Hey Dex,Yeah, you're probably right. Reduced coupling was the consensus on the list when I brought this topic up about four years ago. At the time I was trying to get maximum output from a pig powered coil where I went through three iterations of increasing primary diameters, starting at two feet and ending up at three feet. In each case I increased the coupling until racing occurred and then backed off a tad and measured the arc length. At two feet I was getting 10-foot arcs, at 2.5 feet, 12-foot arcs and at three feet, 14 foot arcs at which point I quit since I had hit the end of my budget and the theoretical limit for the power and size of the coil. One of my motivations for trying large diameter primaries was a comment made by Richard Hull in which he stated that for best output the primary diameter should be approximately equal to the height of the secondary winding.
Since then, however, I've noticed many successful coils with fairly compact primaries, most notably those built by Greg Leyh, and in particular, Electrum in which the primary was actually inside the secondary. Now I have to assume that Greg would have investigated all manner of primary configurations before settling on the final design, and so I'm probably wasting my time. But I still want to male some comparisons on this new DRSSTC, if for no other reason than it gives me something to do.
Dave Pleasanton, CA At 04:29 AM 2/19/2010, you wrote:
Most likely,higher coupling results in more secondary energy (and voltage stress). Efficiency of the energy transfer is higher, but what's more important,secondary streamers has less time to dissipate supplied energy. By increasing primary diameter you reduce coupling and secondary structure is less stressed. Your DRSSTC seems to be quite a big. Can you give max input power and BPS you are running? Secondary geometry parameters,and coupling between coils would also be nice to know for comparison purposes. Dex --- dave@xxxxxxxxxx wrote: From: Dave Leddon <dave@xxxxxxxxxx> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> I found that when I started using your boost converter I began to experience racing sparks which I attribute to higher supply current. It has been my experience that increasing the primary diameter allows for greater output before racing sparking occurs. I plan to make some measurements with both primaries and report more on this topic later. Dave Leddon Pleasanton, CA _____________________________________________________________Washington DC's Largest FREE Email service. ---> http://www.DCemail.com ---> A Washington Online Community Member --->http://www.DCpages.com _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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