Re: Tesla humor and I hope I get this right this time!

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi Garry,

>At 07:54 PM 8/25/00 -0700, you wrote: 
>There once was a man named Birquette.
>Whose Tesla hobby put him in debt.
>While adjusting his gap, he got a large zap 
>and now he's a charcoal bricquette!
> 
>Now the question. Yep, I made up the above limmerick

Good, you sound happier :-))

> 
>I keep mis-stating the thickness of the polyethelene between my stack cap by 
>mentioning the thickness of an individual sheet instead of the total 
>thickness. Well, this makes the eighth try and if I get it wrong this time, 
>I guess I don't deserve the answer.
> 
>Each plate is separated by four .012" sheets for a total of .048 thickness. 
>I hope I got the decimal place in the right place.

That sounds great!  0.48 inches will stand off 57600 volts which is over
three times the peak voltage which is just right for these caps.  It will
probably be large enough that heat is not a problem.

> 
>The area of overlap on each plate equals 26 square inches.

The formula is:

C = (0.2235 x K x A x (N-1)) / D

Where:
C = The capacitance in pF
K = The dielectric constant
A = Area of a single plate overlap in square inches
N = The number of plates
D = The distance between plates in inches.

Ok were set:

For polyethylene, K = 2.3, A = 26, N = ??, D = 0.048, C = 10nF*

*Below you want 10nF = 10000pF = 0.010uF   We use 10000 for this equation.

We can "fix" the above equation to read:

N = ((C x D) / (0.2235 x K x A)) + 1

So..... N = 37 plates.

> 
>The transformer is a 12/30 NST. When I try to calculate the value of the 
>cap, and compare it to what I see in some plans I have, the figures don't 
>make sense.

I can't see the plans, but everyone has their own ideas about this stuff.
In the last few years, there is much better agreement.  But if the plans
are more than 4 years old, who knows what they were thinking.

An LTR cap size is:

C = I / (2 x pi x F x V) x 1.5

Where:

C = the resonant capacitance value in Farads
I = The transformers current rating in amps RMS
pi = 3.14159...
F = The line frequency (50 or 60 Hz)
V = The transformers rated voltage (volts RMS)

So:

0.030 / (2 x 3.14159 x 60 x 12000 x 1.5  =  9.947nF

We'll call that 10nF.

> 
>What I need is a reccommendation on the number of plates I should use in 
>this cap for a LTR cap. I guess I want between .80pF to 1.00pf or is that 
>supposed to be uF?

37 plates for 10nF.

m = 0.001  =  10^-3
u = 0.000001  =  10^-6
n = 0.000000001  =  10^-9
p = 0.000000000001  =  10^-12

> 
>According to an online wintesla that I lost the link to, my secondary 
>resonates at 450mhz?? It's a thick wall OD of about 3.5 inches the wound 
>area is 24" long with #29 wire. 

I would guess closer to 250kHz once you add the top terminal.

> 
>--
> 
>How do you know your neighbor is a Tesla maniac?
> 
>He has curly hair and he's swedish.
>You find him winding a primary around his house.
>There is a large toriod on his chimney.
>The primary is attached to a lighting rod!
>All the telephone poles on the block are sanded smoothe and varnished.
>He has a program to calculate the k rating of tennis shoes!
>If RF begins to interfere with is TV, the TV goes out the door!
>He doesn't know the size of his wedding ring but he does know it's inductance!
> 
>

Oh yes, you are happy!  Or you have gone nuts like the rest of us ;-))

Cheers,

	Terry