Phase converter how-to

There's an excellent article on the web by Jim Hanrahan about how to
build a rotary phase converter, including details on how to make it
self starting and how to size and use capacitors to balance the
voltage from phase to phase. Google for phase converter and
hanrahan and you'll find it on any one of several sites.

A few years ago, I talked with a retired EE who spent his career at
Onan (generator manufacturer). He had built a lot of rotary
converters and recommended that older motors make far superior
converters as compared to the newer and lighter ones of the same
size. He said to look for some big old ugly thing with cast iron
end bells as opposed to the newer motors with fabricated steel
housings. I think he said motors made prior to 1960. As I best
recall, he said as motors have gotten smaller for a given
horsepower, it has altered the current saturation levels, which
results in the newer motors being less desirable for converter use.
Of course, for the hobbyist, older ones are cheaper too, so that's a
win-win.

Cliff