Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx> Hi Ed,Good to hear from you. Thanks for sharing. My RSG is the same and knowing the RPM you've run, it certainly aids my comfort of my own. And your right, a guard is essential regardless of construction.
Take care, Bart Tesla list wrote:
Original poster: Edward Wingate <ewing7@xxxxxxxxxxxxxxxx> Bart,I've been following this thread for a while now and have a few comments in the interest of safety.First, I have put some pretty severe stresses on my rotary gaps and have never had an electrode come loose or fail (save one prototyping overload which melted the G-10). The series rotary on my magnifier has been run at 7500 to 8500 RPM at 13 KW for 5 to 6 minutes at a time. I have built dozens of rotary spark gaps for myself and others. I use a light press fit for the electrodes in the G-10 disk and set screws in the outer edge to hold the electrodes in place and have never had a set screw hole strip out or delaminate the G-10 as was mentioned in one post. The set screws are a must, IMHO and of course they need to be checked for tightness occasionally.Machining grooves in the tungsten electrodes for C-clips is not a good idea. The grooves would be a very good place for stress cracks to start, especially given the repeated heating and cooling and brittle nature of the tungsten and may result in a future failure. It's best not to break the ground surface finish of the tungsten in any way to maintain the integrity of the electrode.As always, the builder can use any methods that he or she sees fit, I'm just relating my experiences. A substantial guard is a must no matter what construction methods are used.Ed Wingate RATCBOriginal poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>Good idea Jared. Certainly, this could be done. But again, the clip is then exposed to outward forces. That might just throw another log on the fire. Seems the press fit is really the way to go, hands down.Take care, BartI wonder if you couldnt get a machinist to either put two small groves in a tungsten electrode (or in a sheath heat shrunk around the electrode) and then secure the electrode to the disk with circle clips on both sides. This would allow a pin that floated a few thousandths of an inch side to side until the electrode heated and expanded into a tight fit. (seems like this would place less compressive stress on the disk) Sincerely: Jared Dwarshuis