On Sat, 27 Jun 2009, John Berry wrote: > After re-reading I still fail to understand your contact point thought, but > is it merely to produce a magnetic field in the shaft?
A Faraday motor has a radial current in a disk, and a magnet to produce a b-field perpendicular to the disk. This produces a torque between the disk and the sliding contact at the edge (but zero net torque on the permanent magnet.) If instead we remove the magnet and place a coil on the copper disk, and route some current through the coil, the motor still spins. If instead of a coil, we carve spiral slots into the copper disk, which forces the current to have a circular component as well as radial, the motor still spins. DOH! I wrongly called these "self-acting" Faraday motors, but the real term is "self-excited," as with standard DC generators where the generator output is used to "excite" the generator's own field coil. If we short out a self-excited Faraday motor, then spin the shaft, it starts generating a current. But this only works above a certain RPM, where the output energy is greater than the resistive losses. > If we used a magnetized shaft, north at one end south at the other would > this still be required to create the effect? That would work. A magnetized shaft would turn it into a conventional Faraday motor. I'm looking for an effect which would drive an all-copper ball bearing motor into rotation. > Is the force you are envisioning one that puts a torque on the individual > ball bearings? Yes, a relative torque between each bearing and the ring enclosing them. (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 206-762-3818 unusual phenomena, tesla coils, weird sci
