Re: Coupling vs secondary voltage chart

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

Hi Boris,

On 17 Jun 2005, at 12:43, Tesla list wrote:

> Original poster: boris petkovic <petkovic7@xxxxxxxxx>
>
>
> Hi Malcolm,
>
>
>  > One system I took
>  > to critical coupling required elevating the
>  > secondary more than 3
>  > feet above the primary. Also, power transfer is
>  > getting pretty lossy
>  > at critical coupling as the inherent coil losses
>  > become significant.
>  > The possible voltage maximum would be less at
>  > critical coupling
>  > because of these losses. Consider: an ideal
>  > (lossless) transformer is
>  > always depicted with k = 1.
> -----
> Thought I have been pondering over the years  :Is it
> always true that the longest arcs from disruptively
> operated TC must be the ones that dissipate the
> highest power?
>
> My gut feel is this might not be always the case.
>
> Longer rise times (over more rf cycles) are good for
> arc propagation and they are achieved by lowering the
> coupling.
> On the other hand,as you said,too low coupling results
> in primary spark gap (or IGBT),and primary in general
> ,chewing up more percentage of the available power.
> There must be optimum choice(s) between these two
> factors affecting performance for every separate
> system under consideration.

It is not only switch losses (whichever type of switch might be being
used). My tests to get the result noted above excluded any kind of
switch and were done CW from a lo-Z series feed to the primary. At
critical coupling under those conditions, the inherent coil losses
are pretty much the only losses present.

Malcolm