DrollTroll wrote:
Awl--

What's more important when adjusting capacitor values:
Getting equal voltage between each pair of legs, or balanced current in
each leg? Seems like you can't have both.

Balanced current in the MACHINE TOOL motor, or in the RPC? You
don't care about balanced current in the RPC, and it won't be
balanced, because each winding is doing a different job. (The
240 V line windings are running the RPC, the 3rd leg is
providing the shifted phase.)

What you are concerned about is getting roughly equal current in
the machine tool motor. And, equal voltages on the line DO NOT
guarantee that you have the proper phase shift of the generated
leg. The voltage from the 240 V mains ceter tap (neutral) to
the generated leg should be at 90 degrees to the mains, and
about 207 V. Without an oscilloscope, however, it is pretty
hard to measure phase shifts. If the machine tool motor draws
equal current on all 3 legs, with roughly balanced L-L voltages,
then your phase shift is right.

As long as the current in the generated leg of the RPC motor is
not excessive, I'd ignore it. If it IS much above the nameplate
rated amps, then you need to reduce the caps to bring the
current down.
At equalized voltage, the current through the generated leg is through the
roof.
I'm not too surprised, but what is "through the roof"? twice
rated current? More?
At equalized current, if line L1-L2 is 240, then L1-L3 and L2-L3 are about
230-233, which is not so bad.

What are you complaining about? That is quite good for an RPC.

Jon