Re: arrgh! ignition coil failure!

[Hhchicken1-at-xxxxxxx (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

I tried the dimmer with an ordinary light bulb, and it stays at what I guess 
is maximum brightness for the whole range on the dimmer.  So tomorrow I'll 
get another dimmer, which should hopefully fix it!  Thanks for your help Ed 
and everyone,  I had no idea that the dimmer was so important :) 

Another idea - would the coil run satisfactorily off the 12v side of a 
240v-12v transformer? 

Thanks everyone, 
      Henry 

In a message dated 19/11/00 20:15:35 GMT Daylight Time, tesla-at-pupman-dot-com 
writes: 



>
>    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