-- BEGIN included message
- To: tesla-at-pupman-dot-com
- Subject: Re: Why does top capacitance work?
- From: FutureT-at-aol-dot-com
- Date: Thu, 13 Mar 1997 09:50:25 -0500 (EST)
<< Hi John, You wrote in reply.... > > Different K's have to be used for the comparisons because the > > magnifier will not work properly using the low K's of the classical > > coil. The gap losses will be different and that will determine > > which is the better system. The overall efficiency and not the >> operational mode would be the main interest. > I think it is obvious which is going to win under those conditions > isn't it? > > I would like to see someone try all of the test combinations you >> mentioned for critically coupled coils. If no one has ever built a > > critically coupled Tesla coil it's about time this possibility be >> researched in all its variations. > I have scoped operation of running coils and under >90% of all > streamer conditions they were over-coupled. The beat envelope was > clearly present. A critically coupled circuit by definition loses as > much power in the primary resistance (gap) as it does in the > secondary (discharge). That can't be an ideal to aim for can it? > In fact, the only time I was able to reduce the beat envelope to a > single transfer was with a discharge rod positioned at a rather > critical distance away from the secondary. > I once tried bringing a 2-coil system to critical coupling under > non-spark conditions in the secondary. I had to lift the secondary 3 > feet+ clear of the primary to achieve this. It simply could not > produce a discharge under those conditions because the energy > transfer losses were so great. > > For example, has anyone set up a Tesla coil with a single hump physical > > coupling arrangement and determine if this gives Rp = Rs? How did the > > controlled spark length compare with the different combinations? > Terman and others state that critical coupling is achieved when the > reflected resistance the primary sees is equal to its own resistance. > Rs is never equal to Rp in a TC because of the transformation ratio. >In my experience it requires a 1:1 ratio for Rs = Rp under the > conditions you describe (e.g. an I.F. transformer in a radio set). > Worth noting too that Rp is non-linear in a good coil (gap losses > dominate all others). > > I believe there are many classical coil combinations (and magnifiers) that > > we have not explored that may offer advantages over what we are now using. > > > > John C. > I'd agree wholeheartedly with that. I am working on some right now. > Malcolm >> John, Malcolm, All, Yes, in general it seems that the looser the coupling the less spark is produced, I don't see how very loose (critical) coupling could be "better". John Freau
-- END included message