[Prev][Next][Index][Thread]
Secondary Frequency(fwd)
-
To: "'Tesla List'" <tesla@pupman.com>
-
Subject: Secondary Frequency(fwd)
-
From: Tesla List <tesla@stic.net>
-
Date: Wed, 19 Aug 1998 23:45:02 -0500
-
Approved: tesla@stic.net
----------
From: chris.swinson [SMTP:chris.swinson@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@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@pupman.com>
To: 'Tesla List' <tesla@pupman.com>
Date: 19 August 1998 06:10
Subject: Secondary Frequency(fwd)
>
>----------
>From: Barton B. Anderson [SMTP:mopar@uswest.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@aol.com [SMTP:RWB355@aol.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
>
>
>
>
>