Re: Secondary wire AWG

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

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

In a message dated 1/16/04 11:32:19 AM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:
Original poster: "Luke" <Bluu-at-cox-dot-net>

I know that the total number of turns is taken into consideration when
choosing the awg for the wire used on a secondary.
I have also seen that the currents can be high at the base of the
secondary.  That makes me think a larger wire size should be used to help
handle the currents.

Any input on what would be too small or too big for a wire size on a secondary?

Luke Galyan
Bluu-at-cox-dot-net

Hi Luke,
     Again, it is a balancing act. With thin wire you have higher 
inductance for a given length, which is good, but also higher I^2R losses 
or a short coil, prone to racing sparks and primary strikes, which is bad. 
Very thin wire is hard to handle and prone to breakage while winding. With 
thick wire, you have lower I^2R losses, which is good, but lower inductance 
unless you make the coil taller, which may lead to lower coupling and poor 
energy transfer, and a physically unstable size, which is bad. Thicker wire 
also costs more and weighs more. Bigger wire implies a bigger coil form 
which means more weight and cost.  As a "rule of thumb", a livable 
compromise is to use wire gauges in the 20s. Low 20s for higher power coils 
and upper 20s for lower power coils. This is only a good starting point. I 
have seen working coils wound with everything from #10 to #40.
     Time, space, money, weight, local availability, structural stability, 
and aesthetics are all limiting factors that are difficult to incorporate 
into a precise formula. Finding the limits means having the resources ($$$) 
to push coils to the point of failure, then pull back a little on the next 
ones.

Hope this helps,
Matt D.