Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx> Hi Rich,I like to keep the topload as high as practical. Experimentation is how you find out. When the topload is too high, the top of the secondary windings may begin corona and even breakout. On my 8.5" coil, I actually keep the toroid only a couple inches above the coil, but this is not ideal. The coil sets on a 30" high base and then the coil is nearly 40", so the toroid ends up rather high in the garage. Because of this, it's better for me to keep the toroid low (practical). On my 4.5" coil which sets lower to the ground, I elevate the toroid about 4" above the coil because I now have the room to do so.
If you've got the room, then I would recommend a distance equal to the form diameter. If you don't, just lower it a couple inches above.
Take care, Bart Tesla list wrote:
Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>I have a question on the normal location of a top load. My new coil will max out at 13Kv .150ma , secondary is 6.5/8 dia , is there a standard starting point for the top load? I see pictures of other coils, some show it several inches above the top of the secondary winding , others are quite low with the lower part of the top load below the plane of the upper winding of the secondary.Any suggestions on a starting point ? Rich , from the middle of Missouri