[TCML] Re Electrode diameter

[David Rieben]

Hi Bart, Phillip,

I use 3/8" diameter flying electrodes and 1/2" diametered
stationary electrodes (all pure tungsten) in the ARSG of my 
large Tesla system: http://www.teslauniverse.com/members/drieben/
The electrodes were originally tungsten carbide drilling blanks
but I have since changed them over to 99.95% pure tungsten.
Expensive? Yes (I probably have over $150 in the tungsten
alone) but still well worth it in my humble opinion. Also, you
will have to excuse the outdatedness of this website as none 
of the still images have been updated in over two years now!
I'm just not much of a website guru ;^/ BTW, I am able to
run up to 20 kVA with this setup and the electrodes stay
at a reasonable temperature (there is no visible incandes-
cence of any of the electrode surfaces after a long, high
powered run) ;^) Quenching does start to become a real
issue at these kinds of power levels, though, as I can de-
tect a "popping" sound accomapanied by a visible flaming
yellowish plasma around the spark(s) of the RSG above
the intense noise levels of the output spark streamers! I have
recently added another pair of stationary 1/2" diameter sta-
tionary electrodes to the ARSG so that I now have two 
pair of stationary electrodes placed 180 degrees apart on
opposite sides of the rotary disc to further commutate the 
spark gap's heating energy. I haven't yet had a chance to fire 
it at high power since this recent modification as firing this 
beast requires dragging it onto the driveway ;^()

David


----- Original Message ----- 
From: "Barton B. Anderson" <bartb at classictesla.com>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Sunday, December 02, 2007 11:50 AM
Subject: Re: [TCML] Re Electrode diameter


> Hi Phillip,
> 
> If you have the 1/2" tungsten, I would recommend using them, especially 
> on the stationary side. Everything heats up with enough power and the 
> larger electrodes will handle the power better. I use 3/8" tungsten, but 
> if I had 1/2" I would certainly use them.
> 
> Take care,
> Bart
> 
> Phillip Strauss wrote:
>> Hi All,
>> I'm building a 12" diam. secondary SRSG coil running at 10Kv, 7KVa, 
>> 50Hz and 100bps. Motor speed is 3000rpm, rotor 12" diam G10, two 
>> flying electrodes at 11" diameter and tank capacitance 0.15uF.,
>> I have a selection of Tungsten electrodes, both 1/4" and 1/2" diam and 
>> have a choice of either two or four fixed gaps in heavy brass. Is 1/4" 
>> diam adequate to contain the heat
>> or is 1/2" better perhaps to aid regular firing albeit increasing the 
>> dwell. Should the electrode gaps be minimal ( without risk of contact 
>> of course) or is there  an optimum distance,
>> again to slightly reduce the dwell time. I appreciate that the 
>> relatively low input voltage limits experimentation in this last regard,
>> Any help greatly appreciated,
>> Regards,
>> Phillip.