Re: Spark Gap (fwd)

---------- Forwarded message ----------
Date: Mon, 25 May 1998 08:46:21 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Spark Gap (fwd)

Hi Marco,

> Date: Fri, 22 May 1998 08:55:04 +0300
> From: Marco Denicolai <marco-at-vistacom.fi>
> To: tesla-at-pupman-dot-com
> Subject: Re: Spark Gap
> As a beginner, I have to ask this. When the main spark gap is supposed to
> trigger ?
> 1 - When the tank capacitor is changed at full voltage (1.4 * transformer VAC)
>       OR
> 2 - When the tank capacitor is changed a suitable voltage LOWER than that?
> If the correct answer is n.2, so what is the benefit of having a 14 kV
> transformer if the capacitor is discharged always at e.g. 8 kV?

It charges and discharges more than once per half cycle. However, 
I've found that results are better with the higher tank energy 
discharged less frequently. It may be different for different coils.

> With my (supposed) 8kV tank I can get 0.37 inch sparks so that using a, say,
> 0.15 inch gap would reduce my used voltage to about a 40% of the available...

That gap is firing at a far higher voltage than 8kV. Far higher. 

> More, isn't that shorter gap much more difficult to quench than a wider gap?

Depends on the charging inductance and primary capacitance. A large 
capacitance loads the supply heavily and makes the charging voltage 
rise more slowly.