Secondary Frequency(fwd)

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: Secondary Frequency(fwd)
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 19 Aug 1998 23:45:02 -0500
Approved: tesla-at-stic-dot-net

----------
From:  chris.swinson [SMTP:chris.swinson-at-zetnet.co.uk]
Sent:  Wednesday, August 19, 1998 7:49 AM
To:  Tesla List
Subject:  Re: Secondary Frequency(fwd)



SNIP
>
>L is affected by the radius of the coil (geometry) as the radius is used to
>calculate the inductance where L=(R^2 x N^2) / 9R + 10H, here R=radius,
>N=number of turns, H=height. This is known as the Wheeler formula.


Sod this mate, Its wrong some how.  Many people have got the same calculated
results as me but to my actaul coil measured a lot less.  My coil was
suppoed to be about 39mH but actual measurmet showed about 8Mh.  I have done
many other coils, all are wong to the above calculation.  I don't calculated
anything anymore, I just measure it all now, and wha tI carn't measure I
guess at ;-)


All the beST,
Chris.

chris.swinson-at-zetnet.co.uk
www.users.globalnet.co.uk/~mega01/    <--- moved site to...
www.users.zetnet.co.uk/mega.disczine/





-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: 'Tesla List' <tesla-at-pupman-dot-com>
Date: 19 August 1998 06:10
Subject: Secondary Frequency(fwd)


>
>----------
>From:  Barton B. Anderson [SMTP:mopar-at-uswest-dot-net]
>Sent:  Wednesday, August 19, 1998 2:35 AM
>To:  Tesla List
>Subject:  Re: Secondary Frequency(fwd)
>
>Reinhard,
>I would say "He" (whoever He is) is right. Geometry is significant in the
>formula (1/ 2pi LC).
>
>L is affected by the radius of the coil (geometry) as the radius is used to
>calculate the inductance where L=(R^2 x N^2) / 9R + 10H, here R=radius,
>N=number of turns, H=height. This is known as the Wheeler formula.
>
>C is affected by the H/D relationship (geometry). This is the Medhurst
>formula where C=K x D.
>C = solenoid self-capacitance in picofarads.
>K = a constant which depends on the ratio of the coil height and diameter.
>D = diameter of solenoid in centimeters.
>
>For coil A, I calculated L = 23.9mH and C = 7.9pF and came up with 367kHz
>(unloaded).
>For coil B, I calculated L = 40.6mH and C = 7.4pF and came up with 290kHz
>(unloaded).
>
>Based on my assumtions, I came up with values different than "He" did, but
>our relationship is the same. If you think about how proximity affects both
>inductance and capacitance, you can get an idea of why geometric dimentions
>are necessary and why these two formula's are used.
>
>Hope this helps,
>Bart
>
>Tesla List wrote:
>
>> ----------
>> From:  RWB355-at-aol-dot-com [SMTP:RWB355-at-aol-dot-com]
>> Sent:  Tuesday, August 18, 1998 12:31 AM
>> To:  fwd
>> Subject:  Secondary Frequency(fwd)
>>
>> Hi to All,
>>
>> Below are two given coils.
>> What is the frequency of each coil? Another coiler and I disagree on the
>> resonant frequency of these two coils. Can somebody help?
>>
>> Coil A:
>> 21.7" long
>> 3" diameter
>> Wound with 1230 feet AWG 28
>> He says 418kHz (I say 200 kHz)
>>
>> Coil B
>> 10.84" long
>> 6" diameter
>> Also wound with 1230 feet AWG 28
>> He says 275kHz (I say 200 kHz)
>>
>> Who is right??
>>
>> Thanks,
>> Reinhard
>
>
>
>
>