Re: Shorted turn?

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Pyrotrons-at-aol-dot-com>

Hello Steve and All.

> Doesn't the toroid on top of the tesla coil act like a shorted turn? 

> I'm not sure how you'd prevent without causing sharp edges. Perhaps 
> all that would be required is a small gap that would be sort of self
>shielded by simply being a very small gap. I don't think I'm describing 
> what I'm visualizing very well.

Yes, the toroid does act as a shorted turn, but as you mentioned it is  *most 
likely* inconsequential. In theory it reduces performance because the turn 
acts another secondary coil............a one-turn secondary coil.......and 
will have a strong current induced into it, which is then turned into heat by 
the wire's resistance. Heat = loss. 

As far as I know, noone has "tackled" trying a toroid with a split in it. I'm 
sure it's a lot more hassle than it is worth. Shorted turns on a secondary 
coil are definately not good for performance, we know this already ; )

Usually, shorted turns on the secondary are found down at the bottom end 
where the coupling is greatest from the primary coil. Shorted turns on the 
lower end will drastically reduce performance, whereas shorted turns up by 
the toroid carries a lesser significance.

A good test would be to take a clipcord and wrap it around the secondary coil 
and clip the ends together. Try this at the bottom of the coil and it will 
get hot from the induced high currents.....

Try laying it ON the primary and it will melt apart at a kiloVA or so.....

So I threw in some extra...... ; )

Justin Hays
KC5PNP
G-3 #1150
Email: pyrotrons-at-aol-dot-com
Website: www.hvguy-dot-com