Rotary Phase Converter Question for Newbie

[Eddyde]

I built my 7.5hp RPC to run my 5hp lathe (here) and have similar balance under load. I think AB 236 AC 238 BC 242 is excellent.

 

[Groove]

I know this is an older thread but my question seems appropriate for this thread.
question: I would like to build a RPC and I was wondering if I need a special type of 3 phase motor to use as my power source Idler motor? Or if I can buy any 3 phase motor for my idler?

 

[rabler]

I know this is an older thread but my question seems appropriate for this thread.
question: I would like to build a RPC and I was wondering if I need a special type of 3 phase motor to use as my power source Idler motor? Or if I can buy any 3 phase motor for my idler?

Pretty much any standard 3 phase induction motor will work. (Obviously you want one that can be wired to your desired voltage, typically 230VAC). Generally folks prefer the lower rpm motors as they are usually a bit quieter. Typically a used (i.e., ebay, etc) motor makes a good candidate, as the idler motor doesn't see a lot of torque it isn't going to stress the bearings like actual drive use.

 

[benmychree]

I used a 7 1/2 HP 1750 RPM 230 V motor for the one that I built, and used a static phase converter to start it, and added oil filled capacitors to (ar least attempt to balance the manufactured leg, noisy, but it works.

 

[Groove]

Pretty much any standard 3 phase induction motor will work.

So not being an electrical guy understanding the terms, I am not sure if an "induction motor" is different than any other off the shelf 3 phase motor. Thanks for the reply Rabler

 

[Groove]

Never mind Rabler: I found this in Wikipedia: An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.
- Im not used to electric motors generating power (to create the third leg) as they usually drain power but again my Electrical Knowledge is not worth talking about.

 

[Eddyde]

Yeah, pretty much any 3 phase motor will be an induction motor and work for a RPC. There may be some brushed 3 phase motors out there but I've never heard of or seen one. The good news is used 3 phase motors are usually pretty cheap as commercial and industrial users are just going to buy new. I paid $100 for a used 7.5 hp in great condition off of FB Marketplace.

Here is a link to my RPC build:

Rotary Phase Converter Rebuild / Build

Hi all, I just hooked up a used, Snyder brand, Rotary Phase Converter to my newly acquired lathe (more on that soon). It works but makes excessive noise & vibration, especially when running under no load condition. It sounds like its vibrating at 60hz so my thought is its electrical in nature...

www.hobby-machinist.com

Please feel free to reach out to me if you have any questions.