Re: Recent power arc experiments

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "boris petkovic by way of Terry Fritz <twftesla-at-uswest-dot-net>" <petkovic7-at-yahoo-dot-com>



 
> First, let me say that this is an ultra cool
> experiment!!
> 
> I think I know why the resistors stayed cool!
> 
> My testing has shown that arcs are about 220 kohm
> plus 1pF per foot of arc
> impedance.  The nine 1500 ohm resistors are only
> 13.5 kohms of resistance.
> Thus, most of the heat energy (95%) was being
> dissipated in the arc rather
> than the resistors.

Hi Terry,


I would defintely agree with you in case the resistors
were not grounded .But they were grounded ;thus
allowing higher current bursts  where all avilable 
energy was dissipated in some sort of short circuiting
of secondary structure by 13.5 kohm + power arc
impedance .

So this is the case:
 __
(__)       gap     ----- Resistors ----l  
  (                                              I   
  (                                              I    
          
  (                                              I
  (                                              I
  (                                            _I_
------                                      ground


With use of decent sized top electrode and without any
resistors included in arc way, most of the supplied
energy would be released in short lasting current
burst (usually houndreds of amps and times bellow
microsecond).This scenario is quite different than
usual corona modus operandi. 
I would think that part of energy is still dissipated
during voltage ring up time interval where corona
model can be used ,but I guess it shouldn't be as
large as part of energy consumed during short burst
transients.
Indeed,13.5 k  should reduce peak currents to about 30
A here,and new arc impedance situation lays somewhere
between corona modus operandi and  short circuiting
condition.
Arc impedance should obey the rule higher current less
resistance,but how exactly characeteristic looks like
for every separate case one can only guess.

Regards,
Boris
  

    

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