[Prev][Next][Index][Thread]

Re: Solid State article on website

Hi Malcolm,

At 04:56 PM 5/24/00 +1200, you wrote:
>Hi Terry, all,
>                    I have a number of comments to make on the paper 
>referred to. I conducted expts using a bank of MOSFETS in place of
>the gap a few years ago using a 30V DC supply and wound up 
>producing 1/2" sparks under some conditions.
>
>On 23 May 00, at 18:30, Tesla List wrote:
>
>> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>> 
>> Hi Bob,
>> 
>> 	WOW!!!!  This paper is a pure treasure!!!  Very highly recomended to all!!
>>  The paper at:
>> 
>> http://www.stellarproducts-dot-com/synch.htm
>> 
>> Also has significance to us doing other Tesla coil secondary behaviour
>> stuff (the "Malcolm's Ruler" model) we haven't told you all about yet ;-)))
>> 
>> I do not know this Dr. Bruns but he seems like a very interesting person
>> who is very knowledgeable in these areas I like so much!  :-))
>> 
>> Cheers,
>> 
>> 	Terry
>
>Points I would like to note:
>
>(1) He says that Cself was inferred from measuring the frequency 
>but I didn't see the formula he used. Presumably it was the classic 
>lumped resonance formula. Anyone see it there? It would appear 
>that he was measuring Medhurst's value for Cself.

He apparently had a large value fixed cap on the end of the secondary that
overwhelmed the coil's own self (Medhurst) capacitance.  Just the end
capacitance and the coil's inductance should have given a number close to
the resonant frequency allowing the coil's self C to be neglected.

>(2) He connected a comparatively huge lump of C across his 
>secondary to bring Fr down. Anyone see something wrong with 
>doing that (if this is supposed to be indicative of a normal TC 
>configuration)? Maybe not.

It may have a bad effect on a transmission line model but should not make
much theoretical difference in a pure lumped model.  I imagine he simply
did what he had to do to get the thing to work ;-))

>(3) There was an indication in one of the oscillographs that his gap 
>quench was less than perfect on at least some occasions. It showed 
>up as a residual beat in the primary waveform and a matching dip in 
>the secondary ringdown envelope.

His fancy FET switch could quench whenever he wished.  I notice in one
graph he turns the gap off in the middle of the second ring up and has his
computer model do the same.  Perhaps he was searching for the coherence
voltage rise predicted in the Corum's old paper ;-))  It is also
interesting to note the very low voltages he was working with.  I imagine
he had relatively perfect control of his given setup.

Cheers,

	Terry


>
>I'd be interested to hear other's comments on the paper.
>
>Regards,
>Malcolm
>
References: