Advise Needed On Converting Bridgeport Mill From 575V to 220v Single Phase

Jimbo · 2006-09-12T21:14:04+00:00

My son has just purchased an old belt drive Bridgeport Mill with 575V 3 phase motor. We only have 220 single phase in our hobby shop and I have been told by a local rewinding shop that they can rewire the motor to run on 220V single phase for probably no more than $700.00 CDN. Another option would be to remove the original motor, sell it and adapt a new 220V single phase 1HP or 1 1/2HP reversing vertical mount motor to the machine. I have been told by a local electrician that my only other option would be to buy a 220V to 557V phase converter then a step up transformer but I'm pretty sure that would cost a lot more than we have to spend. My questions are, has anyone on this newsgroup converted a belt driven Bridgeport to 220V single phase? If so I would appreciate all the info I can get before we take delivery of this machine. I am also curious to know if the 3 phase motor on the machine is in much demand and what a fair price would be if I decide to sell it. You can respond to me on this newsgroup or E-mail me at jimbo Thanks in advance Jimbo

Sep 12, 2006 30 Replies

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Gunner 20 years ago

Correct. And there is a lever allowing the solenoid to be manually pulled out of braking position and locked there. So one would assume that in that position..the heat builds up as long as the lathe is powered up and over the years....

This brake unit is intergral to the motor, in an elongated sheet metal end cap, not like the brakes mounted to the motor plates on regular Hardinge machines and snubbing against the motor drive pulley.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

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slats 11 years ago

USA cheapest best way yo go

scrap 3 phase motor install 2 phase (220) motor made in USA. Cheapest and best way to go

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Garrett Fulton 11 years ago

Ned, I understand about the 1/6 power loss due to running the 575V motor off 480V , but why tell the VFD it's a 50 cps. motor? I thought Canada was the same as the US, 60 cps. line voltage?

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Lloyd E. Sponenburgh 11 years ago

Garrett Fulton fired this volley in news: snipped-for-privacy@googlegroups.com:

I personally think it's a fool's errand. Those motors - in that form- factor, are available new and rebuilt in 230V ratings. They're not all that costly.

Lloyd

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Ned Simmons 11 years ago

That thread's old enough that I don't remember writing that, but I can explain it. Simple open loop VFDs are often called volts/Hz drives because they adjust their output to maintain the voltage to frequency ratio constant as the frequency changes, which in turn keeps the motor current more or less constant. So if you tell the drive the motor's nameplate says 480V / 50Hz, the drive will output 480V at 50Hz, instead of the default (in the US) 480V at 60Hz.

480/50 = 575/60

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Garrett Fulton 11 years ago

Okay. I understand. Thanks for the time.

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Lloyd E. Sponenburgh 11 years ago

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

Put a decent 3-phase inverter duty motor on there, and you can use the VFD for what it was intended to do!

F**K step-pulleys!

Lloyd

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F. George McDuffee 11 years ago

================ Fleabay has several listed. free freight ~400$US. (three phase)

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also see

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In a hobby shop you most likely won't need full power so for cheap see

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but see

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I have dealt with this company and found them to be good.

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Lloyd E. Sponenburgh 11 years ago

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

I have not seen any over about 3/4HP that will go 110 1-ph to 230 3-ph. But there are plenty of them up to 3hp, and a few up to 5hp that will do

230 1-ph to 230 3-ph.

You can also usually get away with derating larger 3-phase input ones by

1/3 when handline single-phase input... but not all brands, so be careful on that.

LLoyd

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Bob Engelhardt 11 years ago

I got a good deal on one like that a number of years ago. I thought it was a good deal until it arrived and I found that it needed a separate programming module! The modules were rare and expensive, but I got one, cheap.

The linked VFD might be programmable with a PC, or it might need a module.

Bob

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