Strange Short Circuit

nsaspook

Joined Aug 27, 2009
9,435
60VDC @ 5A can easily sustain a stable arc. The pits on the arcing conductor are anode and cathode melting pools of the ionized metal (the bright arc seems to be from the plug plating being vaporized) into charged ions and electrons.
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Thread Starter

NatGazer

Joined Dec 23, 2020
18
60VDC @ 5A can easily sustain a stable arc. The pits on the arcing conductor are anode and cathode melting pools of the ionized metal (the bright arc seems to be from the plug plating being vaporized) into charged ions and electrons.
View attachment 257431
I had no idea that 60V were enough to start an arc in the air, but now I'm starting to understand that's not so hard to happen in low voltages
 

MisterBill2

Joined Jan 23, 2018
11,556
The arc was never "sustained" beyond a second or two, and so it may well be that the supply overload protection did not operate that fast. In addition, there is usually a fair amount of capacitance in the cupply circuit beyond the current sensing system. Besides all of that, 5 A x 60V =300 watts, and that much power in a single point can easily create a large amount of heat, as the evaporated metal arc shows us. Power density is what helps create such impressive arcs, and is a major portion of the arc-flash hazard. The metal vapor can deliver a lot of heat energy.
 

shortbus

Joined Sep 30, 2009
9,320
What do you think is the voltage in Arc Welding?
Or those High Powered Carbon Arc searchlights?
Or those (ancient) Film Projectors in a Movie Hall?
Add EDM(electrical discharge machining) to the list. Most any thing you buy made from plastic, the mold used to make that part was machined by the EDM method. A graphite or copper electrode in that shape disintegrating hard steel to make the mold. At around 60V DC.
 

MisterBill2

Joined Jan 23, 2018
11,556
Carbon arc metal cutting rods should be available at places that sell welding supplies. They have a very big advantage of having a copper plated body so that most of the carbon rod does not get so very hot. Also, they are much easier to grip well and much stronger, avoiding breakage.
 
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