Re: Phase converter circuit

Mark:

I've cobbled a phase converter together from an old large 3 phase motor.
I use a small starting motor to spin it up to speed rather than starting
caps. Spin it up to speed before throwing the switch to the large motor.
Once running the starting motor can be turned off. I've had no problems
with voltage sag.

Hugh Currin
Klamath Falls, OR

On 17 Oct, MARKEHLE wrote:
> While we are talking about it, I would suggest building a rotary converter -
> if you find the parts used, it can be really cheap. I made one out of a 15hp
> motor from an old elevator. The whole thing probably cost me $150, including
> the 3-phase 220-to-440 transformer that is mounted on the side of it to run
> VFD's. With the rotary converter, I get full output from the drives.
>
> It works great... except...
>
> Every time I turn it on, the high-pressure sodium and mercury vapor lights
> in my shop go out, then come on a few minutes later. Does anybody know how
> to reduce the starting current on one of these things? I built it so that it
> starts itself, using a small timer to cut the start capacitors out when the
> rotor come up to speed. Would it help to put a pony motor on it to bring it
> up to speed first?
>