Rotary, Static or motor swap

[Thaine]

I bought a pair of SB lathes this weekend from Southwestern OK State University. One 9" A model and a Heavy 10. The 10 has a 3 phase motor and my home shop isn't set up for this. My question to those who have been there done that is what route should I go and the pros and cons. I understand rotarys are more $ and noisy. Static seems to cost as much as a new single phase motor so ?. I can do my own wiring so running 220 is not a problem and I assume a 220 single phase will be better than a 110. Is there any reason to buy a static converter vice the motor swap? Thanks in advance

[dnsbss]

I would buy a rotary phase converter.most surplus machinery is going to be 3 phase. I have 2 mills and 4 lathes only one lathe is single phase.If you have a 3 hp rotary phase converter you can run 3 3hp motors at the same time, also the phase converter must have a load on it while it is running.

[SGW]

I had a static phase converter on my milling machine for quite a while. It worked...mostly, but I could stall the motor without trying too hard. With a static converter, the motor puts out only about 60% of its rated power.

The simplest thing to do is swap the motor.

Or look into a variable-frequency drive (VFD) from a place like www.dealerselectric.com .

Or, if you feel ambitious, build a rotary phase converter. There are plans on the Internet -- I don't have a link handy, but maybe somebody else does. Basically, you get another 3-phase motor about 2X the size of the one you actually want to run and put what amounts to a static phase converter on it to get it to start, then take the power for the machine motor off the 3 terminals of the extra motor.

But the easiest thing to do is swap motors.


[This message has been edited by SGW (edited 11-03-2003).]

[J. Randall]

Thaine, over on Practical Machinist they have a section dedicated to rotary phase converters. I have printed off several plans from links there, but havn't built yet. My daughter lives at Weatherford and I am about 70 miles west. Are you located somewhere close? James

[Sprocket]

I got a single phase motor replacement for my Heavy 10. It was originally three phase, and I think 440V. The new motor was easy to install, and after some thinking, the drum switch wasn't too bad either. For $150.00 for a new motor, it seemed the way to go.

[Thaine]

James,
I am in Clovis, New Mexico. I bought the lathes off of an pair of auctions the University had on eBay. Home shop is single phase. I have looked on the practical machinist site and could make the rotary listed. I've worked electronics for 35+ yrs. I just am not real upto date on the electrical aspect as far as effeciency etc. I am learning fast though and EE101 is coming back.

[wierdscience]

sorry couldn't get the link to work


[This message has been edited by wierdscience (edited 11-04-2003).]

[hambone]

I have worked my 5 horse 3-phase lathe with a 150$ static convertor for quite a few years with no problem at all. easy to wire. But I have wanted or need ed extra power trom time to time. It might be wise or something to consider planning ahead for rotary. If you are pretyy sure your machine's are going to be placed where you want them to be for a while. place your machines where it is easy to hook up easy access. to hook your wiring. I bought and sold a 16' south bend, 3-phase moter. but I mounted a static converter on the machine. It really made it easier for me to seel the machine when it was ready to go.

[hambone]

I have worked my 5 horse 3-phase lathe with a 150$ static convertor for quite a few years with no problem at all. easy to wire. But I have wanted or need ed extra power trom time to time. It might be wise or something to consider planning ahead for rotary. If you are pretyy sure your machine's are going to be placed where you want them to be for a while. place your machines where it is easy to hook up easy access. to hook your wiring. I bought and sold a 16' south bend, 3-phase moter. but I mounted a static converter on the machine. It really made it easier for me to seel the machine when it was ready to go.

[jr45acp]

Just my $0.02 worth, but I went with a rotary converter and was quiet pleased. If you're looking to buy outright, I would recommend you check with Anderson Phase converters. No association, just a very satisfied customer. I believe they're in Higby, AZ. A search will pull them up straight away.

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John B