Re: ball topload

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

The breakout voltage for 11 inch radius is about 840kV.

The capacitance of the sphere is 31pF.  But a real system will be around 50+pF.

The energy needed to charge that capacitance to 840kV is 17.64 joules.  For 
a 120BPS system operating at 50% efficiency, we get 4.2kW input just to get 
it to the breakout point!

You may need more power for good streamer growth (but I am just 
guessing.  Would have to compare these numbers to normal coils).

So about 5kVA minimum.  I think once it broke out you would be able to 
sustain the streamer without too much more power.  10kVA should certainly 
do well.

Note that the 840kV breakout is really high compared to normal coils.  The 
secondary coil or other things may want to breakout before the top sphere.

About 4 years ago someone (Gary Weaver?)* had a 3 foot buoy on a 
coil.  They had to use a breakout point.

http://bhs.broo.k12.wv.us/homepage/chip/current/gweaver/map.html

http://bhs.broo.k12.wv.us/homepage/chip/current/gweaver/TC10-1.JPG

He has 240VAC at 40 amps for 9.6kVA.

Strange how I can remember these things *:-))

Cheers,

         Terry


At 08:54 AM 10/23/2003, you wrote:
>Anyone know what would be a good kva input (to get single arcs) for a 22" 
>sphere?