phase converter

n175h

My son loves making sawdust and is always looking for good buys on tools. He scours Craigslist, etc and finds incredible prices on used stationary tools that are 3 phase. For instance, he found a 52" double belt sander for $3000, when a 16" open ended single phase is around the same price. Well, he doesn't have 3 phase in his garage and keeps talking about getting a phase converter. I know nothing about them other than they cost a bunch.
http://www.phase-a-matic.com/PDF/RPL.pdf

Question is: should that be an option for him to explore? or should he just keep looking for a score on single phase equipment?

Missouri Bound

It depends. Does he have a large enough service to support these rather large tools? Phase adders work well, but not often used in other than industrial applications.

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n175h

100 amp sub panel to the garage. 200 amp main on the house.

Missouri Bound

A sander that size can be up to 25hp. The service may not be able to handle the startup surge.

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mpoulton

What are the power requirements of the sander? If it's 5HP or less, then a VFD with single phase input is probably best. That is still an option for 5-15HP or so, but it gets much harder. Rotary phase converters are functionally acceptable, but inefficient, huge, and annoying. You can make a rotary converter much cheaper than you can buy one. All you need is a large 3-phase motor, some capacitors and contactors, and optionally a small single phase motor to start up the big motor.

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ddawg16

As Mpoulton said....VFD.....

Or....replace the 3 ph motor with a single phase 240Vac motor.....in some cases, the motor will be cheaper than the VFD.

However, if you have more than one 3ph tool....the VFD is cheaper.

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n175h

I think he did say it was 25hp. Sounds like it's not doable with what he has available.

bobelectric

Let him speak for himself.

mpoulton

25HP is doable with a rotary converter, which you could build fairly easily with a 30HP 3-phase motor.

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I am a lawyer, but not your lawyer. And who cares anyways? We're here to talk construction. This is DIY advice, not legal advice.