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Re: NST's ARE ALL DEADLY !!!!!!!!
Hi:
I have just remembered something: The core of a transformer has
some hysteresis (or "memory"), and if a change in the magnetic
field in the core occurs, a voltage is induced in the windings.
A possible reason for these shocks taken from unpowered NSTs
can be a sudden change in the magnetization of the core. Maybe
for mechanical reasons (don't people report these shocks when
moving the NSTs?). Changes in magnetization of iron can be caused
also by induced AC fields. This effect was once used in the
magnetic RF detectors used by Marconi. If one touches the leads
of a transformer with a magnetized core, the induced current
in the secondary windings (coming from the power lines, or from
nearby RF sources) may be enough to trigger a change in the
magnetization, producing a shock.
A possible test for this: Pass some DC current through the
primary of an NST, decreasing it slowly, to force a magnetization
of the core. Connect then a small neon lamp across the secondary,
and connect the secondary terminals to antennas (long wires), or
one to ground and other to an antenna.
Antonio Carlos M. de Queiroz