Re: Magnifier questions
Tesla List wrote:
> >From julian-at-kbss.bt.co.ukThu Aug 15 12:27:23 1996
> Date: Thu, 15 Aug 96 13:58:36 BST
> From: Julian Green <julian-at-kbss.bt.co.uk>
> To: tesla-at-pupman-dot-com
> Subject: Re: Magnifier questions
> >The magnifier requires a really special gap system. The coupling between
> >the pri/sec in a magnifier is about 8 times that of a normal small coil
> >so breakdown between primary secondary is normal. To prevent this, you
> >can reduce the coupling a bit, drop the whole thing in oil or insulate
> >with many turns of thick polyethylene sheet wrapped against the inside of
> >the primary. This wrap must extend well beyond the top of the primary
> >almost to the top of the secondary.
> >Finally the tune on the primary is often the lumped tune of the secondary
> >and resonator combined!
> >Richard Hull, TCBOR
> In what way is the spark gap different? Is there some info on this somewhere on
> the net?
The gap must quench with a rapidity which few amateurs can master in most
gaps. A series quench rotary is best. Although a special rotary and
multiple series gap arrangement is often used to advantage. I am unaware
of a net post on the series quench design. RH
> Also if the resonant frequency of a magnifier is the lumped tune of both coils then
> the voltage rise must be greater in the first coil (in volts per turn) than in
> the resonator due to standing wave 1/4 wave. Current being 90 degrees out of phase
> with voltage and current at a maximum means large gradiant in voltage.
Wrong! The greatest rise always occurs in the resonator. RH.
I assume it
> is better to generate the voltage in the resonator if insulation problems are to
> be overcome. So i'll wind the secondary driver from thick wire. Abit of a balancing
> act this, working out a good impedance match between driver and resonator.
This is correct! RH.
> Julian Green.
Magnifiers can be made in a number of configurations. Only heavy
coupling and special gapping will make one outperform a standard two coil
Richard Hull, TCBOR