Thanks for explaining your thoughts. I agree that switching in an
inductive load would worsen the power factor. But if you correct the
power factor for a motor while it is idling, and then load the motor,
only the real current changes and there is no need to change the amount
of capacitance used for power factor correction.

I don't think it is important to correct power factor in most cases.
The exception in my thoughts is fairly large welders which have very
low power factor when energized and no welding is going on. In that
case one can get by on a smaller breaker. Breakers over 60 amps jump
in price.

Dan



DoN. Nichols wrote:

Well ... when you switch on a load (typically a machine motor),
you are adding predominantly an inductive load, and it will probably
work out to close to resistive only when the motor is near full rated
power -- that is heavily loaded -- so you would need more capacitance to
tune out that additional inductance during most of the time. (Do you
always push your machines to the maximum that their motors can handle?
Even when taking finishing cuts?




I could accept this if the load motor were connected full time.
But I don't think so with the load motor being switched.

Enjoy,
DoN.

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