Re: [TCML] Design questions

[otmaskin5@xxxxxxx]

Thank you Bart, that clears it up.? Even bigger thanks for making JAVATC avaiable to us.? It is an incredible tool.? Dennis Hopkinton MA


-----Original Message-----
From: bartb <bartb@xxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Tue, 27 Jan 2009 9:15 pm
Subject: Re: [TCML] Design questions


otmaskin5@xxxxxxx wrote:?
> 1.? This is a table top coil so it will be operating on a table, stool or something off the ground.??When measuring heights (topload, top turn secondary, lowest turn, etc) for entry into JAVATC, do you measure height from the floor or from the table the coil sits on?? Heights are always based from the ground or floor to center of the conductor or top load.?
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> 2.? When JAVATC suggests a minimum distance between primary & secondary coils, how do you position the secondary within the flat spiral primary?? If minimum distance is supposed to be 1" between coils, is the secondary located 1" from the START of the primary?? If so, then at 1/2 turn of the primary, the distance would be slightly more than 1" as the primary spirals further from the center.? Or do you try to position the secondary equidistant between the start of the primary and the primary at 1/2 turn?? Or am I getting way too deep into this & it doesn't really matter??
Way too deep! Just kidding. Actually, I'm glad your looking at this aspect of coil design. When Javatc makes a recommendation of distance between the two coils, this is a distance based on the ability of the primary to arc to the secondary as based on the voltage at the turn as well as the radius's and their distance. It is not a coupling distance, but a "minimum" distance that should be maintained with the two coils. It is important to ensure you have your transformer section "real" and not just some arbitrary transformer as the voltage on the primary is based on the transformer inputs.?
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If Javatc states 1" minimum distance between primary and secondary, that indicates the arc voltage between the two coils is capable of a power arc between the two coils at a distance of anything less than 1". The distance is based on the "nearest" pointss of the coils. Note, that the start of the primary is always the "nearest" point, so this is it's base reference. However, also note that if you move the primary down or even away, that the distance between primary and secondary changes appropriately. This distance is the nearest edge of the secondary to the nearest edge of the primary regardless of how wide or how low the primary is. If you put a tape measure in a straight line between the two nearest edges of the coils, this is the distance you'll measure.?
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So use the start of the primary coil as your reference point in a straight line to the secondary nearest point. You can actually see this imaginary line by eye, but Javatc is calculating that distance as well as solving for the possibility of breakdown between the two coils based on the voltage at the inner turn. This was one of the more difficult scripts to write.?
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The reason I wrote this is that we often told our stories (estimates of what is too close or too wide). I simply let Javatc do the math. Low and behold, it was nearly identical to recommendations, except now with some theory math behind it. However, it is a "minimum" recommendation. I usually try to build 1/4" larger distance to assure I stay out of harms way (1/4" adds some peace of mind without causing a significant drop in k).?
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Hope this info helps,?
Take care,?
Bart?
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> Any help would be appreciated.? Thanks.? It's good to be back!?
>?
> Dennis Hopkinton MA?
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