Re: NST's ARE ALL DEADLY !!!!!!!!

To: tesla-at-pupman-dot-com
Subject: Re: NST's ARE ALL DEADLY !!!!!!!!
From: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 06 Mar 2000 12:46:38 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Mark, all,

Original Poster: "Mark Broker" <broker-at-uwplatt.edu>
>True, an inductor stores energy via a changing magnetic field,
>and trys to keep current flowing.  What is being overlooked is
>the iron core in an NST.  Iron is ferromagnetic, and has some
> incredibly unique magnetic properties.  One of these is to
>intensify the magnetic field (which is why it's used in xformers).
>Another is that it retains a magnetic field (called history). When
>the field slowly diminishes after shorting the NST, it "charges"
>up the inductive transformer windings.  Current cannot flow
>since there is no conductive path, so a charge is built up on the
>terminals.  When you touch the terminals, you dissipate the built
>up charge, and zap!

Interesting explanation, but there are several points, which I would
like to state, why "I" think this can´t be:

- Xformers are made of silicon steel. This has a very high resistance
  to (residual) magnetization.

- Xformers are made of laminations. This is done to minimize eddy
  losses and also to prevent magnetization. A magnetic core is
  very lossy.

- A current can ONLY be induced into a coil of wire in a changing
  magnetic field. If you hold a magnet near a coil, there will be NO
  current induced in the coil. If you start moving the magnet (or the
  coil), then you will get induction currents. This isn´t the case in a
  xformer core holding residual magnetism (The M-field doesn´t
  change direction).

- An inductor stores energy in the form J=0.5*L*I^2. If you have no
  current flow (a must for the above equation), you cannot store
  energy in the inductor. When you short an xformer, so that current
  can flow and then break this short, the inductor tries to keep the
  current flow constant. As you break the connection, the resistance
  rises towards infinity, so the inductor tries to compensate for this
  by raising the voltage (therefore keeping, or rather trying to keep,
  the current flow constant). Of course, it will never reach infinity,
  but it does provide quite a jolt, BUT only if there was a current
  flowing before hand.

Coiler greets from Germany,
Reinhard