Re: Low Voltage Tesla Coils

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 
> Original poster: "Justin Hays by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<pyrotrons2000-at-yahoo-dot-com>

> ** But, maybe the applied voltage (across the primary) could be held
> on for even as long as a few tens microseconds, letting the current
> build up to several hundred amps (have to calculate that...probably
> way off) THEN release it, and let the field collapse into the
> secondary and ring the heck out of it. Like an ignition coil.

An induction coil circuit may be a solution, but energy conservation
still says that the voltage gain is limited by the ratio of
inductances. Not anymore by sqrt(L2/L1), but by something similar
if the coupling is low. So, as in an induction coil a large
secondary inductance would be necessary for a feasible
primary inductance.

I recently wrote a paper showing design equations for an induction
coil circuit that operates as a Tesla coil, but with the primary
energy initially in the inductor. See the paper:
"Generalized multiple resonance networks"
In:
http://www.coe.ufrj.br/~acmq/papers

The design equations for the 2-coils system (L1, L2 with coupling
coefficient k12, in parallel respectively with capacitances C1 and 
C2) are:

w^2*L1*C1=1/(k*l)
w^2*L2*C2=1/(k*l)+((k-l)/(k*l))^2
k12=sqrt((k-l)^2/((k-l)^2+k*l))

Choose k and l as two integers with a difference that is a double odd
number, as 1-3, 10-13, etc. The system oscillates at the frequencies
k*w and l*w rads/s during the energy transfer, that takes pi/(2*w)
seconds.
Note that for the fast modes (k and l low) the two coils are
tuned to quite different frequencies, and k12 is high, but for
the slow modes (k and l high and differing of 2) the system
resembles a regular Tesla coil, with low k12 and L1*C1 almost
identical to L2*C2.

The paper shows also design formulas for a magnifier-like
induction coil.

Antonio Carlos M. de Queiroz