Re: tesla coil uses an air core. why?

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

HI Larry,

On 10 Aug 2002, at 6:49, Tesla list wrote:

> Original poster: "Laurence Davis by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <meknar-at-hotmail-dot-com>
> 
> why does it use an air core?
> 
> i thought of several reasons.
>   1)  core material choices don't operate well at the range of
>       frequencies that tesla coils operate. (hysteresis loss?)
>   2)  eddy current losses?
> 
> but what would happen should you decide to use a core?
> 
> 1) perhaps nothing at all.  the hysteresis loss would further dampen
>    the pulse from the primary.
> 2) the eddy current losses would further reduce the output efficency.
> 
> 3) how about delaying the flux from the primary with a diamagnetic
>    materaial?  perhaps wood?
> 
> have i missed any negatives that would prove air is the best core?
> 
> larry.

One point I'd make is that you can store an unlimited amount of 
energy in "air" without suffering serious non-linearities.

Regards,
malcolm