Tree branch on wires

you're tapping my oldest memory banks now.

when i was a kid had a next door neighbor hwo was a sort of Sorcerer's Apprentice, making Jacob's Ladders and the like.

I think you'll find the arc went up by simple convection like the smoke did. The ionized air is very hot...

there is a force on the charge that is moving through the arc, Q X Velocity (cross) B
but shouldn't that twist the arc parallel to conductors?
i didn't notice that in the video..

old jm

 

Tree branch "falls" on power lines? From nowhere on a relative wind-free day with cameras ready? Admit it, you threw it up there didn't you?

 

""""But this is AC, how does lorentz force apply to this when we have alternating B field."""

B alternates certainly, and so does Velocity (current in the arc is alternating )

i think you're right - if i remember how to cross vectors, the result also alternates direction hence nets to zero....... mumble mumble...c'mon old brain,,, V X B--- rotate V into B and result is direction a right hand thread would move?

was hoping youd reaffirm my old memory because i dont have my books handy. (visiting friends away from home)

am i right , my kind friend?

 

This old video shows what it looks like when transmission line phases arc.

https://www.youtube.com/watch?v=hIkNY5xjy5k

 

i think the Q V cross B forces are making the arc 'corkscrew"

and simple bouyancy of heated air is driving it upward

but i'm going from old memories here and need corroboration from freshman physics.

and yes Bassalisk that's what i was looking for..... step 1 toward that corroboration

memory - i can almost remember when i had one........

 

that last video is intentional opening of a disconnect switch in that yard. first second you can see it swing away.... that kind of switch cannot interrupt load current, but the simple charging current makes a plenty impressive arc.

so judging by lack of excitement by participants that video, the current was pretty small. i didnt notice molten metal falling...

 

Maybe I was your neighbor. I've still got my 9KV neon sign transformer.

 

power side of EE is to me more interesting than computers.

i honestly considered programming but decided it's more fun to magnetize iron by the ton than by the micron.

i was happy with DOS and QBASIC.


but that's just me.

old jim

EDIT Don keep those treasures. you never know when you'l influence somebody ! my life is richer for those memories of Mr Gaunt's garage ....