Re: arrgh! ignition coil failure!

["Ed Phillips" <evp-at-xxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Tesla list wrote:
> 
> Original poster: Hhchicken1-at-aol-dot-com
> 
> I don't think the dimmer's at fault, because I tried it with an ordinary
> switch, with the same result :(
> 
> Henry

	I think that says the dimmer IS at fault (shorted).  Try Terry's
suggestion to check it with a light bulb.  By the way, the role of the
dimmer in this application is completely different from its normal one. 
It is acting as a switch to discharge the capacitor through the coil
primary; this happens very rapidly when the triac fires.  Furthermore,
after the first cycle, the capacitor ends up being charged to the line
voltage, so that as the triac fires on alternate half cycles the
capacitor is really charged to twice the peak line voltage.

	I have found that the best setting for the dimmer pot is at the point
where a lamp would be the dimmest, and that advancing the setting to
"brighter" may cause it to stop working altogether.  Biggest capacitor
I'ved used is 3 ufd, which works just fine.

Ed