Re: coupling coefficient

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

Original poster: "Jolyon Vater Cox by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Is there really any benefit to be had in increasing the primary capacitor
value (and reducing the number of primary turns) when the coupling then has
to be reduced to avoid racing sparks -and doesn't the use of a larger
topload reduce the incidence of racing sparks also?

Jolyon

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, June 13, 2003 3:37 AM
Subject: Re: coupling coefficient


 > Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
 >
 > Tesla list wrote:
 >  >
 >  > Original poster: "Christoph Bohr by way of Terry Fritz
 > <teslalist-at-qwest-dot-net>" <cb-at-luebke-lands.de>
 >
 >  > I had my coupling adjusted when I had a 30nF primary cap. Will this be
 >  > still OK if I change to 60nF or more primary capacitance or will I have
to
 >  > decrease coupling due to higher excitation with bigger bangsize?
 >
 > The coupling coefficient depends only on the configuration of the coils.
 > With greater primary capacitance, you will need less primary inductance,
 > and this will change the coupling a bit due to the different geometry.
 > If the primary charging voltage is the same, the output voltage will
 > be bigger (about 1.4 times). If your secondary coil is insufficiently
 > insulated, this may cause "racing sparks", and you will have to
 > decrease the coupling. The racing sparks, I think, will eventually
 > disappear because with lower coupling the losses increase, the maximum
 > output voltage decreases, and the voltage gradient along the
 > secondary will be smaller.
 >
 > Antonio Carlos M. de Queiroz
 >
 >
 >