Official Luthiers Forum!

I am looking at buying an old heavy piece of equipment (sander) and it is currently set up for 3-phase power. Typically speaking, can most moters be rewired to run on single phase? I really don't know anything about 3-phase power.

I know you can buy those converter systems, but that is more hassle than I want to deal with. If it is fairly straight forward (even if I have to find an electrician to do it) I may go for it, if not... I will let it pass.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

No a three phase motor will not run on single phase power. In most areas the utility will not provide three phase power to a residence, but it is available in commercial or industrial areas.
Your only options are replace the motor with a single phase one, or to use a phase converter to artificially deliver three phase power to the motor.
The phase converter is really not a bad option. They are small, affordable, and not difficult to install.
What is the voltage and horsepower of the motor? I need this info to give you more advise.

AlA Peebels38870.9301967593

Brock I just looked at Grizzley tools catalog, and they have static phase convertors from $150.00 to $230.00 depending on your horsepower requirement. If the voltage is correct, this would be a good way to go.

Al

Thanks guys.

Here are the specs on the motor.

1-3/4 HP
220 volt 3 phase
5.9 ampBrock Poling38870.9556828704

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I would recommend using a VFD (variable frequency drive). They will run a 230 VAC three phase motor on 230 VAC single phase. The advantage is you have variable speed and reversing capability along with soft start, braking etc. all programmable.vfd

If you plan on eventually running more 3 phase motors then the best option is a rotary phase convertor from brands such as Arco, Ronk and others.

Static phase convertors are good for a single machine but a rotary phase convertor can supply 3 phase for an entire shop.

VFD drives are very interesting...I run both AC and DC drive motors on 2 of my 3 lathes. I bought them for the variable speed control but they are a very interesting option.

I Knew that the prices were coming down for VFD's, but those are quite reasonable.

Al

I've been playing around with the VFD on my CNC, and now I want one on every machine in the shop. The 5 Bears guy has a tutorial on his web site about setting one up on your drill press. Interesting reading.

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John Watkins
CNC Guitar Parts

Not sure what motor prices are where you guys are, but for the price of the converter, you could get a whole new motor up here, save the space and wiring and have something new with warranty. I built a thickness sander for a student, and a 2hp/220v was 220 bucks.

Unless it was something like a 5hp I wouldnt bother with the converter. even then, the price for a new motor would be about the same.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Heh. I'm in a similar position, and I'm going to buy a regular phase converter (found a local place that does them for pretty cheap), maybe a VFD if it's very cheap. If I've got a good quality 3-phase motor, which will run better than a single phase, be cheaper to replace (second hand 3-phase motors are out there in droves), why not, right?

Still, gotta figure out the what and the how of the installation now...

I run a 415V 5HP 3-phase motor on my big 20" bandsaw and managed to buy a rotary converter at a bankruptcy sale very cheaply indeed, ?50. The grunt from a big 3-phase has to be experienced, I'm looking for a good 3-phase motor for my table saw now. If you can, stick with the 3-phase.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

it is very simple, even for an electrical ignoramus like me, to build your own phase converter, and there are several vendors selling the plans on ebay complete with directions for sizing the balancing capacitors.

i am puzzled by the variable drives though; if they are so much cheaper and will supposedly do so much more than a converter, how are the converter guys still in business? it seems that there has to be a limitation somewhere?

5 Bears
I believe this is the VFD retrofit that John mentions above.
For those wanting to convert an existing lathe, sander, drill, mill etc. from single speed motor with belt change to change rpm, a DC motor is an option. I'm thinking in terms of a permanent magnet type DC motor which is controlled by an SCR drive.
motor
This would be an example of the DC motor.
control
And the controller. This type of equipment can be found on Ebay also.