220 single phase to 480 3 phase?

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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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
 
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
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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.
 
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.
 
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?
 
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?
Click to expand...

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

Karl
 
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?
Click to expand...


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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