Re: Number of turns for a secondary?

• To: tesla-at-pupman-dot-com
• Subject: Re: Number of turns for a secondary?
• From: mark <moyson-at-tig-dot-com.au> (by way of Terry Fritz <twf-at-verinet-dot-com>)
• Date: Mon, 04 Jan 1999 17:03:26 -0700
• Approved: twf-at-verinet-dot-com

Hi,

What is the wheeler equation??

mark


>Original Poster: Hollmike-at-aol-dot-com 
>
>In a message dated 1/3/99 3:00:04 AM Mountain Standard Time, tesla-at-pupman-dot-com
>writes:
>
>> 
>>  This thread has made me curious as I plan on winding a larger diameter
coil
>>  soon myself. I always thought that you decreased the gauge of the wire (
>> fewer
>>  turns per inch) to keep the H/D ratio compatible with the number of turns
>>  (ideally somewhere between 4:1 or 5:1 & under 1000 turns). I thought that 
>> was
>>  why (aside from the current being carried) the larger coils always used a
>>  heavier gauge wire. Like I said I'm just curious & I know a lot of other
>>  factors come into play in the design. Thanks,  Jim
>>  
>Jim,
>    According to one reference I have  the maximum inductance of a single
>layer solenoid coil occurs when the H/D ratio is 2.46:1.   I once did a long
>drawn out calculation(based on the Wheeler equation) that showed this to
occur
>at a ratio of 2.22:1.   My calculation was based on a fixed length of
wire, so
>the number of turns went down as the diameter goes up.  It seems to be in
fair
>agreement with the text.
>    This doesn't mean that that is the best design for Tesla coils though.
>One still has to consider the coil's self capacitance and it's ability to
>withstand the high voltage difference between each end(probably the most
>important aspect in the design criteria).  This is probably why most coilers
>design them with H/D ratios from 4:1 - 6:1.   
>Hope this helps,
>Mike
>
>
>

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