[Prev][Next][Index][Thread]
Re: Primary Flashover
Max,
Tesla List wrote:
> Original Poster: RODERICK MAXWELL <tank-at-magnolia-dot-net>
>
> Last night I decided to really give my six inch coil a real workout. I
> set the system up and cranked the variac up to 100% with one of my
> smaller toruses attached. Everything worked out fine, got 36" discharges
> easily. Then I decided to change the toroid to a much larger one to see
> if I could make it breakout. As soon as the gap fired there was a bright
> light at the base of the secondary, and no sparks from the torus. At
> first I was not sure were the light was comming from and thought the cap
> was blown! After breaking out in a cold sweat I began to search around
> for the problem. The first turn of the primary had flashed over to the
> base of the secondary leaveing a nice burn on the side of the coil form!
> Luckily the damage was only cosmetic. If I had been running at 5Kva it
> would have blown a hole in the secondary.
If the damage made a burn, then there is more than just a cosmetic effect.
The burn area is probably black and carbonized. You should clean it and make
sure there is no secondary turn to turn short, then recoat the area. If
there is a turn to turn short, you can remove the shorted turns, reconnect
the winding, and recoat.
> I don't want to change the
> coupling by removing the first turn of the primary or raising the
> secondary. Does anyone have a solution?
As soon as you put the toroid on, you changed the LC of the secondary. You
may want to tune up at lower power and try again. If you still have the
problem, you might try wrapping the lower portion of the secondary with
kapton tape, electrical tape, etc... This might add volt/mil between the
primary and secondary. Otherwise, you will probably have to make a coupling
adjustment.
Bart