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Re: Secondary Research (fwd)



---------- Forwarded message ----------
Date: Fri, 28 Feb 1997 00:19:35 -0500 (EST)
From: richard hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <mod1-at-pupman-dot-com>
Subject: Re: Secondary Research (fwd)

At 09:28 PM 2/26/97 -0700, you wrote:
>
>
>---------- Forwarded message ----------
>Date: Thu, 27 Feb 1997 09:09:24 +1200
>From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
>To: tesla-at-pupman-dot-com
>Subject: Secondary Research
>
>Hi All,
>        I still have a long way to go in this exercise, but thought a 
>preliminary finding might be of interest. It seems clear that the 
>efficiency of a number of power supplies (or use of available power) 
>leaves a lot to be desired. A reality check on one of the largest 
>systems in the survey shows that power getting to the primary all but 
>matches the measured power input. You can check your system by:
>
>(1) Measure power input (watts, not V.A.)
>(2) Multiply break rate by peak capacitor energy (0.5CV^2) to get a 
>figure in watts and compare the two.
>
>    In a lot of cases I've checked so far these two figures are 
>worlds apart. To get maximum efficiency, resonant or inductive 
>charging of Cp is a must. Unfortunately, using neon transformers to 
>best effect like this can result in an early death for them. To be 
>fair, I have assumed that neons are being used right up to peak o/c 
>output voltage. This will not always be the case. You can open the 
>gap so wide that the transformer takes a couple of cycles to swing up 
>to some enormous values halving or reducing rep rate for a static gap 
>even further. Closing the gap to a more reasonable value gets the rep 
>rate to the desirable value but reduces Ec considerably.
>    It would be most useful to have a table of gap settings vs 
>breakdown voltage (which will be somewhat different from DC) but it
>will no doubt vary for different gap geometries. A useful guide 
>though for ensuring neon survival in my opinion. I have read of 
>instances where gaps have been opened up to 1/2" or more. As a rough 
>guide, the gap on my coil here at work fires at around 8kV when set to
>about 0.06" (1/2" rounded tungsten electrodes).
>
>Other comments welcomed of course,
>Malcolm
>
>
>Malcolm,

Finding the actual RMS watts into a TC is not all that trivial or easy!  A
time integration method is a must.  Most amateurs are not really equipped
for this.

Second, the actual setting of the static gap is hyper critical and variable
at best, if true peak firing on the AC sine is demanded. (but could in
theory be accomplished).  I usually run my static gaps to fire at the 707
point on the sine. This gives me at least two pops per half cycle but
sometimes as many as 4 with the same gap setting (quench variability uneven
discharging, circuit losses, etc).  This is real tough to figure for in real
life.  Firing point moves along the cycle and even multiplies on occassion.
I find about 5% of the time I get 4 pops/sine (half cycle) and about 25-30%
of the time I get 3.  All the rest are two popers and are never symetrical
about the wave.