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

Re: Peak cap voltage, was 12kV, 30ma TC specs, 42" spark


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Wednesday, September 10, 1997 12:19 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Peak cap voltage, was 12kV, 30ma TC specs, 42" spark

Thank you sincerely John.
                          This explains everything :).......
 
> From:   FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
> Sent:   Tuesday, September 09, 1997 3:36 AM
> To:     tesla-at-pupman-dot-com
> Subject:    Peak cap voltage, was 12kV, 30ma TC specs, 42" spark
> 
> Malcolm, All,
> 
> I finally measured my peak cap voltage on this TC, sort of.  I was
> concerned about scope grounding with the neon tranny midpoint
> grounded set-up, so I installed a potential transformer instead, 
> which allows for grounding one side of the tranny to the scope.
> In previous experiments, I have found that by using the proper
> amount of inductive ballast, I can closely mimic the operation
> of the 12kV, 30ma set-up.  For 42" sparks, the neon tranny 
> draws 720 watts, and the potential tranny draws 680 watts, as
> measured using a Weston analog wattmeter, sync-gap phase
> was left unchanged for the two transformers.  I attribute the
> greater power draw of the neon tranny to the greater losses that
> occur in such a tranny.  Anyhow, the scope showed 32kV peak
> cap voltage.  The gap was firing slightly late, so I should have 
> re-adjusted the sync-gap phase, but I didn't.   The formula shows
> that the caps should be drawing 430 watts, so the 680 watt actual
> wallplug draw doesn't seem too bad.  And who knows how 
> incorrectly the wattmeter may be reading.  Gotta build the Dave
> Sharpe Opto-wattmeter!  The potential transformer is rated at 1.5kVA,
> 14.4kV, but I turn up the voltage on the 12kV neon a little higher (than
> 120V in), so actual voltages are probably about the same.
> 
> Regards, 
> 
> John Freau

So for Vc = 32kV and about 7nF, we are talking nearly 3.6J/bang at 
120BPS.  Some questions arise of course: how does the transformer 
manage to stand it? 
    My test the other day seems a lot more respectable in the light 
of this :)

Thanks again,
Malcolm