Re: Over Saturation?

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

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

"Not too much of a reflection on you, any people involved in electronic
design don't understand this one either! Often people ask "how much can
I load it before it will will saturate?" or something similar, but
increasing the load actually moves a transformer further from
saturation. Increasing the supply voltage or reducing the frequency
causes saturation as it is the volt-second product that is the critical
issue.

The formula n/v =1/ 4.44BFA tells you what the flux density is.(B)

F= frequecy
a= Area of the core in Metres
n/v = turns per volt

George Tyler"

	Very timely note.  A few questions:

	Do you mean area in meters^2?  (This is the US, hence the meters but
they are all the same of course.)

	Flux density in gauss or Tesla?  I'm used to using core area in cm^2
and gauss (I'm an old timer) and haven't tried conversion of your
formula.

	Final point is you should include the allowable flux densities for good
transformer "iron" and also for typical ferrite core materials.  	see a
lot of reports here of guys winding NST protection "chokes" by wrapping
a few turns of wire around a loop core or something like that.  Doesn't
take much calculation to see that the core isn't doing anything.

Ed