Re: Magnifer vs. Tesla Coil

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

Original poster: Paul Nicholson <paul-at-abelian.demon.co.uk> 

Dave G wrote:

 > I think that Richard said that the primary and the capacitor
 > should resonate at 1/8 wave of the secondary coil. ...

 > the frequency off the top of the secondary should be the 1/4 wave
 > frequency that the third coil resonates at.  The 1/8 wave
 > configuration makes sense to me because otherwise it would be
 > difficult to manage all the corona if it were set to run at
 > 1/4 wave.

None of that makes much sense. Resonate at 1/8 wave? ..the 1/4 wave
frequency that the third coil resonates at?

The combination of secondary and tertiary has two resonances
that we are interested in, you can call them 1/4 wave and 3/4 wave
if you want.  Adding in the primary splits the 1/4 wave resonance
into two modes, both 1/4 wave, but with opposite phase of primary
current.

As you increase the coupling on a TC, the level of the 3/4 wave
component increases - ie more and more energy goes into this (and
higher) modes.  The aim of a magnifier is to split the resonant
inductance into two pieces such that the voltage peak of the 3/4
wave mode ends up sitting on the transmission line. This minimises
the voltage stresses along the coils.  The tuning is set so that
the 1/4 wave modes and the 3/4 wave mode combine to create a voltage
peak at the topload, simultaneous with the transmission line voltage
passing through zero, and the primary current and voltage passing
through zero.

Antonio has provided the equivalent description to this tuning, in
terms of lumped values.

So, the magnifier, if you want a definition, is a means to control
and exploit the 3/4 wave mode which would otherwise be a nuisance
if left to take care of itself - the nuisance being energy wasted
and racing arcs.

But remember, the secondary-tertiary resonator simultaneously
resonates at three frequencies [*], and it is wrong to thing of each
resonant mode being localised to a part of the system. Each resonant
mode represents a mutual electrical motion of all components of the
system.

[*] meaning we only consider analysing the main 3 frequencies, we
ignore all the other higher modes that are excited with each bang.
-
Paul Nicholson
Manchester, UK
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