Anyone ever see one of these? I visited an electrical collector / hoarder in south central Iowa (about 15 years ago I think?) and this was one of the favorite items in his collection - this device MECHANICALLY rectified high voltage AC into DC! On one side were 2 shoes connected to the AC source, and on the other, 2 other shoes collected the pulsed DC output. A synchronous motor spinning at 3600 RPM rotated a spindle with 2 arms that carried an electrode in each, arcs traversing from each input shoe through the spindle to the output shoe at the appropriate time. The arcing made for a hissing noise even I could hear. I imagine most were disposed of a long time ago just because of the sheer amount of RFI and ozone these things must have put out! In case you're wondering about the various jumper wires, the collector DID have it rigged for show - using various resistances on top to drop the voltage down enough to light a neon tube (up near the ceiling).