Re: NST Max Ratings and Mains Resonance (fwd)

To: tesla-at-pupman-dot-com
Subject: Re: NST Max Ratings and Mains Resonance (fwd)
From: Tesla List <mod1-at-pupman-dot-com>
Date: Sat, 14 Feb 1998 17:11:23 -0700 (MST)
Approved: mod1-at-pupman-dot-com

---------- Forwarded message ----------
Date: Fri, 13 Feb 1998 20:09:58 -0800
From: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: NST Max Ratings and Mains Resonance (fwd)

Thomas McGahee wrote:

> I am concerned about toasting my NST's delicate
> windings.  Is there a way to calculate what the maximum secondary current
> from my NST is, knowing that it is resonant with my .01 uF cap?  Is there any
> way to de-tune this resonance, short of changing cap value or different NST's?

It seems to me that the worst case would be resonance for many cycles without the
gap firing.
The only limitation would be the series resistance of the secondary wire added to the 
resistances that you put in series, with the full open-circuit voltage over them.
Some detuning can limit this current , that will always be (peak or RMS values):

Imax=Vopen/sqrt(Rseries^2+(2*pi*60*Lseries-1/(2*pi*60*Cprim))^2)

Rseries can include also the resistance of the primary wire multiplied by the
square of the voltage transformation ratio, if this is significant.

Antonio Carlos M. de Queiroz
mailto:acmq-at-compuland-dot-com.br
http://www.coe.ufrj.br/~acmq