In article , Ignoramus19508 says...

Thanks to all. I have another question. For a phase converter motor,
how important is the RPM? I am a little puzzled that 3 phase motors
have different RPMs, 1740, 1750, 1800, 1760 etc. I cannot understand
how it can be with 60 HZ incoming power.

Get the Audel;s motor book. It explains about the number of
"poles" in an induction motor, and how induction motors work.

In any case, with a motor that is not spinning at exactly 1800 RPM,
how would the third leg agree with the incoming 60 Hz frequency? I am
quite confused.

The rotor in an induction motor sets up a rotating B field inside
the stator windings that is locked to the line frequency. Because
the windings are installed in the stator with correct spacing to
give the poles the correct phase relationships to each other, the
three wires automatically give you correct 'factory' three phase
at the output.

It's not magic, it's just a natural result of how polyphase induction
motors work.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================