Dual CPU nodes?

Alan Scheinine scheinin at crs4.it
Tue Oct 22 02:44:31 PDT 2002

Karen Shaeffer wrote, "The bracelet was a closed circuit that was          
enclosing Magnetic flux from the power line."
But there should not be any external magnetic flux.  If one wants to
know the current on the line without cutting the wire to insert an
amp meter, then one can place a magnetic sensor around the wire.
But it is necessary to split the conductor pair because the external
magnetic flux of a pair of wires with current in the opposite direction
is zero a short distance from the wire.  The same probably applies the
the set of wires in the power run.  Moreover, if one want to take in
hand a College Physics text, it would be useful to make an order
of magnitude estimate of the force, it is probably small.  The place
where you would find a large amount of stored magnetic energy is in
a transformer.  For example, if a transformer is underdesigned with
respect to the actual current, you can hear/feel the surrounding case
vibrate because the iron core is saturated during part of the cycle.
Rather than magnetic flux from a wire, one might wonder if there was
a transformer or an inductor (a ballast) that was responsible for
the effect on the bracelet.  Another possibility is the following.
The energy in a tranformer must dissapate, the result is that if a
circuit breaks abruptly then the transformer raises the voltage to
maintain the current.  However, the magnetic flux depends on the
current and though the voltage would rise at the break, the current
would still decrease monotonically.  (Opps, I should add, the
induced current depends on the change of magnetic field, which could
be due to the change of the current.)  In any case, it seems likely
to me that an unpaired conductor and a large transformer need to
enter into the story.
Alan Scheinine

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