On 2009-01-19, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

Absolutely. No need to couple them mechanically.

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

I have a phase converter with two idlers, which has a lot of benefits
and no drawbacks. My idlers are 10 and 7.5 HP respectively. Using a
lot of 1-3 HP motors would be messy, but not really electrically
infeasible.

What were you quoted on a 7.5 HP motor?

Would you be interested in a new Reliance 10 HP motor?

I do not think that in a HSM context, you need a new motor for an
idler. Even used motors have thousands of hours of service ahead of
them, and phase converter does not load the bearings with anything
besides the weight of the rotor.

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