Re: Dimmer as a Variac.

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

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi All,
> 
> Today I got a Leviton No. 6681 600 watt dimmer switch at the hardware
> store.  It cost me about $7.  I imagine these are available everywhere at
> least in the USA.  I pulled the back cover off to expose the electronics:
> 
> http://hot-streamer-dot-com/temp/P7060004.jpg
> 
> Wow!  They sure are cheap!! :-))  All hand tack soldered.  Many
> opportunities for shorting and such...
> 
> The main power electronic device does not have heat sink compound under it.
>  I think drilling out the rivet and adding a little thermal grease will
> increase it's short term power handling about 200%!
> 
> Not enough room inside to add internal MOVs but a little thermal grease and
> some "adjustment" of the guts should help them to survive considerably.
> 
> I am thinking that MOVs and a good line filter will complete the poor man's
> variac and I can do a little testing to see if the idea is worth while.
> Still have to check what the output wave forms look like and see how that
> will affect the rest of the coil...
> 
> Stay tuned...
> 
> Cheers,
> 
>         Terry

	I predict you are going to be very disappointed!  The performance of an
SCR/TRIAC dimmer is very different with an inductive load, which your TC
primary circuit will probably be at the frequencies which commutate the
SCR.  Hope I'm wrong.

Ed