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Re: 50%

At 05:25 AM 11/7/96 +0000, you wrote:
>From MALCOLM-at-directorate.wnp.ac.nzWed Nov  6 21:29:05 1996
>Date: Thu, 7 Nov 1996 08:11:00 +1200
>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 ]