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Em 19/03/2014 22:05, alfred erpel escreveu:
Hello All,
I am preparing to wind a flat spiral coil using stranded steel cable. The steel cable is galvanized and has a .030 thick vinyl coating. (this may be used for a choke or other purposes at 60hz, but NOT as a primary in a tesla coil). It is 7x19 cable measuring .125 diameter without the insulation. The 7 part of the "7x19" means there are 7 big wires, one in the middle with 6 wires twisted around it. The 19 part of the "7x19" means each of the 7 wires is comprised of 19 really small wires twisted together. The seven big (composite) wires are rotating clockwise down the wire. Each of the 7 wires has the 19 wires rotating counter-clockwise.
See this image for the cross section which I just explained above. http://www.steelwirerope.com/images/Constructions%20Images/General%20Purpose%20Ropes/MainImages/7x19Main.jpg
question 1: I want maximum induction from my flat spiral. Can it be determined from the information provided whether to wind clockwise or counterclockwise? Also, this If so, please explain.
question 2: [not related to example described above] If someone were winding a flat spiral primary with 10 gage stranded copper wire created with ALL the strands wound clockwise, would the resultant inductance be affected by whether way the flat spiral coil was wound clockwise or counterclockwise?
The way how the cable is wound is practically not important. All the
wires are in contact, and the whole cable acts as a single conductor, at
least at low frequencies. The geometry of the coil dictates the
inductance. As the cable material is magnetic, the inductance will be a
bit larger than the inductance of a similar coil built with a
nonmagnetic metal without magnetic core, but I would not expect great
difference. With steel, the series resistance may be 10 times larger
than in the same coil made with copper wire.
