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Hi Fred, You may be right. Some anecdotal reports have indicated that the top of the transformer was partially blown off the unit. And there is indeed a distinct flash (and a muffled bang) accompanied by orange and yellow fireball just before the fuse goes. "Low voltage" (480 and 600 volt) power is very nasty stuff indeed, especially dueing arcing faults. At very high currents (~50 kA), LV arcs can exceed 2 meters (79 inches) in length. At high currents, magnetic forces (which scale to the square of the current) tend to move the arc very rapidly along (and away from) the electodes, helping to spread out the region of damage. I do have some other videos that I'll be adding when I get some time. We're currently getting prepared to do another run of Lichtenberg Figures in November, so much of my time is now being devoted to preparing specimens, fixturing, and discharge tooling. Best wishes, Bert
: Hi,
: First off, anal me, fascinated with the Florida substation video found
: something that maybe we didn't see. The transformer forcebly explodes
: before the expulsion fuse opens. Watch the portion of the transformer's
: tank, facing the camera. Just as the fire starts, behind the transformer
: in the oil-mist, and begins to wrap around, the tank facing the camera
: blows open with a bang, easily heard above the arcing fault and just
: before the fire hides the transformer and the fuse blows. Watch...it
: really does blow open with a very bright white-orange flash before the
: fire gets to it. I have watched this over and over again, definately the
: transformer blows open before power is cut, possibly its blowing open is
: what opens the big hV fuse.
: I have had electrical worker friends who have had large steel tools
: vaporized in their gloved hands when they accidently hit another phase in
: a 480V system. Yeah, that is major amperage. As you noted, protective
: suits must be worn nowadaze. This past summer, we were losing our power
: here, due to an unknown short within the building. When the electrician
: came to simply reclose the 480V main circuit breaker, he first had to get
: into his 'space-suit', just to push-closed the plastic switch on the front
: of the closed case. I can easily see why now, watching your video. An arc
: inside there would have instantly vaporized the metal case-door, exposing
: the worker to the 480 volt arc! Anyhow, the short turned out to be a
: ventilator motor burning out.
: You can definately see the bright blue-green arc persist in that wooden
: cabinet for the entire time the circuit was energized. Wonder how far out
: you could draw a low-voltage, mega-amperage arc like that.
: Awesome! Keep adding more video/photos!
: Thanks,
: Fred
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