Re: OLTC update - Poor seconadry Q

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

Original poster: "Kurt Schraner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <k.schraner-at-datacomm.ch>

Hi Terry,

with highest interest I follow the development of the OLTC from the 
beginning, just by lurking. Great what you make happen there, letting us 
take part! Regarding the secondary Q problem, just thinking out loud: 
Might we benefit from something, along the lines of Jeff Behary's 
rediscovery of Tesla's multilayer pancake secondary coils ? Jeff is 
taking reference to

Tesla's Patent No.593,138; 2.Nov.1987

which is not currently at my disposition. Jeff's development may be 
clicked at his website:

http://www.electrotherapymuseum-dot-com

...more specifically at:
http://electrotherapymuseum-dot-com/Pancake1/

...and for the coil winding process:
http://www.electrotherapymuseum-dot-com/Details/index.htm

While there are probably better ones, here is a formula for short 
multilayer pancake air coils:

L[mH] = K*N^2*(Da/2)*10^-5

with Da = outer diameter [cm]
     Di = inner diameter [cm]
     x = Di/Da;     0.1 < x < 0.9
     length << Da  (short coil!)

     K=7.1801*x^3 - 5.6587*x^2 + 3.748*x + 0.5068

My hope is, getting better Q high inductance coils, while keeping size 
and weight within a reasonable range, relative to the OLTC needs. The 
winding experience with old style induction coils also might provide 
interesting alternatives to a pure solenoid secondary. Vacuum 
impregnation might be needed, but also is easier with smaller coils.

Cheers,
               Kurt