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Re: Reactance



On Sun, 2 Feb 1997, Tesla List wrote:

> > Subject: Reactance
> 
> Subscriber: bert.hickman-at-aquila-dot-com Sun Feb  2 17:41:49 1997
> Date: Sun, 02 Feb 1997 09:20:16 -0800
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>

<MAJOR SNIP>

> > X = 1/(2*Pi*F*L) for inductive reactance, where
> > X is on ohms
> > F is in Hz
> > L is in Henries
> 
> Not quite... This should instead be:
> 
>   X = 2*Pi*F*L  (i.e., X should increase with increasing F or L)
> 

Ah! now it works out... :-)

> Not quite... This should read 
> 
>        ____1____
>   X = (2*Pi*F*C)  (i.e. X should decrease with increasing F or C)
> 

Yup, that makes it fit better too...

<SNIP AGAIN>

> A few quick calculations to design the coil to be in the ballpark can
> save a LOT of grief later, and copper tubing and HV capacitors aren't
> free if you've made a seat of the pants "guess" that's wrong.

Exactly the reason why I'm learning to enjoy the maths. Better to 
calculate for cost-effectiveness! Get's very costly after having built 3 
coils without calculation...errghh...bad memories...

> Sounds like an excellent approach, and one that most experienced coilers
> follow. After building enough coils, I suppose one could get a real
> "feel" for what would work properly together... but a simple set of
> spreadsheet equations (like Ed Sonderman's nice Excel design tool) can
> save hours of work and many $ for inexperienced coilers!

Ok, I've got that, when I re-install WIN95 (cos it crashed, and not from 
running TC's nearby :-) ) I'll check out Ed's work....thanks for that..

> No flames today, Rodney... your approach should work just fine once you
> shake the bugs out of the equations. Check out Ed Sonderman's
> spreadsheet on the funet site - you'll like it! Good luck on your coil!
> 
> -- Bert H. --

Thanks Bert, much appreciated for your help...
I can see how the values work out when the equations are correct...next 
time I'll read them out of a book myself instead of getting someone to 
try and remember them for me... :-)

Thanks again,

Regards,
Rod.

an attempt at a humourous quote for the day -
"Who are the F.C.C. and why do they want my Tesla Coil?"