RE: Arc length vs pwr

To: "'tesla-at-pupman-dot-com'" <tesla-at-pupman-dot-com>
Subject: RE: Arc length vs pwr
From: Dan Gowin <gowin-at-epic-1.nwscc.sea06.navy.mil>
Date: Tue, 1 Oct 1996 08:17:53 -0000


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From: 	Tesla List[SMTP:tesla-at-poodle.pupman-dot-com]
Sent: 	Saturday, September 28, 1996 5:25 PM
To: 	Tesla-list-subscribers-at-poodle.pupman-dot-com
Subject: 	Re: Arc length vs pwr

>From couturejh-at-worldnet.att-dot-netSat Sep 28 14:51:15 1996
Date: Sat, 28 Sep 1996 17:22:14 +0000
From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
To: tesla-at-pupman-dot-com
Subject: Re: Arc length vs pwr

At 04:25 AM 9/27/96 +0000, you wrote:
>From 100624.504-at-CompuServe.COMThu Sep 26 22:18:21 1996
>Date: 26 Sep 96 14:27:22 EDT
>From: Alan Sharp <100624.504-at-CompuServe.COM>
>To: Tesla List <tesla-at-poodle.pupman-dot-com>
>Subject: Re: Arc length vs pwr
>
>> Several years ago I went thru this process and published a graph in the
>>Tesla Coil Design Manual. The graph was made from data I had collected from
>>over three dozen coils built by myself and other coilers. The data was
>>converted by math regression into equations that could be made into graphs
>>and used by a computer.
>
>I'd be interested to know what spark lengths are achievable at say
>500W, 1KW, 2KW, 5KW and 10KW with 2 coil and magnifier systems.
>
>Arc length to grounded rods please - no fish stories.
>
>Give me something to aim at with the MOSFET's.
>
>Alan Sharp (UK)
>

Alan -

The TCD Manual graph shows typical Tesla coil spark lengths vs wattage as
follows: 

500 w/11 in, 1 KW/20 in, 2 KW/32 in, 5 KW/64 in, 10 KW/110 in

The graph is for classical coils only and the curve is non-linear. The spark
lengths are for horizontal sparks from a toroid to a ground point. I do not
have enough information presently available to make a meaningful graph for
magnifiers or tube and solid state Tesla coils. In the TCD Manual I
guesstimate that the theoretical spark length for magnifiers would be up to
about 1.5 times the classical coil length. However, I have not seen data to
indicate this is possible when rigid test comparisons are made.

Note that the spark lengths shown by the graph can vary greatly depending on
several factors. For example, spark lengths for the same wattage are greater
with pole transformers than for neons. Also, the spark lengths are increased
when the Tesla coil primary voltage and/or the secondary coil inductance are
increased, etc. These variables are taken into consideration by the JHCTES
computer program.

Hope this helps.

Jack Couture


Mr. Couture,
	This can't be correct. My current coil uses a 1KW  (9KV+120Ma)
neon sign transformer with .03 uF of tank capacitance. My secondary
is 4.5" dia with 937 turns of 24 AWG magnet wire. My secondary inductance
is 19.88988 MH. And my toriod capacity is about 12 pF. My Resonate
frequency is 252 KHZ and my max sustained spark length is 30". My max
strike distance measured is 35-36". Unless my neon is not shunting the
current correctly, there is something incorrect about these calculations.

D. Gowin