Thanks DC.Even limited specs help me out. 30" sphere requires a pretty high voltage to breakout. A 12" coil or larger is not surprising. I'll do some calc's and see what I can come up with.
Take care, Bart resonance@xxxxxxxxxxxx wrote:
This was a long time ago, but sec was 12 inch dia. and pri cap was .04 uF with a 30" dia sphere topload. They can use JAVATC to do the complete design. Regards, DCHi DC, Well then, got any specs on the coil it ran on? If so, please send (off list is fine). I agree on the field control if comparing to a single sphere. However, Terry's Piranha coil and David's specs are pretty good examples of how to attain nice field control with sphere's. Looking at David's data, his coil is heavily top loaded. That's pretty cool! I think sphere's in this type of configuration may offer slightly more topC than a toroid of same minor and major dimensions. I guess it's the full sphere surface area versus the toroid surface area. Kind of caught me off guard. I had to get to a 9"x32" toroid to match his assumed frequency with the sphere's (assuming the cap really was .028uF). I imagine the price between the two is similar (not sure). If the 4 sphere configuration is lower cost, it might make for a low cost polished top load with good field control like a toroid. Take care, Bart resonance@xxxxxxxxxxxx wrote:Years ago, I used a 30 inch dia. alum. sphere on one of my coils. Seems to work fine but a toroid does offer better electrostatic field control. Dr. ResonanceThanks Gary. Maybe Mr. Weaver is the man! Thanks Bart Lau, Gary wrote:Nope, it wasn't me. But Gary Weaver comes to mind. Regards, Gary Lau MA, USA-----Original Message----- From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of bartb Sent: Monday, February 18, 2008 6:18 PM To: Tesla Coil Mailing List Subject: [TCML] Sphere Topload Coil Hi Everyone, Sometime back (quite a while I guess), I remember photo's of a pretty good sized coil with a large sphere top terminal (I'm thinking about 20" diameter). For some reason, Gary Lau comes to mind but I'm not sure. I'm curious of big sphere's and the system that drove them. I'm looking at breakout voltage as based on surface field strength and it would be nice to know a little something on the basic specs of those coils. So if anyone meeting those specs isn't too busy with life, please post some specs. I don't need the whole gap scene or anything of that nature. Just the basic secondary, top load, cap, and power supply data. Also, was a breakout point required or not would be nice to know. Reason: I'm advising someone regarding a rather large coil with a very large sphere. From my calculations, the sphere I think is too big for breakout on it's own. Calc's are one thing and those of you well experienced with sphere's may help fill the gap of uncertainty. Thanks, Bart
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