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- To: tesla-at-pupman-dot-com
- Subject: Re: Magnet Design for Tesla Coils
- From: TimRaney-at-aol-dot-com
- Date: Wed, 12 Mar 1997 19:59:36 -0500 (EST)
In a message dated 97-03-12 00:38:21 EST, you write: Bert (and all): No, I didn't see a significant difference in performance as compared to series gap, for example, but based on what follows, I think magnetic quenching is a viable method to investigate. I have not tried a "high velocity vacuum gap" as you mentioned. One problem I introduced (yea, I screwed up due to my ignorance) was the electode geometry in the magnetic field. I built an enclosed spark gap so I could evacuate it with a vacuum pump; the electrode geometry closely resembled the World War II vintage RADAR spark gap tubes, i.e, an cylindrical aluminum cathode that was concentric to a tungsten anode (the design minimizes electrode erosion). The spark gap worked great (at atmospheric pressure) without a magnetic field, its performance was equal to a series gap. With a magnetic field applied, there was no discernible diference in performance. However, I placed the tube in a magnetic field so the tubes' axis was perpendicular to the magnetic field. Gee, sounds good! But, with the electrode geometry I described, the spark propagates perpendicular to the tube axis. In other words, the spark path was parallel to the magnetic field and does not aid in quenching the spark. Live and learn! So, can't comment on higher fields based on my erroneous set-up, but I think it's worth looking into. In using an enclosed spark gap, the glass envelope acted as an insulator when the spark gap was placed within the magnets' gap; with an open air gap, I used mica sheets with some success, but they don't always hold up when using a 15KV, 60mA sign transformer. The other idea is to perhaps adapt the ceramic nozzle assemblies used in MIG welding equipment (check out a local welding supply store for things other than tungsten TIG rods) as insulators. Hope this helps, Bert and that my mistakes might benefit others. But hey, how else do we learn? Too bad there wasn't an easier way! TIMOTHY RANEY, TCBOR
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