Re: Secondary size

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

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


Keep your coilform dia as large as practical.  An 8-10 inch dia for even a
small coil will give much longer sparks due to it's overall higher
inductance ratio (sqr (Ls/Lp).  A 2 inch dia. coil won't cut it --- too low
inducance ratio because IR goes up as the square of the radius.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > To: Dr. Resonance
 > I have already understood (to some degree) the information you just
 > posted.
 > You seem to have missed what I was asking.
 > I know 4.5:1 works very well.  Since this is true I could then use my
 > 15KV 60Ma NST, give it a SRSG and a MC of .028 micro farads.  Then my
 > optimal coil height would be 9" tall right?  Providing I use a secondary
 > dia. of 2" I would still be in the 4.5:1 ratio and poof I should fall
 > into a good rule of thumb for my coil height.  I got it!  Thanx!
 >
 > Ok that was not meant to be sarcastic.  I was trying to show you that
 > the ratio was not my question as stated in the original question.  There
 > were actually a few questions I had.  but in reference to the one you
 > answered I was aiming somewhere else.
 >
 > Assuming I use your recommended 4.5:1 ratio.  What is a good height to
 > use based on the anticipated arc length?  Obviously the 9" tall coil
 > might have some problems if say 50" arcs were created.
 >
 > The question is based on a particular anticipated arc length, what is a
 > good rule of thumb to decide on the HEIGHT of the coil?
 >
 > After I get this under my belt ill re ask the other questions.
 > Thanx
 >
 > And again I do not mean to sound sarcastic just trying to make a point
 > in order to address my real question.
 >
 > Luke Galyan
 > Bluu-at-cox-dot-net
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Tuesday, January 13, 2004 9:01 PM
 > To: tesla-at-pupman-dot-com
 > Subject: Re: Secondary size
 >
 > 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
 >   >
 >   >
 >   >
 >   >
 >
 >
 >