[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 3rd harmonic trap

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I am not sure "why" filtering the 3rd harmonic is needed. But one could put a high-Q LC filter in parallel and short that frequency out on the primary. But you would still get the 3rd on the top voltage and secondary system so I am not sure "why"....

Filtering the secondary would be hard since it is not obvious how one would do it. The primary is already a real good high-Q filter, so the 3rd harmonic is very low. Simply the natural switching is responsible for a lot of that and you are not going to stop that much unless you run CW.

Filters like the protectors in the note could be modified. Just an LC circuit.... They can be made very high Q!! and high current!! Adding such a parrallel LC might do odd things like get other resonant frequencies going....

In the case of the protectors, they are in series and far off values so they just blend with the secondary (even though there are three inductors and three caps, it is still second order). They normally have very little effect.

Cheers,

        Terry

At 01:51 PM 3/23/2005, you wrote: 
On 23 Mar 2005, at 8:38, Tesla list wrote:

> Original poster: "Jolyon Cox" <jolyon@xxxxxxxxxxxxxxxxxxxxxxxx>
>
> if a 3rd harmonic band-reject filter or "trap" would not work, how
> about a band-pass filter tuned to the fundamental of the TC? Would
> this not a correct description of the of  circuit described in the
> following? http://drsstc.com/~terrell/notes/DRSSTCprotec.pdf

Has the scheme actually been tried? What is the effect on tuning of
the extra inductors capacitors? I thought a Tesla Coil was a bandpass
filter of sorts.

Malcolm