Quote from: Magluvin on August 05, 2012, 11:45:42 PM
Hey Broli

In your pic above, is the magnet suppose to spin? If so, does it work with ceramic magnets, or does the magnet need a nickle coating, like neo mags?

Thanks

MaGs

In the pic, the grey vertical conducting rod should experience a force away from the magnet (according to the original Faraday experiment) and follow the two grey horizontal conducting rails.  Nothing is supposed to rotate in this example and the magnets can be ceramic or nickel coated.  However, this example has a high probability of failure, and if it does fail then it would be contrary to the statement of there being an outwards force in the original Faraday homopolar motor experiment. 

Gravock

Quote from: broli on August 05, 2012, 05:56:33 PM
It's interesting but the vector potential math is honestly a bit above my head. However he makes an interesting point on the original Faraday homopolar motor experiment where the wire piece being apparently parallel to the field lines, undergoes both a torquing force and an outward one. However according to that statement the same wire piece on a rail should be pushed away from the magnet which seems like a too basic experiment to have been overlooked .

Broli,

I found a video showing the original Faraday motor experiment using salt water instead of mercury.  There does appear to be both a torquing force and also an outward force on the wire piece.  Does the outward force on the wire piece disappear if the wire piece isn't translating or moving around the magnet?

This reminds me of a publication by Muller, titled "Experimental Test of the Normal and Retrograde Railgun Accelerators", where the aluminum rod advanced in the forward direction as expected (away from the battery bridge) whereas the steel (magnetizable) rod advanced backwardly when they're allowed to roll.  When the same system is setup vertically, however, and the transversal rod is suspended on a balance (without rolling), no retrograde behavior is observed for the steel rod. Both, aluminum and steel rods, moved in the forward (expected) direction. The conclusion is that rolling of the steel rod is essential to observe its retrograde motion.

Is this the conclusion on the original Faraday experiment, "the circular motion of the wire piece around the magnet is essential to observe it's outward force"?

Edited:  Here's another video of the original Faraday motor experiment.

Gravock

Here's a really good video showing an outwards force on the wire piece as it moves around the magnet.

Gravock

Broli,

If we slightly modified the original motor experiment by gluing a portion of the wire piece to the rim of the magnet to prevent an outward force from acting on the wire piece, would we still have rotation?

If we don't have rotation, then does this mean the outward force acting on the wire piece is essential to observe a rotation?  Can't have one without the other, or can we?

Gravock

Broli,

Do you think the rotating wire piece being pushed away from the magnet is nothing more than the centrifugal force?  The centrifugal force definitely needs to be ruled out, so I'll be devising an experiment to check for this.  I have two axially magnetized magnets 2" dia. and 3/8 in. thick.

Gravock