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Re: Inductor question
Tesla List wrote:
>
> >From sroys-at-umabnet.ab.umd.eduThu Sep 5 22:15:14 1996
> Date: Thu, 5 Sep 1996 12:04:10 -0400 (EDT)
> From: Steve Roys <sroys-at-umabnet.ab.umd.edu>
> To: tesla-at-pupman-dot-com
> Subject: Inductor question
>
> I am playing around with a variable inductor that has a 4" diameter
> sliding core packed with 20 pounds of welding rods (idea compliments of R.
> Hull) that I plan on using to regulate the current in my 50A controller,
> and I have a few questions.
>
> I don't really have the right wire to wind it with yet, so I just wound it
> with some heavy wire (2 or 4 gauge maybe with fairly thick insulation)
> that I had to see how it works. There aren't a lot of turns in the 13"
> winding length, so the inductance is pretty low, but I noticed that the
> difference between the core being totally out of the winding and totally
> in is less than a factor of 5. Is this reasonable for 20 lb of iron
> welding rods or could something else be screwed up? Using Wheeler's
> formula for the inductnace of an air-core solenoid, I compute a value
> that's pretty close to what I measured with the core out, but I would have
> thought that the iron would have made much more of a difference. Would
> winding a coil with 6 gauge magnet wire (which would give me a much higher
> inductance to start with) make more of a difference?
>
> Thanks in advance.
>
> Steve Roys.
Steve,
you could wind it with 8 gauge magnet wire (this will handle 100 amps
easily for short duty Tesla work. You are allowed to wind multiple
layers and tap each layer as you go, you know! (switchable ranges) Just
a few layers will be more than enough. I would probalby wind the thing
with #8 gauge THHN insulated wire, myself.
Richard Hull, TCBOR