said it worked, the procedure generated much discussion.  Anyone else ever try this?  Would it work if my motor is wired in the star configuration?


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## Leitmotif

invisabledog said:


> I've been doing some research online and ran across this.
> 
> http://www.alloyavenue.com/vb/showthread.php?7711-440v-to-220v-Can-it-be-done
> 
> 
> 
> 
> The guy had a straight 440v 3ph motor that was wired in the star configuraton.  He cut the joined wires and rewired to delta, to run on 220v 3ph through a vfd.  He said it worked, the procedure generated much discussion.  Anyone else ever try this?  Would it work if my motor is wired in the star configuration?



That is a common practice with European motors and with some US made motors.  They will have six leads brought out of the windings.  IF your motor has only 3 leads out then a motor shop could go in and find the star point disconnect and reconnect for delta.  You will have to be careful to ensure the new connection will not have too much current in the windings otherwise you are in for a rewind - ALSO you should try to stay within + /- 10% on each winding voltage.  Check with an industrial motor shop and see what they think and reccomend.

IF nine lead you have a motor reconnectable ie dual voltage
IF 12 leads you can almost do anything you want wye start delta run or just wye or delta and dual voltage.

The RPC and a stepup transformer just may be a good option.  The other option is double HP rated VFD and run on single phase 480.

Dan Bentler


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## invisabledog

Took the windings to the motor shop.  He said he "might" be able to  locate and pull the star.  He indicated that on that old of a motor  being straight 440, it could have some other setup.  I didn't quit  follow what he said.  He wasn't happy with the old cloth covered  windings and made no garantee of success.  He also said there was no  garantee how long it would last in service.  It showed signs of having  been worked on before and the repairs were very brittle.  It came down  to, I could give him a bunch of money and it might work.  I could also  give him a bunch more money and get it rewound to 220.  I opted for a  rewind.  It's going to cost about $500, but will be safer and be set up  to run on the power I can provide, 220 3ph thru a vfd.  Also figure if I  have to sell it, it will be more desirable as a 220v unit and I can  probably recover all my cost.  I got it very cheap. The cost was about the same as a converter and transformer setup.   Now to get busy on  the restoration of the rest of it before the windings come back from the  shop.


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## Karl_T

I've never been sorry when i decided to do a job right the first time.

Karl


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## invisabledog

Karl_T said:


> I've never been sorry when i decided to do a job right the first time.
> 
> Karl



I'm the same way.  Rather be right and safe than sorry.


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## Micke S

invisabledog said:


> I've been doing some research online and ran across this.
> 
> http://www.alloyavenue.com/vb/showthread.php?7711-440v-to-220v-Can-it-be-done
> 
> 
> 
> 
> The guy had a straight 440v 3ph motor that was wired in the star configuraton.  He cut the joined wires and rewired to delta, to run on 220v 3ph through a vfd.  He said it worked, the procedure generated much discussion.  Anyone else ever try this?  Would it work if my motor is wired in the star configuration?




If it is Y-wired for 440 V you can D-wire it for nominally 255 V. My guess is that it would then work fine on a 220 V 3-phase drive. You will not get full power but the difference shouldn't be too big, in the region of -20% derating.


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## Leitmotif

invisabledog said:


> Took the windings to the motor shop.  He said he "might" be able to  locate and pull the star.  He indicated that on that old of a motor  being straight 440, it could have some other setup.  I didn't quit  follow what he said.  He wasn't happy with the old cloth covered  windings and made no garantee of success.  He also said there was no  garantee how long it would last in service.  It showed signs of having  been worked on before and the repairs were very brittle.  It came down  to, I could give him a bunch of money and it might work.  I could also  give him a bunch more money and get it rewound to 220.  I opted for a  rewind.  It's going to cost about $500, but will be safer and be set up  to run on the power I can provide, 220 3ph thru a vfd.  Also figure if I  have to sell it, it will be more desirable as a 220v unit and I can  probably recover all my cost.  I got it very cheap. The cost was about the same as a converter and transformer setup.   Now to get busy on  the restoration of the rest of it before the windings come back from the  shop.



Recommend you find out the cost of rewinding for dual voltage.  ALSO have him bring out all 12 leads.

Dan Bentler


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## Luminast

And be sure to have him check out the bearings and get a cost to replace them.  If they are standard bearings, the cost will be small since he will already have it apart.  (Being that old, who knows?)  Then, unless the shaft is damaged, it should be as good as a new Baldor grinder.


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## invisabledog

Luminast said:


> And be sure to have him check out the bearings and get a cost to replace them.  If they are standard bearings, the cost will be small since he will already have it apart.  (Being that old, who knows?)  Then, unless the shaft is damaged, it should be as good as a new Baldor grinder.



I only gave the motor shop the windings.  The rest of the parts I have in the shop.  Already purchased the new bearings.  $20 for the pair, MRC nos.  Free shipping too )


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## British Steel

Leitmotif said:
			
		

> Recommend you find out the cost of rewinding for dual voltage.  ALSO have him bring out all 12 leads.
> 
> Dan Bentler



It won't have 12 leads, it's an English motor - 415v wired star, 240v delta, like almost all English / European (380/220v) motors. Some aren't rewirable for delta in place of star though, the motor in my lathe is 415v-only (3-speed, Dahlander wound for two of them, separate winding for the other) so I had to hack a 415v VFD to get the correct voltage from 240v single-phase...

The 415v motors made in England translate as 480v in the USA as they're pretty much V/Hz devices so require 480v at 60Hz compared to 400-ish at 50Hz, so applying 240v at 60Hz will cause a slight drop in power from the nameplate rating, otherwise they'll work just fine wired Delta.


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