In article ,
footy wrote:
40.96A isn't likely to make a typical properly functioning 40A breaker
trip soon enough to be of concern

If the breaker is functioning properly, and the breaker is tripping, you
have an overcurrent condition. Running a 10HP motor on a 10HP rotary
phase converter is pushing it. I would replace the breaker and see if
that resolves the problem. You may want to upsize the cable a few sizes
to minimize voltage drop and therefore current draw. Otherwise IMHO you
are looking at upgrading the circuit (breaker and wiring) to handle the
required current.

You also might be able to reduce the current enough to avoid the
tripping if you take the time to tune your rotary converter. You will
need to add capacitance across the single phase input in increasing
values until you have the current when driving the load to a minimum.
(Too much capacitance will start the current to increasing again.) At a
guess, you probably want the capacitance value to minimize the
single-phase current ad about 75% of the way from an empty tank to a
full one.

Without tuning capacitors, the reactive current is significantly
larger than with a proper turning capacitor. (This will also probably
save you some electricity costs.)

I hope that this helps,
DoN.
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