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Re: Breakdown voltages of toroids



Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:

 > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 > I assume you're figuring breakdown for when the Efield at any point on the
 > surface exceeds 31 kV/cm (or whatever number you used for the sphere)...
 > How do your sphere gap numbers compare to the tables?

I assumed a maximum electric field of 30 kV/cm.

I list below some results, comparing with part of a table that I
found at your site some time ago (for some reason, I could not find it
again today at your site):

One sphere grounded. Table values between (). Values in kV:
sphere diameter (cm): 5               10
gap spacing (cm):
0.5              14.3 (17.4)      15.0 (16.9)
1                26.3 (32)        28.6 (31.7)
1.5              36.0 (44.7)      41.1 (44.7)
2                43.7 (57.5)      52.6 (58)

Symmetrical gaps:
sphere diameter:    5              10
gap spacing:
0.5              14.3 (17.5)      15.0 (16.9)
1                26.6 (32.2)      28.6 (31.6)
1.5              37.4 (46.1)      41.3 (45.8)
2                47.0 (58.3)      53.2 (59.3)

The values in the tables are quite strange. Why would the voltage
decrease for the 10 cm spheres at small spacings? Some values look
too high.

Trying some values at the end of the table for symmetrical gaps:
Spheres with 200 cm:
Spacing:
70        1694 (1560)
80        1878 (1730)
90        2051 (1900)
100       2214 (2050)

Now my values are above the table. My values are at about 1%
from the theoretically exact (assuming Emax=30 kV/cm).
I found something curious: Anything behind the spheres increases
the breakdown voltage. May explain the high values for small
spheres in the table.

Antonio Carlos M. de Queiroz