RE: Secondary size

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

Original poster: "Luke" <Bluu-at-cox-dot-net> 

Ok lets say the break rate will be 120bps
The power input will be 900watts (15KV -at- 60mA)
The expected spark length is 50"
How does one choose a secondary height from that?
Please do not just tell me what height to make it.
I want to hear WHY.

thanx

Luke Galyan
Bluu-at-cox-dot-net

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, January 14, 2004 3:26 PM
To: tesla-at-pupman-dot-com
Subject: Re: Secondary size

Original poster: FutureT-at-aol-dot-com

In a message dated 1/14/04 10:08:16 AM Eastern Standard Time,
tesla-at-pupman-dot-com writes:

 >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?


Luke,

It depends on the breakrate and power input and expected
spark length.  At lower breakrates which involve a larger
"bang size", the coil must be taller than for higher breakrates
which involve a smaller bang size for a given power input and
spark length.

At 120 bps, I found it necessary to use a 23" secondary
winding height to obtain a 59" spark without coil breakdown
or racing sparks on the secondary.  At higher breakrates
the secondary can be somewhat shorter for the same spark
length.  The dimensions should be somewhat proportional
for larger and smaller coils also.

John