Re: Energy storage in primary?

["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 Terry,
            One further note to my last one in reply:

On 28 Jan 2003, at 12:52, Tesla list wrote:

 > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
 >
 > Hi Malcolm,
 >
 > Yes!!!  A car ignition coil may be the perfect coil for this.
 >
 > One would have to use say a GM HEI coil with the core cut away to get a
 > "true" loosely coupled Tesla coil.  Then an electrode could be added and a
 > suitable cap found for the primary that would tune the system.
 >
 > Unlike the GMHEICSLR thing, current would be the main driver.  So the gap
 > would be replaced with say an IGBT and a current source (only a few amps
 > now, a plain battery...) would drive the system.
 >
 > I worry a little about the voltage kickback, but were only starting with a
 > few amps so maybe it would not be too high for say a 1200V IGBT.  I would
 > think such a system could easily get to Jolyon's 6 inch
 > requirement.  10kHz, 3 amps, ??? inductance, 1.7uF capacitance...

I mentioned placing the primary cap across the switch. What should be
done to minimize the risk of damage to the switch due to it drawing a
spike of current from the charged cap (one presumes the cap will be
charged to the supply voltage prior to the switch closing) is .....
well there are all sorts of options open which could lead to some
interesting and innovative circuits to get around the problem, and
possibly quasi-resonant self-tuned CW operation as well by active
monitoring of cap voltage while the circuit is ringing. I might have
a little scribbling session during my lunch hour.

Regards,
Malcolm
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