575 volt motor problem

[iboc44]

OK here is a question for the electric motor guru's out there. I bought a first Bridgeport clone mill last weekend and I'm trying to get it all set up now. I knew it had a 3 phase 575v motor on it when i got it but i figured I'd just swap it for a single phase one. Upon closer inspection, the shaft of the motor is pretty unique. It's a 2J2 head. So my question is, can the motor be rewired to a lower 3 phase voltage, ie 220v 3 phase so i can just run it with a vfd? The motor plate only says 575v. But there are 5 wires coming out of the motor into the connection box. Two wires are just capped off separately. Or will that be impossible/not cost effective? My other option is the cut the shaft off of the three phase motor and through some careful machining on the lathe, graft it onto a regular single phase motor. I've looked all over the place but can't really find and answer.

Thanks in advance

Mike Simpson

 

[A_Pmech]

Mike,

It sounds like you have a single voltage motor rather than a dual voltage motor. I would run the machine with a phase converter and transformer.

Switching to single-phase is a mistake in my opinion. You lose the ability to power tap.

 

[nehog]

Can you post an image of the spec plate on the motor? Perhaps someone will see something you are missing.

 

[alfredeneuman]

600 Volt power, which is what a 575V motor is designed for, is a common 3 phase voltage in Canada.
120/208 Volt 3 phase and 120/240 single phase are the lower standard voltages in Canada.

600 volt to the lower voltage transformers are readily available, and reasonably priced.

Hook one up in reverse, with the 600V on the (secondary) output and the 208 or 240.
on the (primary) input.
It will just as easily transform the voltage from lower to higher as vice versa, but may need to be upsized to higher load rating (kva rating)

 

[iboc44]

Ok i get what you guys are saying and i have read the fact about losing the instant reverse. I don't know how much power taping i will do, but it would be nice. Could you not convert to a single phase motor and just use the break to power tap when changing directions? Ultimately I know very little about step up/down transformers for mains power and don't even know where to get my hands on one. Or how much it would be in this case. Cost isn't the only factor here. I would like to get this mill running for as low of cost as possible (obviously) but i don't want to sacrifice usability for cheapness. I guess I want the best/most cost effective answer. I'm not against getting a transformer but then i still need a rpc or vfd too. I could probably get my hands on a lower voltage 56c 3 phase motor and a vfd for less then a transformer and phase converter of some sort. I'm not opposed to that option aswell. Or am i just trying to cheap out?

Thanks for the help so far

Mike

 

[iboc44]

I'll post the motor plate tomorrow night when i get back home.

 

[iboc44]

Here is the motor plate picture

 

[A_Pmech]

It's a single-voltage motor as you suspected.

 

[alfredeneuman]

Have you checked into having the motor rewound to the lower voltage?

 

[Norcal]

Since that motor is a cheap Asian model, have you looked into a replacement motor?

 

[iboc44]

I called around to a couple places. 300$ is the best price to rewind the original motor to a lower voltage, then i still need a vfd. I'm still weighing my options on this one. I'd really like to keep the mill three phase but it seems like all the optins are the most expensive way to go. I looked into used transformers and that seems to be the most expensive. 300-500$ for the transformer then i still need a vfd.

 

[Strouty]

Look for a used 3 phase motor that has the lower voltage, I find them all the time for $50 to $100 depending on brand and HP. Having the VFD will be nice, but you could also make a rotary phase converter since you have the variable speed head.

 

[G_P]

Its only a 2hp motor. Should be easy to find a lower voltage 3ph one cheap from somebody who switched to single phase.