On 2013-06-20, Karl Townsend wrote:
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

FLA

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor

FLA -- but how are you going to run them on two separate circuits,
when one starts another?

2b. what wire size for above motor

See FLA and AWG table

3. How much start caps for the 5 hp motor?

Try 100 uF, it differs from motor to motor as to how much will start it

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.