Re: Inductance of a conical coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 >
 > Original poster: "John H. Couture by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
 >
 > Antonio -
 >
 > I checked the Inca program for a primary flat spiral, 30 degree conical and
 > solenoid coil. The primary was from the JHCTES default example.
 >
 >           Flat Spiral    Conical     Solenoid
 >
 > Pri Ind    44.14 uh     45.35 uh     43.48 uh
 >
 > The conical coil inductance should be between the flat spiral and the
 > solenoid? All three primaries have the same average radius.

You tried the version that was using the "uncorrected" formula for
conicals.
Please obtain the corrected version in:
http://www.coe.ufrj.br/~acmq/programs
The program now accepts fractional turns too.
Teslasim was also updated.
With a coil with average radius = 0.3 m and winding width = 0.2 m I
obtain,
for 100 turns:

angle       Inca     Fantc
0 (flat)   7.70 mH   7.56 mH
45         7.51 mH   7.58 mH
90         7.56 mH   7.6 mH

Really, the correction factor is not working well for this geometry, but
the main problem is the formula for the flat coil.

 > As I mentioned in my other post I believe all three of these inductances
 > would be the same value when tested provided they had the same avg radius.

Not exactly, but very close.

Antonio Carlos M. de Queiroz