[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Primary coil configuration



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi John,

I personally measure the bang size sorta directly by scoping the firing voltage. It would be an interesting set of data to have a max bang size vs winding height. I'm planning on a bang size of 40J for my next coil, so we will see.

Gerry R.

Original poster: FutureT@xxxxxxx
In a message dated 4/21/06 4:38:26 PM Eastern Daylight Time, tesla@xxxxxxxxxx writes:


Is there any data on max bang size vs secondary coil size??  What
would be the most important secondary coil size parameter (height,
diameter, number of turns, etc)??


Gerry,

I think the most important factor is coil height, followed by diameter,
and finally number of turns.  At least if the height is sufficient
for the bang size, the coil won't self destruct.  Aspect ratio
can vary over some range without a tremendous difference in
spark length.  Usually rules of thumb are followed for these
various parameters.  Number of turns can also vary without a
tremendous difference in spark length, although I like to use
about 1200 to 1500 turns especially if the aspect ratio is
high.  Wider coils can tolerate fewer turns because the
greater width increases the inductance anyway.  To figure
out the largest allowable bang size for a given coil, one
can increase the power until the coil begins to self-destruct,
then back off the power some for a margin of safety as a first
step.  Next divide the power input by the break-rate to obtain
the approximate bang size (not considering losses).  This gives
the maximum ~bang size for the coil.  Theoretically the break
rate can be increased, thereby increasing the input power and
the spark length, and the coil should still survive.  This is
because the coil survival should depend more on the max
bang size than on the power input or spark length.  Has anyone
tried this?

John