Re: 'suicidal' glass plates

To: tesla-at-pupman-dot-com
Subject: Re: 'suicidal' glass plates
From: Jim Fosse <jim.fosse-at-bdt-dot-com>
Date: Tue, 01 Oct 1996 01:15:47 GMT

>>From: "Kevin D. Christiansen" <kdc4n-at-cs.virginia.edu>
>>Subject: Suicidal glass plates

>>I then sat the whole unit on the carpet in my appartment
>>and slowly charged the capacitor up (with DC voltage)
>>by using a 15 KV neon sign transformer and a full-wave
>>rectifier, with a variac to control the output voltage
>>of the transformer.  When I got up to about 12 KV (DC),
>>the bottom glass plate broke!  Remember that the glass
>>plate is not even part of the capacitor - the capacitor is
>>simply sitting on the plate!  I then continued increasing
>>the voltage, by slowly turning the knob on the variac.
>>Around 17 KV, the top glass plate broke!  (Note that
>>here is no weight piled on top of the capacitor, either.)
>>Furthermore, I saw no corona anywhere (like you see when
>>a cap is used in a tesla coil).
>
>>What is going on here?  I know that these glass plates
>>can handle _at_least_ 22 KV, since these plates were
>>previously part of another glass/aluminum foil capacitor
>>that I had made, and I routinely charged it up to 22 KV (DC).
>
>>Ideas?
>
>	Speculation...
>
>	Voltage greater than 22kv was present???
>
Kevin,
	How about a series LC circuit multiplying the neon's output
voltage by the Q of the LC circuit.  In your old TC you had a load -
the arc - to limit the voltage. Here, there was no load so the voltage
increased until something gave. What is the reverse voltage limit of
you HV bridge? I would guess that the bridge has a much higher reverse
voltage breakdown otherwise the bridge would have blown rather than
the glass.

	jim