RE: [TCML] Induction heating by closed coil

[Jeff Behary <electrotherapy@xxxxxxxxxxx>]

Hello,
I've done induction heating of steel with Tesla Coil circuits, but having no secondary coil.  Just the transformer, condenser, spark gap, and primary coil.  The primary coil itself was used to do the heating, I included a metal core onto which the primary was wound (in the form of a steel tube with a welded bottom) which would get hot from the high frequency currents.  The best I was able to do is simmer water, at the expense of 2000 watts.  But if someone really researched the topic they might have better luck, I was just playing with some junk.  
 
I can imagine every Tesla Coiler with a new form of electric kettle, complete with mica condenser and adjustable spark gap.  Probably the most inefficient tea kettle ever designed, but you must admit it would be an eye-opener for the guests!
 
But seriously, somewhere I read (perhaps the Machinery Handbook) some frequencies used for commercial induction heating of metals, and at least one of them falled into the category of Tesla Coil frequencies.    I want to say it was iron or steel, surface hardening only, and around 100 khz.  Not sure of the power levels needed, but it might be interesting to try with a few kilowatts to surface harden a 1/4" diameter steel rod, to make a small shaft or something...  
 
I have some large diameter tungsten, 1 1/4", maybe I can try a quenched spark gap arrangement, low voltage transformer, and high current to see what happens. . .
 
Jeff Behary
 
> From: 16108volts@xxxxxxxxx> To: tesla@xxxxxxxxxx> Date: Tue, 29 Jan 2008 08:57:07 +0100> CC: > Subject: [TCML] Induction heating by closed coil> > Did anybody tried to construct induction heating system which has closed (or > shunted) coil as secondary? Tesla patented some motors with that type of coils, > and I have few motors (not of that type) for playing, with plenty space inside > them. But I don't like this idea of shunting coils without some independent > opinions.> > S.Igor > > _______________________________________________> Tesla mailing list> Tesla@xxxxxxxxxxxxxx> http://www.pupman.com/mailman/listinfo/tesla
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