Re: Power factor correction capacitors for MOTs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: tesla-at-lists.symmetric-dot-net 

You only need power factor correction if there is enough reactive current
to trip your breakers or make your wiring too hot.

Trial and error will work as long as you have an AC current meter. I
suggest an analog one. Cheap digital meters give nonsense readings for
strange waveforms which you may encounter with funky transformers.

Connect the transformer to the current meter and measure the durrent draw.
I'd suggest doing this with no load on the transformer. STart to add ac
rated capacitors across the transformer primary winding and watch for the
current draw to the transformer to drop. It will keep dropping until you
have too much capacitance at which point the current will start to
increase.

You can do the same thing with the transformer under load as well, but
will probably need more capacitance. The basic idea is the same-to cancel
out reactive currents from the transformer (inductor) with capacitors.

KEN


On Wed, 10 Nov 2004, Tesla list wrote:

 > Original poster: "Borislav Trifonov" <bdt-at-shaw.ca>
 >
 > How do I determine the proper PFC cap, or if I even need one, for a
 > MOT?  Mine has been modified by removing the magnetic shunts and
 > reassembling the laminations so that they are interleaved, so I don't know
 > how that affects the usual numbers used.  I don't know how to measure PFC
 > and I don't have a scope.
 >
 >
 >