---------- Forwarded message ---------- Date: Wed, 20 Dec 2006 20:46:44 -0600 From: Shaun Epp <scepp@xxxxxxx> To: Tesla list <tesla@xxxxxxxxxx> Subject: Re: (Re) Wire Length (fwd)The common equation used to calculate inductance for a spiral is shown below and was copied from
http://tesla770.tripod.com/id5.html Spiral Coil Inductance L = inductance of coil in microhenrys (µH) N = number of turnsR = radius of coil in inches (Measure from the center of the coil to the middle of the wire.)
H = height of coil in inches Shaun Epp----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx> Sent: Tuesday, December 19, 2006 2:18 PM Subject: (Re) Wire Length (fwd)
Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx> ---------- Forwarded message ---------- Date: Tue, 19 Dec 2006 05:05:06 -0500 From: Jared Dwarshuis <jdwarshuis@xxxxxxxxx> To: Pupman <tesla@xxxxxxxxxx> Subject: (Re) Wire Length Hi: BartI have not wound any flat secondary (yet). I am wondering if the inductancecan be roughly calculated as: L = [4 pi x 10^ -7 x (wire length)sqrd] / [ 4 pi Radius ]They say that Tesla used wood boiled in linseed oil, I have not tried this. If i were to do this (for reproduction purposes) my choice of wood would bespruce or similar softwood. I say this because many hardwoods (especialy wood from tropical enviroments) have minerals in the grain thatare likely to be somewhat conductive. ( teak is horrible, you can see sparkswhen the carbide blade hits the mineral pockets) Yes racing sparks are fun to look at; but all that effort up in smoke! With some coils there is a race to get the coil tuned before it destroys itself ( part of the price you pay for leaving the beaten path I suppose.....)Seems like a flat coil would make a rather neat half wave. You could have askinny toroid capacitor around the outside. And a sphere or toroid in the center. With proper ballance you might get the crazy motion of a quarter wave coil, but restricted between points. ( and best of all; no ground to mess with!!) Sincerely: Jared Dwarshuis
Attachment:
spcoilind.gif
Description: GIF image
Attachment:
pic.gif
Description: GIF image