Re: Secondary size

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


An optimum coil height to dia ratio is approx 4.5:1.  At values less than
4.5:1 arcing to primary or strike rails occur on a regular basis.  If the
coil is too high the coeff. of coupling is lower and less energy is
transferred.
4.5 : 1 seems to work very well.

The potential output of a resonance transformer is equal to it's gain times
the potential input, ie,

Vout = Vinput peak (1.4 x Erms) x sqr (Ls/Lp)    ----    this is called
system gain.

Also inductance of a coil is proportional to n^2 (high number of turns works
good because of this square factor) and also to r^2 (this is the radius of
the coils geometry).  This r squared factor rapidly increases the inductance
(Ls) in big coils so the gain (voltage multiplication factor) is high and
output potential is high.

It's important to note that spark length is more of a function of current
(system power) than potential.  To double the spark length in most systems
the power has to be increased by a factor of 4 (2 ^2).

Hope this answers your question.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > I would assume that the height would be based on anticipated arc length
and
 > the dia would simply fall into using what you can to stay in the suggested
 > height to width ratio.
 > How do you go about deciding how tall the coil should be based on the arc
 > length?
 > Other than aesthetics what is the method for choosing a secondary size?
 > What is the cut off for deciding how short a coil can be with a given
 > anticipated arc length?
 >
 > It seems there are coils that generate longer arcs than the coil is
 > high.  And since the arcs are referenced to ground it seems that is
putting
 > the top load very close to ground with respect to its output.  I know that
 > the toroid slash secondary top will be at the same positive or negative at
 > any one time as the arc and like charges repel so that is what keeps the
 > arcs from going straight down.
 >
 >
 > Ok also if a height is determined what are the advantages / disadvantages
 > for going with the larger diameter coil verses the smaller diameter?  Keep
 > in mind that when I say large or small diameter I am talking about staying
 > close to the excepted rule of thumb for height to dia. ratio.
 >
 > Thanx
 >
 > I will be asking lots more questions so bare with me.  J
 > Luke Galyan
 > Bluu-at-cox-dot-net
 >
 >
 >
 >