Re: frequency vs core saturation

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: scott <scottxs@xxxxxxxxxxx>

Tesla list wrote:

>     Here is a question for all you mathy theoretical technical guys.

I guess that rules me out.

> I heard In physics class tonight,

Tonight?

> that if you use a higher frequency you can use a smaller core for a 
> transformer.  In my mind this means, if you use a higher frequency, 
> you can pump more voltage through your primary, and consequently get 
> more out of your secondary.

Lord have mercy!

> is this beneficial in any way?  Is this even true, or is my logic flawed?

Kinda sorta.

Someone should point you to some fine website explaining magnetics. I 
lost the link. Anyways...

A current in a wire produces magneto-motive force, in MKS units, 
amps-meter. A magneto-motive force causes a magnetic flux density in 
a permeable material, proportionate to its reluctance, just like an 
electro-motive force (voltage) causes current in a resistive material 
proportional to its resistance.

Now, when you have a high-permeable material, you require less 
amp-meters of wire then if you have a low-permeable material. 
Therefore, your I-squared-R losses (copper-loss) is much less, and 
you can use reasonable & cheap semiconductor to switch the lower currents.

Perhaps the best way to think of it is in mechanical terms:
Work Done = Force X Distance.

Electronically,

Work Done = Amp-Meters X Magnetization

Now with transformers, every trip from + and - and - to + current is 
like a shovel of charge. So if you shovel a little bit of charge tens 
of thousands or millions of times per second, its much better than 
shoveling a lot more charge fewer times per second, especially since 
that takes lower-resistance, bigger expensive semiconductors.

Hope that helps.

Scott