Re: [TCML] Sphere Topload Coil

[resonance@xxxxxxxxxxxx]

Yes, we had to use a "breakout" point off the top of the sphere to get
sparks.

DC


> 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,
>>
>> DC
>>
>>
>>
>>
>>> Hi 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. Resonance
>>>>
>>>>
>>>>
>>>>
>>>>> Thanks 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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Dr. Resonance

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