- Joined Jan 17, 2007
I didn't understand it either, until I visualized that not only the magnet's poles are alternated but the coil's directions too. For instance, the wire in coil #1 is wound in a counterclockwise direction, while the wire in coil #2 is wound clockwise.I'm not so sure that the illustration is correctly showing how the magnetic force would be in the way it's expected. With the magnets arranged like this . If they were arranged with all of the poles the same yes, but with them alternating I don't think so. But could be wrong, and would like proof. I'm basing my thinking on how a magnetic work holding chuck is made, how the lines of force are in them.
Let's assume that the magnets are rotating clockwise. When magnet A crosses the pair of coils #1 and# 2, it induces a current flowing away from the center of rotation, while magnet B induces a current that flows towards the center of rotation (because it has the opposite polarity of magnet A) as it crosses coils #2 and# 3. This creates a current flowing counterclockwise in coil #1, and clockwise in coil #2. And the sum of both flows in the same direction inside the wire, because of the way that coils are connected. If the coils directions and the magnet's polarities were not alternated the current in each coil would "crash" against each other, and it wouldn't flow out of the device. The only result would be that heat would be generated.
All you have to do now is visualize this same situation in the rest of the coils. And as you can see, only alternating current can be produced this way.