The homotenna (homopolar motor + antenna).

[Mark_Eric]

I'm confused by the comment that the external circuit/wire brushes provide the torque for a homopolar motor. I have taken a piece of copper wire, wrapped it around a AA battery with a neo magnet stuck to the bottom. The wire is wrapped in a big loop, top to bottom, "shorting" the + and -. The wire loop is then hung from a piece of thread, allowing the entire object to spin. The thread is tied to a pivot so that the thread doesn't wind up and halt the spinning. Which it happily does till the battery runs out. If I use a big enough loop and thick enough wire, that can be 15-20 minutes. So, other than the string resisting gravity, the object is spinning without anything external.

Is this odd? I've been planning on making one with three tiny solar panels instead of the battery. Presumably then it will just keep spinning as long as light is shinning on it.

[broli]

Please make take a picture or make a video of your setup. It's hard to visualize what people are talking about sometimes, it's the curse of knowledge . As to the wire causing and having a torque acting upon it even the most basic homopolar motor setup shows this:

http://www.youtube.com/watch?v=FU13Ftqfkh8&feature=player_detailpage#t=34s

It's just Newtons's third law.

And like I said a few times now, explanations like these are wrong:

http://www.youtube.com/watch?v=kDxc3QLke1k

It's not the rotating circuit glued to the magnet causing the torque, this is a blatant violation of Newton's third law, and completely ignores the stationary outside circuit which is screaming "hey dude don't you see the force is being acted on me so I'm acting on something else".

[gravityblock]

The latest thread on homopolar motors made me think about some old concepts again, one of them being the "homotenna" idea.

I had this new idea and thought it was worth sharing at the very least.

The concept is simple, you have a coil wrapped around a ferrite core. This would be your rotor. Then both ends of this coil are connected to rings sliding against brushes leading to your exterior circuit. One lead of this circuit is electromagnetically shielded.
The circuit is then energized with HF AC, the high frequency being crucial and somewhere between 10kHz-1Mhz so the shield can do its job shielding the electromagnetic field.

The theory behind it is also simple. We already know that the external circuit in a homopolar motor causes the torque on the disk/magnet assembly. However if the below concept were to be energized with DC current both external wires would cause an equal but opposite torque on the rotor assembly leading to no motion. But if we were to replace the PM with an EM and fed it with HF AC current through the stationary leads AND we can shield one lead completely so its EM field becomes invisble to the rotor then a net torque could arise. Since both the current in the coil and the current going through the external circuit lead are the same and synchronized, this should lead to a torque acting only in one direction on the rotor. And since there's no coil part going from rim to center, there should be no induced back emf.

The key here is the shielding of the field of one lead and making it disappear to the rotating magnet. This is much more efficient than the antenna idea as currents can be higher and frequency lower.

I've also been thinking of the homotenna idea.  It's good to see this topic being revived once again.  The text below are excerpts which I believe supports the concept of this thread taken from a publication titled, "The Faraday Motor Principle As A Method For Free Energy And Craft Levitation And Propulsion".

In figure 1 there is shown a pressure wave associated with the magnetic potential A vector and the magnetic flux B field. The A vector and the B vector are normal (90 degrees) to each other and both are also normal to the outwards moving pressure wave.  It has been demonstrated that a strong enough magnetic field can suspend a live frog with the associated pressure wave of that same field without harming the frog. The pressure wave works on the individual particles on the quantum scale in a collective manner much as gravity does.  The pressure wave will increase as the square of the current. For a 100 ampere current, the value will be 10,000 times larger than a 1 ampere current. The adjacent current element may be used to cause a directional projection of the force field resulting from the pressure wave and the fixed current element. This current element can also move if free to do so.  The external current element can be used to introduce asymmetry into the uniform pressure field and therefore cause a force unbalance that can do work on the system so as to move it in the desired direction.

The outward moving pressure wave is divorced from the magnetic field proper and therefore can be used to move the entire system via Newton's law of every action engenders an opposite and equal reaction even if the magnet and the current are connected to a common support. This is by reason that the pressure wave has its own inertia and can be regarded as a separate entity, much as for a photon.  The Faraday motor as demonstrated uses a permanent magnet and a d.c. current in the rotor wire. The direction of rotation should remain the same if the direction of the magnetic flux from the magnet as well as the direction of current flow in the rotor wire are both changed simultaneously. Further, the direction of the pressure wave will also continue to be moving outwards. This may be an advantage from the standpoint of resonance where a strong impulse can cause a resonant circuit to ring in the form of a damped wave and if the circuit has low losses, the resonance will allow for the alternating current to continue without further input for an appreciable time. The frequency of resonance may be chosen to be equal to the f_MG frequency. Thus, the magnet can now be an electromagnet and capacitor arrangement.  Of a related note, here's a short video that shows a craft that may be based directly on the mechanics of the above analysis.  The vertical rods may be coaxial current elements and the magnetic field developed in a flat base coil. Notice the craft's rotation as the current elements follow the magnetic A vector (V_LM) field rotation.

Gravock

[broli]

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 .

[Magluvin]

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 .

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