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Re: [TCML] John Freau's streamer length equation

A large enough toroid diameter is needed to get the arcs to reach the full length.  Arcs tend to not be able to reach beyond 4 times the toroid diameter no matterhow much power you use.  (unless you use huge power such as in Bob Golka'sproject Tesla... something like that).  Also sometimes the VA input is a lot higherthan the wattage depending on the power factor.
John Freau

-----Original Message-----
From: Terry Oxandale <Toxandale@xxxxxxx>
To: Tesla Coil List <tesla@xxxxxxxxxx>
Sent: Mon, Apr 13, 2020 12:23 pm
Subject: Re: [TCML] John Freau's streamer length equation

I hope so (laughing). At 4500 input, I should be getting nearly 10' arcs, which I'm a long way from that (best was 82" point-to-point).

-----Original Message-----
From: Tesla <tesla-bounces@xxxxxxxxxx> On Behalf Of Steve White
Sent: Monday, April 13, 2020 9:39 AM
To: Tesla Coil List <tesla@xxxxxxxxxx>
Subject: **External Email** [TCML] John Freau's streamer length equation

I was wondering if John Freau's empirical streamer length equation applies equally well to both SGTCs and DRSSTCs? It seems to me that it would since both SGTCs and DRSSTCs both operate on the principal of feeding a rapidly repeating stream of CW pulses into the primary coil.

A related question involves how to measure the streamer length as predicted by the John Freau equation. Do you mentally straighten out the streamer removing all the bends and curves or do you just measure the straight-line length from start to finish with a straight line cutting through the bends and curves? My thinking is that you mentally straighten out the bends and curves into a straight line before making the measurement.

Here is John Freau's equation for spark gap coils for reference:

Length = 1.7 sqrt(input power)

where Length is in inches and input power is in watts.

Steve White
Cedar Rapids, Iowa

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