Re: [TCML] NST coil question

[Quarkster <quarkster@xxxxxxx>]

Andrew -

As usual, selection of components depends on what you are trying to accomplish. A larger toroid has the potential to generate a smaller number of longer streamers, while a smaller toroid may generate multiple but slightly shorter simultaneous streamers. What visual effect do you prefer?

The choice of MMC value depends on several factors, including what type of spark gap you intend to use, how accurately you can set your safety gap, and if you have the self-control to leave the safety gap set at a reasonable breakdown voltage.

The "resonant" tank cap value for a 12/30 NST is .0065uF. However, a resonant cap value has the risk of resonating with ("ringing up") the inductance of the NST secondary, resulting in extremely high voltages. Unless your tank circuit is protected by a correctly-adjusted safety gap, both the NST and the tank capacitor may be destroyed due to insulation breakdown.

A "safer" approach to avoid the potential for destructive ring-up is to use a capacitor value that is larger or smaller than the resonant value. Best performance is usually obtained with a larger-than-resonant ("LTR") capacitor value. For a static spark gap, the LTR value for a 12/30 NST is around .01uF. If you are using a synchronous rotary spark gap, a value around .017uF is appropriate. In any case, make sure that the primary circuit is equipped with a properly adjusted safety gap.

Regards,
Herr Zapp


--- On Mon, 5/18/09, Andrew Robinson <teslamad@xxxxxxx> wrote:
From: Andrew Robinson <teslamad@xxxxxxx>
Subject: [TCML] NST coil question
To: tesla@xxxxxxxxxx
Date: Monday, May 18, 2009, 11:21 PM

For a 12kv 30ma coil with a secondary approximately 4" x 22"
(windings), should I use a 3" x 12" spun toroid, or 4.5" x
18" spun toroid?

Also, when I run my calculations, for a MMC cap with a 12/30 NST my capacitor
should be .0066 uF, but I keep hearing others suggest .0093 uF?

See my calculations (2003 word document) here:
http://host.atomiklan.com/tesla/Noname.doc
<http://host.atomiklan.com/tesla/Noname.doc>

Thanks for the help... Its been awhile since i've done this stuff.

Regards,
Andrew
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla