[AMRadio] Ferroresonant transformer revisited

W5OMR/Geoff w5omr at satx.rr.com
Sun May 7 07:14:38 EDT 2006

Jim Candela wrote:

>    The ferroresonant transformer is not really
>resonant at all since the winding that feeds the
>capacitor is wrapped around a portion of the core
>that is a saturable reactor. Resonance and saturable
>reactors don't really go together, but in this case we
>do have circulating energy in a ferroresonant
>transformer which consumes about 20% of the VA rating
>of the device. So for a 1 KVA ferroresonant
>transformer the power draw when unloaded may be about
>200 watts, and this is pretty much a constant.
>Therefore with a 1 KVA load, the power input would be
>1.2 kva. Every line cycle runs the core into
>saturation, and this creates eddie core losses, heat,
>buzz, and a quasi square wave output. The output is
>not a sine wave unless yours has a harmonic filter.
>Therefore a true RMS meter is needed to accurately
>measure the AC voltage.
>These are really neat devices using very old

which covers everything *except* what Rick asked, Jim (grinz).

How hot is the darn thing -supposed- to get?  I, too, wouldn't think 
that it's hot enough just sitting there, with no load, that you couldn't 
put your hand on it..


More information about the AMRadio mailing list

This page last updated 15 Dec 2017.