OK, after extensive google and research this evening I've come up with very
little. I have access to an amazing amount of 3 phase motors going up into
some really high horse powers (10,000 horse, but I can't have that!
hehehehe). I plan on building a cyclone dust collector (needing a damn
inpellor too, but that's another story) and would like to acquire some three
phase tools over time as well. The rotating phase convertors are pretty
expensive but aren't too hard to build from what I understand as long as you
know electricy. I've got that covered as well as my brother-in-law is great
electrician. He needs to see a plan for what is needed though. What I want
to build is a phase convertor with a three phase motor to convert the third
leg and a small motor to kick start the three phase motor. Has anyone seen
any plans, either at a price or free that I could use to get this built?
Most of what I've seen indicates a capasitor and lots o wire. Haven't
decided whether to build a motor shut off for the starter or a just use a
pulley system. Anyway, any help from you fine folks would be appreciated!
Thanks in advance!
I have 3 mills and 1 metal lathe that are 3 phase in my shop. I have an old
10hp 3 phase motor that I use for a rotary converter, have been using this
setup for years (close to 10) now.
The three phase for your machines connects to the 3 leads of the motor you
are using for the converter.
Single phase goes to any 2 of the 3 leads on the converter motor.
Spin the phase converter motor up to speed before you turn on the power to
it, I use an old 1/6hp 120V motor for the pony motor.
Once the pony motor has the 3 phase motor spinning up to speed, switch on
the single phase and you can turn the pony motor off.
You now have 3 phase for all your shop.
You can add run capacitors to balance the phases and help correct the power
factor. You can also add start capacitors so that you don't have to use a
pony motor, but you need to switch them out when the converter is up to
1 Ph IN----MOTOR-------3 Ph OUT
Where are you located? Please say someplace close to Tucson, AZ......
You understand correctly.
You don't really need the "pony" motor to start the idler. It does work,
and well, but it also increases the mechanical complexity (unnecessarily
IMO, for most applications). A starting capacitor can accomplish the same
Then use Google Groups Search ("balancing converter
group:rec.crafts.metalworking" is a good start) to learn how to balance
the legs and finally the power factor. Look for tips from Fitch Williams;
he's da man. Bob Swinney has posted some helpful stuff on the topic, too.
There are pictures and the schematic for a 10 HP rotary
converter I built for a friend at:
P.S. You can ship me some of those big ones :)
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