: --Previous Message--
: Hi Bert,
: I believe that this is the link! Holy Moly! That arc is racing by! Now we
: know what a Jacobs ladder looks like when there are several hundred amps
: behind it!!!
: Hi Fred,
: Here's a clip you might also enjoy from Germany. It uses 3kV at about 500A
: to create a rotating "jacobs ladder" between two circular metal
: rails. The rails have a slit so that they are not continuous (to prevent
: arc forces from otherwise being balanced about half way through the loop).
: The higher the fault current, the stronger the Lorentz forces, and the
: more rapidly the arc travels.
: This effect is actually put to good use within some high current HV vacuum
: contactors that need to safely interrupt extremely high fault currents.
: When the contacts part, magnetic forces cause the roots of the vacuum arc
: (i.e., the very hot cathode and anode spots) to rapidly sweep across the
: electrodes in a circular path instead of staying in one place. Rotating
: the high current arc helps to extend the life of the electrodes by
: reducing electrode evaporation. The switch would rapidly fail if the arc
: stayed in one place for any appreciable length of time.
: In this clip, it looks like they are actually tapping power right off a
: pair of phases in a small substation! I really can't see any power company
: in the US letting someone do a "demo" like this - too much risk
: for equipment damage. Anyway, here's the URL:
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