View Single Post
 
Old 09-02-2013, 09:14 AM
Sebacid Sebacid is offline
Junior Member
 
Join Date: Jul 2012
Posts: 18
Quote:
Originally Posted by wayne.ct View Post
Correcting my error and still using 750 KHz as my center frequency, this is what I get...

Calculation #1

L = Total length of coiled wire

L = c/w = 299,792,458 (meter / second) / 2 * PI * 750,000 (/second)

= 299,792,458 / 2 * 3.14159 * 750,000 (meters) = 63.62 meters = 63.62 meters / .3048 (meter / ft)

= 208.7 feet

Calculation #2

L = Length of each turn = 208.7 feet / 20 = 10.44 feet = 10 feet 5.23 inches

Calculation #3

Circumference C = L; Diameter = Circumference / PI = 3.32 feet = 3 feet 3.86 inches

H = Coil height = 0.2 * Diameter = 0.2 * (10.44 feet / PI)

= 7.97 inches

Calculation #4

Max diameter of wire. Space between strands of wire is 62 percent of wire diameter.

20 turns take 7.97 inches ===> 1 turn takes 7.97 inches / 20 = 0.4 inches

0.4 inches = 162 percent of wire diameter ===> 100 percent of wire diameter = 0.4 / 1.62

Wire diameter = 0.246 inches (max.)

AWG 3 has a diameter of 0.2294 inches / 5.83 mm.

AWG 3 has resistance of 0.646 ohms / Km. which is 0.197 mOhms / ft.

For 208.7 ft, the coil will have 395 mOhms or 0.4111 Ohms resistance.

Now we have a manly sized inductor! 'Sorry to say I will not be building that any time soon! Thanks for the ride!

At the same time, my intuition was telling me this was going to be a large coil. So, I feel a bit better knowing my gut was in the ballpark.
You can always use another frequency (higher), then the coil, wire etc. size will be smaller. Try for something in between 2000-3000Kc/sec? As Dr. Green said earlier, the idea is to magnify the chosen frequency to the max!

Don't give up, build a smaller one first, experiment on it and if succesfull, upscale it on the next one!

Cheers,

-Seb
__________________
 
Reply With Quote