[Prev][Next][Index][Thread]
Re: Inductor question
On Sat, 7 Sep 1996 10:25:25 -0600, Tesla List
>From: Mike McCarty <mmccarty-at-dnaco-dot-net>
>To: tesla-at-pupman-dot-com
>Subject: Re: Inductor question
>
[snip]
>The permeability of different types of steel vary a lot from alloy to alloy.
>A permeability of 5 is terrible. 99.9 % pure iron has a max permeability of
>around 5000. The very best alloys for this kind of work have a high nickel
>content and can reach permeabilitys of 800,000. I'd experiment with different
>kinds of steel before you put too much work into winding a nice inductor.
>
[snip]
>A co-worker and I were goofing around one day and wound a bunch of #10
>THHN around a 3" PVC pipe. We jammed the wires into a wall outlet and
>turned on the power. With a peak reading ammeter we pulled 60 amps
>before the 20 amp breaker tripped a split second later. We took a piece
>of heavy wall steel pipe and inserted it and we were able to hold the current
>just under twenty amps.
60A/20A looks like 3 to me.
Don't forget that this permeability of 5000 is in series with Air of
permeability ~1.
jim