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surge current of wires

Thread starter #1
Hello,

I would like to know if there is a chart that lists the maximum surge current of AWG wires. I am close to finishing my 4000 Joule 1600V capacitor defibrillator and would be inconvenienced if the wires explode/melt away.

-Thanks
 

Pommie

Well-Known Member
Most Helpful Member
#3
OK, I'll go along with the joke. A 1 thousandth of an inch diameter wire will easily carry 4000 joules without exploding or melting away.

Now ask a sensible question.

Mike.
 

tcmtech

Banned
Most Helpful Member
#8
Do you know the estimated discharge time? A joule is one watt second. If you dump it all in one second that the same as a 14.4 mega watt load at 1600 volts or about 9000 amps for one second.

Two 4/0 welding cables can take that kind of burst. they can hold a continuous duty 1000 amp submerged arc welder without trouble. Even with 20 KA peaks I doubt you would bother them one bit.
 
#9
Do you know the estimated discharge time? A joule is one watt second. If you dump it all in one second that the same as a 14.4 mega watt load at 1600 volts or about 9000 amps for one second.

Two 4/0 welding cables can take that kind of burst. they can hold a continuous duty 1000 amp submerged arc welder without trouble. Even with 20 KA peaks I doubt you would bother them one bit.
Cor!...some firework display if you shorted the leads... :)
 
#12
I hate meausing cable in AWG or SWG. Cross-sectional area mm² is much easier to understand.

So you're building a defibrillator; how do you plan to spend in getting it approved?
 

tcmtech

Banned
Most Helpful Member
#13
At 4000 joules and 1600 volts its not a defibrillator. Its a vaporizer!:eek::D
Still, I would play with it!
 
#14
Onderdonk vs. Preece

16 gauge copper wire: Tmelt = 1083, Area = 2581 circ mil, Time = 5 sec, Tamb = 25

E= Area in CM
B = Tmelt - Tamb in deg. C
D = 234-Tambient in deg. C
T= time in seconds.
So, E = 2581, B= 1058, D=209, T=5
Then
Ifuse = E* SQRT {<LOG[(B/D)+1]>/(T*33)}
Ifuse = 2581* SQRT {<LOG[(1058/210)+1]>/165}
Ifuse = 2581* SQRT {<LOG(6.04)>/165}
Ifuse = 2581* SQRT {0.781/165}
Ifuse = 2581* SQRT {.00473}
Ifuse = 2581* 0.0688
Ifuse = 178A
 
Last edited:
#15
So that's 178A for 5 seconds to hit the melting temp?
 
Last edited:
#16
What about the insulation?

The plastic/rubber insulation will burn up long before the conductor vaporises.
 
#17
Jeez....I have a Tens machine for pain relief and thats enough for me....178Amps...boy you can weld with less than that....
 

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