RE: Counterpoise and MMC demise

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Steve,

On 20 Jun 2003, at 7:37, Tesla list wrote:

 > Original poster: "Stephen Conner by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>
 >
 > At 18:37 19/06/03 -0600, you wrote:
 >
 >
 > >??  If the gap is set to fire at some voltage it will fire at that
 > >voltage. The cap can't ring up beyond that voltage.
 >
 > That ain't so... There is a lot of uncertainty in the firing voltage of
 > static gaps, it varies depending on dv/dt, electrode temperature, and
 > whether a cosmic ray or U.V. photon happened to hit the electrodes as the
 > voltage was at its peak. The uncertainty is easily enough to let the cap
 > ring up to voltages that will kill your NST power supply, as several people
 > myself included have found out the hard way :(
 >
 > Steve C.

I agree that there is a modicum of uncertainty in the firing voltage -
several kV at most. This I have scoped. That is a far cry from
allowing a cap to ring up to 2 or even 3x the nominal voltage. A
better candidate for that would be an async gap running at slow
speeds.

Malcolm