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Low-frequency effective radius of a single-layer solenoid.
By David W Knight
 Main
article: Solen_r0.pdf
(version 2.06)+ Open Document spreadsheets: r0_rect.ods , r0_round.ods* , r0_numint.ods* , r0_round_p.ods* . *computationally intensive - may be slow to open. Abstract Due to path-length variation and strain, the current distribution in the wire of a solenoid inductor is not uniform at low frequencies. This causes the effective solenoid radius to differ from the physical average, leading to a systematic error in inductance calculations. Formulae and program routines for the effective radius, for coils wound with solid rectangular and round wire, are given. Principal references:  "Practical
Model and Calculation of AC resistance of Long Solenoids".
E. Fraga, C Prados, and D.-X Chen. IEEE Transactions on Magnetics,
Vol 34, No. 1. Jan 1998.
Formula for
the inductance of a helix made with wire of any section.
C. Snow. BS Sci. 537, 1926 (5.74MB PDF). |
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