Building A 5hp Rotary Phase Converter
I needed something to power that Bridgeport so I've been searching for parts for a long time to build this converter. This really is a simple project and can be done by anyone with a bit of competence in electrical wiring. It comes second nature to me being I work in the electronics and RF microwave industry. The bottom line here is if you feel doubtfull, seek the help of someone knowledgable in electrical wiring before you get hurt. I take no resposibility for someone's careless mistakes. In short, electricity kills - so educate yourself before you proceed :) I'll post more pictures and a schematic once I have them ...
Click on the picture(s) for a much larger view :)
|
 |
5hp 3 phase motor I found for $75. I had the hardest time finding something to work with so I had to spend some cash at the motor repair shop for something surplus. He threw on a pair of new grease fittings for nothing. I might just paint this motor gray as well :) |
 |
The motor specs. The motor has cast iron bell housings. It's an older style and makes for a good candidate for a converter. You want an older motor - not real old and not newer style either as it the conversion efficiency is better. |
 |
The internal wiring. Typical of a 3 phase motor. |
 |
I found these at work. These large rubber feet are used for mounting machinery. Figured I could use them :) |
 |
Here is a box I managed to get for nothing. I probably won't use the mercury relay but I'll keep it with all my other goodies for some other project on another day... |
 |
Here's a closeup... |
 |
I decided to paint the motor the same gray as all the other machinery, so here it is masked off after a good degreasing. |
 |
I stripped the box of everything. Now I can work with it... |
 |
Well I happened to come across one of those smaller hand trucks in the trash, still in good shape. Why reinvent the wheel, so I modifed it to accept the motor after acid treating the base plate for rust... |
 |
I cut four small pieces of pipe for spacers. mounted the motor on them to allow access to the rear electrical compartment... |
 |
It's not complete obviously, but this should work out fine. The motor is so heavy it bends the bottom plate on the hand truck so I will need to add two brackets for reinforcement... |
 |
A look at the rear. Keep in mind this whole assembly will be painted grey and look a lot better... |
 |
The large rubber pads will cushion the motor vibrations - I hope. |
 |
Mounting the electrical box was simple. I don't want to weld too much on this so I went with some nuts and bolts. I'm going to trim off the excess protruding bolts to make this more presentable before painting. |
 |
I have the lower brackets and will install them the next chance I get... |
 |
So here we are after welding on two brackets from the lower handle to the motor mounting plate, plus two coats of gray epoxy paint. |
 |
After drawing up a schematic of what I wanted for an RPC I started to mounted some things like the contactor, starter delay relay, start capacitors and about an 8ft line cord. I'll have the schematic up for viewing shortly... |
 |
I spent a good amount of time with some Greenlee knockouts to mount the front panel voltmeter, switches, hour meter and both recepticals on the side. |
 |
I have to say it came out rather nice !! |
 |
The voltmeter will help me tune the phase voltages with capacitors and the three lamps indicate all three phases are live... |
Last updated on 2-5-2008 |