Re: calculating inductive factor for c cores

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>




> > A simple equation turns
> > this mess into a turns/volt figure for the core and if the primary
> > occupies around 40 - 45% of the total winding window, the magnetizing
> > current will be a low percentage of the reflected load current at the
> > core's VA rating. The equation can be boiled down to:  turns/volt =
> > 7.164/Ae for the 60Hz mains.
>
>         This expression should be burned into the brains of ANYONE thinking
>about running a 120V NST on 220V, etc.,etc.  If you try to increase the
>voltage across a coil/core very much beyond the design value the
>magnetizing current will go out of sight and all of the smoke will come
>out of the winding.
>
>Ws

This is a handy thing to know when looking at those surplus transformers at 
the scrap yard.  The other handy one to know would be a rough and ready 
"size of transformer" to "rated VA", which I used to have at the tip of my 
fingers, but can't seem to find right now.