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Re: Optimal toroid elevation
Hi Marco,
Using the dimensions you give here, I plugged the following into
E-Tesla5.21. You may want to check my numbers...
E-TESLA V5.21 May 26, 2000 Terry Fritz
20:25:28 05-26-2000
Grid Size = 120
Scale Multiplier = 1
Terminated Coil
Ceiling Distance = 200
Wall Distance = 100
Primary Height (Inner Turn) = 0
Primary Inner Diameter = 20
Primary Outer Diameter = 30
Primary Height (Outer Turn) = 0
Secondary Base Height = 7
Secondary Diameter = 15.75
Secondary Length = 59
Secondary Inductance = .0882
Terminal-1 Height (center) = 85
Terminal-1 Radius = 4
Terminal-1 Diameter (torroid only)= 51
Terminal-2 Height (center) = 85
Terminal-2 Radius = 0
Terminal-2 Diameter (torroid only)= 0
Top Voltage = 100
Pass Ccalc (pF) % Change Fcalc (Hz)
100 C= 10.45974 10359.74 F = 165701.1
...
1900 C= 79.79104 .1575558 F = 59994.13
The stress plot is at:
http://users.better-dot-org/tfritz/site/misc/marco01.gif
Note the very high stress at the top winding of the secondary. This looks
like it would definitely have a good chance of arcing.
The field plot is at:
http://users.better-dot-org/tfritz/site/misc/marco02.gif
This plot does not look to bad. but the stress plot above is the key here.
I then ran it with a 4 inch diameter corona ring at the top of the
secondary winding:
The stress and field plots are here:
http://users.better-dot-org/tfritz/site/misc/marco03.gif
http://users.better-dot-org/tfritz/site/misc/marco04.gif
The ring helps a little but is not really that good. I think the toroid is
simply too high. I ran it with the toroid center 11 inches above the top
winding (instead of 19 inches as in the first example) and I got the following:
http://users.better-dot-org/tfritz/site/misc/marco05.gif
http://users.better-dot-org/tfritz/site/misc/marco06.gif
Note the far reduced stress at the top of the secondary winding and the
much more natural oval shape to the top E-fields. "I" think this is the
way to go. Put the terminal center about a foot above the secondary top
winding would be my guess. I would have a thin ring (like 1/2 inch tubing)
as a corona ring to keep the top winding from burning if it does have an
arc. I don't think the ring will help much with field control however.
Cheers,
Terry
At 10:43 AM 5/24/00 +0300, you wrote:
>Hello all.
>
>Can anybody please give me some hints about how much should be the distance
>between the top of the secondary coil and the middle point of the toroid for
>the
>Thor coil?
>
>The Thor secondary is 70" tall, winding is 59" long (about 4" left between top
>turn and top of the secondary form).
>
>The toroid is 59" outer diameter, the aluminium duct used is 7.9" diameter.
>
>I thought to rise the toroid about 15" - 20 " over the secondary top: any
>comments about that?
>
>Should I use also an anti-corona smaller toroid near to the last top secondary
>turn?
>
>Regards
>
>
>