Re: The smoothness of our toroids

To: tesla-at-pupman-dot-com
Subject: Re: The smoothness of our toroids
From: boris petkovic <petkovic7-at-yahoo-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Tue, 28 Dec 1999 11:40:59 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme




> In a message dated 99-12-23 03:41:31 EST, you write:
> 
> << That seems to tell me that the corrugated 5"
> toroid is only 4/(2.5) = 1.6
> > times as good as the smooth 1/4" pizza pan in
> holding off the spark until
> > the voltage can build up, as compared to what one
> might hope from the
> > ratio of the nominal cross-sectional diameters,
> which is 5/(.25) = 20.  
>  
> > Am I wrong? >>
> 
> Ken, all,
> 
> I agree that smooth toroids work better, based on
> tests I did and
> reports by others.  I was able to obtain the same
> spark length from
> a 4" by 13" smooth toroid, as from a 4.3" by 17", or
> a 5.3" by 20"
> corregated toroid.  The corregated toroids tended to
> want to produce
> extra streamers that leaked away the energy.  The
> only way I was
> able to get long streamers using the corregated
> toroid was by
> using a breakout bump on the side of the toroid. 
> The differences
> between the toroids seem to be greater at low
> break-rates.  At low
> break-rates, it seems to be more important to have a
> smooth toroid,
> to prevent lots of small leakage streamers from
> forming.
> 
> Jeff Parisse reported that in a large system, the
> sparks were unable
> to break out of a particular large smooth toroid at
> all, but they broke
> out easily from a corregated toroid of the same
> size.
> 
> Holiday Cheers,
> John Freau
> 
> 
> 
Hi Terry,John ,List,
 
I'm also intersted in such effects.Hmm..the smoothness
of big top electrode and its breakdown voltage.
One might be quite suprised by significant lack of
correlation between theoreticaly predicted breakdown
voltage and measured voltage required for starting the
effect of visible corona apperance per see.
For example,according to theory, under normal standard
conditions ,with Ecritical=30 KV/cm  for 24"/8" smooth
toRoid break down V should be about 300 KV.
Curiosity : in the range of ~200 khz coil,measured
peak voltage in SINGLE PULSE MODE test has been in
excess of 330 KV and there hasn't been visible any
corona issuing from the toroid (IMHO ,for that unit
time interval of 0.7 microsec. ,when voltage peaks
over 300 KV isnt sufficient for corona to develop at
all-whatever some HV books might say about it!).
In oppositon to that I'm pretty sure that during
120BPS mode of operation 24",8" same smooth toroid
throws sparks even in the case of max voltage being
somewhat lower than 300 KV.

Regards,and Happy N.Year  
Boris      
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