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Re: NST Max Ratings and Mains Resonance (fwd)





---------- Forwarded message ----------
Date: Sat, 14 Feb 1998 11:24:38 -0500
From: "Alfred C. Erpel" <aerpel-at-op-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: NST Max Ratings and Mains Resonance (fwd)


-----Original Message-----
From: Tesla List +ADw-tesla+AEA-pupman-dot-com+AD4-
To: tesla+AEA-pupman-dot-com +ADw-tesla+AEA-pupman-dot-com+AD4-
Date: Friday, February 13, 1998 12:56 AM
Subject: NST Max Ratings and Mains Resonance (fwd)


+AD4-
+AD4-
+AD4----------- Forwarded message ----------
+AD4-Date: Thu, 12 Feb 1998 15:54:09 -0500
+AD4-From: Thomas McGahee +ADw-tom+AF8-mcgahee+AEA-sigmais-dot-com+AD4-
+AD4-To: Tesla List +ADw-tesla+AEA-pupman-dot-com+AD4-
+AD4-Cc: MALCOLM+AEA-directorate.wnp.ac.nz, Wysock+AEA-courier8.aero-dot-org
+AD4-Subject: NST Max Ratings and Mains Resonance
+AD4-
+AD4-Bill, Malcolm, and other interested coilers,
+AD4-Besides the resonant rise that Malcolm mentions, there is also 
+AD4-the fact that when the main cap and the transformer are set to
+AD4-resonate at the mains frequency, the transformer is capable
+AD4-of providing current levels that are several times the usual 
+AD4-'current-limited' value. If the wire in the secondary is too
+AD4-thin, then you can actually burn out the secondary winding
+AD4-under these mains-resonant conditions.
+AD4-
+AD4-Thus, with the proper resonant conditions a 15KV 60 MA
+AD4-NST can charge the mains cap up to voltages in excess of
+AD4-40KV, and at a rate that is much greater than the 60 MA
+AD4-rating would suggest. Note that both the extra voltage and
+AD4-extra current can contribute to the NST failing prematurely.
+AD4-
+AD4-Hope this helps.
+AD4-Fr. Tom McGahee


+ACoAKgAqACoAKg- big snip +ACoAKgAqACoAKg-

    Hello,

    It is my understanding that in a series resonant circuit, the
capacitive reactance and inductive reactance exactly cancel out, leaving
only the pure resistance (ohms) as the total circuit impedance.
Therefore,(at resonance) the current (I) flowing in the circuit is
determined by I+AD0-E/R where E +AD0- input voltage (to the series
resonant circuit) and R +AD0- ohms resistance of the circuit. 

    My point is, I can see how power (EI) is increased in an inductive
circuit because voltage is increased (and of equal value) measured across
the capacitor and inductor, but the current (I) flowing in the circuit has
not changed.
    What resonant conditions allow/cause an increased current flow?

Regards,
Alfred Erpel