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Re: 50%

By "dwell" as applied to a rotary gap I mean contact closure time 
(gap fire time). I realise that is counter to the automobile 
definition.

Malcolm

> >From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: 50%
> >
> >Hi Jack,
> >
> ><snip and points noted>
> >> Higher K's would be a factor with magnifiers but are not involved with
> >> losses. The K should be selected for optimun transfer time. I am not certain
> >> how the K factor equations should be optimized. Do you have any information
> >> on this type of optimizing?
> >
> >I can only reiterate the standard equation for this which I have 
> >thoroughly tested with different coils with different Fr's and at 
> >different k's and have yet to find wanting:  optimum dwell = n/2kFr 
> >where n is an odd number belonging to the set of positive integers.
> >The first ringup to maximum is when n=1 of course. The subsequent 
> >ringups all show a loss of energy to the system.
> >     I also did some thinking on the question of critical coupling 
> >last night and have come to the conclusion that it might not be 
> >applicable to our pulse driven coils. I'll post later on this if 
> >anyone is interested.
> >
> >Malcolm
> >
> ------------------------------------------
> 
> Malcolm -
> 
> You brought up something that needs checking. I have only seen that equation
> in Corum's book. It does appear to conflict with Skilling. The word dwell
> bothers me because it can mean advance spark (automobiles) or spark duration
> as in Tesla coils. But with rotary spark gaps the dwell time is dependent on
> RPM and other variables.
> 
> Jack C. 
> 
> [ Just to interject, the advance/timing is what controls the moment that the 
>   distributor points open up, and the dwell is controlled by the gap between
>   the points when they are opened up by the cam on the distributor shaft.
>   With a larger gap, the points are open longer, and the dwell is greater.
>   Therefore, I don't see any conflict between automotive breaker point dwell,
>   and rotary gap dwell. -- Chip, who's spent a night on the roadside thinking
>   about such things ]
>