Re: Energy storage in primary?

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

Original poster: "Bert Hickman by way of Terry Fritz <teslalist-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Tesla list wrote:
>Original poster: "Malcolm Watts by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
>Hi Bert,
>On 30 Jan 2003, at 0:23, Tesla list wrote:
>  > Original poster: "Bert Hickman by way of Terry Fritz 
> <teslalist-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>
>  >
>  > Hi Jolyon,
>  >
>  > My response is interspersed below...
>  >
>  > Tesla list wrote:
>  > >Original poster: "Jolyon Vater Cox by way of Terry Fritz
>  > ><teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
>  > >So the primary oscillation will not be quenched when the switch turns on
>  > >again -short-circuiting the primary capacitor?
>  >
>  > The goal of quenching is to strand energy in the secondary side at the
>  > appropriate time by opening the primary LC current loop. If we short
>  > circuited the primary capacitor instead, this has the effect of short
>  > circuiting the primary inductor, but it still leaves the primary as an
>  > "active" element in the primary-secondary magnetic circuit. The primary
>  > would behave as a short circuited transformer winding, robbing energy from
>  > the secondary resonator. To achieve a proper quench, the primary current
>  > loop must be broken.
>Actually, if the primary coil was superconducting, it should achieve
>the same goal since the coil would then be incapable of absorbing
>energy although one would imagine that it would alter the "isolated"
>secondary characteristics in some interesting ways. This could be
>something for the TSSP project to have a look at. Perhaps instead of
>asking a lot of questions, people should actually try some of their
>ideas out and report to the list. The next design breakthrough could
>be just around the corner.
>Regards,
>Malcolm

Hi Malcolm,

You're absolutely right. Practical primaries at room temperature normally 
have Q's that are significantly lower than that of a well designed 
secondary. Short circuiting the primary inductor in this case will also 
decrease the effective Q of the secondary making system performance 
inferior compared to opening the primary current loop. However, using a 
superconducting primary would make it as a reactive load (less small 
radiational losses), and the secondary would only lose a little energy to 
the primary system. Coupling to the short circuited primary inductor will 
also reduce the secondary's effective inductance, raising its resonant 
frequency.

A first order approximation using simple lumped parameter analysis 
indicates that the secondary's inductance would decrease from Ls to 
Ls(1-k^2). This will slightly increase the secondary's resonant frequency 
(by a factor of 1/(sqrt(1-k^2) or about 2% when k = 0.2).

Best regards,

-- Bert --
-- 
Bert Hickman
"Electromagically" (TM) Shrunken Coins
Stoneridge Engineering's Teslamania
http://www.teslamania-dot-com