*To*: tesla@xxxxxxxxxx*Subject*: Re: [TCML] Tesla Coil parameters list like Tesla Map software (i.e. spark length, secondary height, # of NSTs)?*From*: Futuret via Tesla <tesla@xxxxxxxxxx>*Date*: Mon, 6 Apr 2015 21:45:48 -0400*Delivered-to*: teslaarchive@xxxxxxxxxx*Delivered-to*: tesla@xxxxxxxxxx*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20140625; t=1428371149; bh=87X1y+BPPJG5Po99PjlH85Fn9K5kXpB97byuOVf1XyQ=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=pE6c0APWX4Nhv8hZWMLCvYFwx2fhe+HU5L+nRP3CArEiQ5c6oIPyDdb0AN+OBmlOg iIZ0AbCHCY8/kepEhP5wRF136KToU3Mfnun7Gq4N3r0TVUNVTUHfUxqQZw52QjFSHk mPF4n0XTuoh00wyjilvAv/TXUCrToXKgGzuufypo=*In-reply-to*: <CAL4hW5LyOYXAJgtSunvvsdwR5iwp3kQNR=FXH03HSZ3NiDdqNw@mail.gmail.com>*List-archive*: <http://www.pupman.com/pipermail/tesla/>*List-help*: <mailto:tesla-request@pupman.com?subject=help>*List-id*: Tesla Coil Mailing List <tesla.pupman.com>*List-post*: <mailto:tesla@pupman.com>*List-subscribe*: <http://www.pupman.com/mailman/listinfo/tesla>, <mailto:tesla-request@pupman.com?subject=subscribe>*List-unsubscribe*: <http://www.pupman.com/mailman/options/tesla>, <mailto:tesla-request@pupman.com?subject=unsubscribe>*Reply-to*: Futuret <futuret@xxxxxxx>, Tesla Coil Mailing List <tesla@xxxxxxxxxx>*Sender*: "Tesla" <tesla-bounces@xxxxxxxxxx>

I use the formula: spark length (inches) = 1.7*sqrt input power (watts) For example a coil that uses 1000 watts should produce a 53.7" spark. However this formula only works for very efficient coils. To get this sort of efficiency it's usually necessary to use a synch rotary spark gap at 120 bps, and a suitable LTR sized capacitor (for NST systems). Such a coil would work well with a 16" toroid. Toroid size tracks with spark length as given by the formula. Figure the toroid diameter should be about 0.3 times the calculated spark length. Or use the formula: toroid diameter (inches) = 0.5*sqrt input power (watts) Note that my formula uses a square rule for spark length vs. power input. The older idea of using a more linear relationship probably came about because many small old coils tended to be inefficient and therefore gave a false impression. The toroid formula will also only work right for an efficient coil. For example my TT-42 coil produces a 42" spark from an old "robust" 12/30 NST. The system draws about 800 Watts. The formula suggests 48" sparks, but I only get 42". However I have to crank up the input power using a 140V output variac to get the 42" spark, so the NST is probably saturating some at that point, and becoming less efficient. NST's can draw a lot more than their rated power in a Tesla coil running at 120bps. Over-volting them also makes them draw more power. Your 6" x 25" toroid should be able to produce 80" sparks (assuming a suitable Tesla coil design and power input. I don't think going to an 8" toroid will help your coil very much. There must be something else limiting your spark length. John -----Original Message----- From: Timothy Gilmore <tdg8934@xxxxxxxxx> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> Sent: Mon, Apr 6, 2015 8:09 pm Subject: Re: [TCML] Tesla Coil parameters list like Tesla Map software (i.e. spark length, secondary height, # of NSTs)? I found Jeff Pennoyer's site: http://www.webring.org/l/rd?ring=teslaring;id=107;url=http%3A%2F%2Fhome%2Ecomcast%2Enet%2F%7Epennoyer%2FJeffPage%2Ehtml At the bottom there is this list which falls in line with what I was looking for on spark length: APPROXIMATE SPARK LENGTH VRS POWER INPUT CHART SPARK LENGTH POWER INPUT 6 - 8 INCHES 300 W 8 - 12 INCHES 500 W 12 - 18 INCHES 700 W 15 - 20 INCHES 1000 W 18 - 24 INCHES 1200 W 24 - 30 INCHES 1500 W 30 - 36 INCHES 2000 W 36 - 45 INCHES 2500 W 45 - 56 INCHES 3000 W 56 - 64 INCHES 3500 W 64 - 72 INCHES 4000 W 72 - 80 INCHES 4500 W 80 - 90 INCHES 5000 W So using (2) 15kv 60mA NST provides about 1850 W. I am getting at least 36 inches and many times 48 inches or more of sparks from my 6"x25" toroid: _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla

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