Magneto-piezoelectric device

[NobleWolf]

We have two grade N40 neodymium magnets. The magnets are 1 inch long (along the X axis, horizontal),
1 inch wide (along the Z axis, into the page) and 0.2 inch thick (along the Y axis, vertical).
The magnets have a gap of 0.1 inch between them and they are in repelling mode (N-N or S-S).
The top magnet has 0 DOF (degrees of freedom) i.e. it can?t neither move nor rotate.
The bottom magnet has 1 DOF, it can only move along the X axis.

The bottom magnet starts at an horizontal offset (X axis) of 2.0 inches (between center of magnets)
to the left of the top magnet, and moves WITHOUT friction, from left to right, at 0.1 inch steps,
util it reaches an offset of 2.0 inches to the right of the top magnet (the bottom magnet travels
a total of 4.0 inches from left to right, in 40 steps of 0.1 inch each).



This movement generates attraction and repulsion forces between the two magnets.
The only force that can DO WORK (and require energy) is the force acting in the
same direction of movement i.e. along the X axis.

Here is a graphic showing the HORIZONTAL forces acting as the bottom magnet slides:



As you can see, the NET force is ZERO, and then, the NET work done is ZERO.
No input energy is required to move the magnet (remember that this is a FRICTIONLESS system).
I mean, we must put energy into the system to move the magnet from the far left side to
the center of the top magnet AND the system returns that SAME energy when the magnet
moves from center to the far right side.

The horizontal force is not the only one present in the system. Indeed, the real
force is not horizontal at all but at an angle, variable as the magnet moves along the path.
This horizontal force is just one of two components, result of decompossing the resultant
force (real) in its horizontal and vertical components.

Here is a graphic showing the VERTICAL forces acting as the bottom magnet slides:



So, there is a vertical force (or component) along the Y axis. This vertical force
CAN NOT DO WORK because the magnets can?t move in the vertical direction. Work is
force times distance. If distance is 0, work is 0.

The question is: ?Can we use this VERTICAL force to obtain free energy?

?What about attaching a couple of PIEZOELECTRIC SENSORS to the top magnet and
capturing the electric pulses generated by the push/pull of the vertical force?
?Can we take advantage of the horizontal force in the same way?
I mean, we can constraint the movement of the top magnet with piezoelectric sensors
located between the magnet and its enclosing case, like this:



Imagine a flywheel with its rotor mounted on a pair of PASSIVE magnetic bearings
(implemented with Halbach arrays) and enclosed in a vacuum chamber. When you start
this (almost) frictionless device, it can spin literally for years, WITHOUT LOAD.

The key concept is that we can collect the electric pulses from the piezoelectric
sensors, WITHOUT loading the flywheel.

The strain of a piezoelectric sensor is in the order of microns, and I think that
this small displacement of the magnet, do not affect the magnetic interaction between
rotor and stator, and the NET work done to rotate the rotor is still zero (or almost zero).

If the eddy currents generated are of concern, we can replace de neo magnets with
ferrite magnets (non electrically conductive).

?What do you think about this?. Your input will be very appreciated.

[gyulasun]

Hi NobleWolf,

I like your idea, it sounds good!

I am not familiar with utilizing voltage output from strained piezo devices. I know a piezo gas lighter can give several hundred volts of electric sparks to flame the gas on but what current it may provide I have no idea, have not studied it.

So I encourage you to go ahead towards practical testing!

rgds,  Gyula

[seymour85202]

I have a degree in electrical engineering but somehow in all those circuit design courses we just never got around to discussing how much a crystal deformed physically while interacting electrically with a circuit.  It just wasn't important to the purpose of the circuit.  But it obviously could be very important here.

So thus I find myself totally lacking in knowledge in what is actually happening in this particular configuration.  Heck, come to think about it, I don't even understand the physics behind how pressure on the crystal can generate the voltage.  A good link to a short explaination would be nice.

I seem to recall other weird devices/materials/configurations like the "Hall effect" that also might generate current or voltage from a moving magnetic field and I dont seem to recall any mention that they deform or provide any kind of back-EMF or interactive anti-magnetic resistance kind of force.

My expectation is that most people will guess (but not really know) that the small amount of crystal deformation will throw off your carefully constructed measurments/graph of a totaly static system.  The previously non-moving magnet is now slightly moving and thus behaving differently.  Thats gota be hard to get good measurments on.  The vibration is going to create some kind of sound (ultrasonic?) and/or heat, etc.   And people automatically associate sound with wasted energy just like friction and just assume that the spinning drum of magnets in a vacuume must somehow slow down - just because!

In you case,  I am not so sure.  I am not so quick to rush to judgment.  I just dont know.

You may be on to something here.  Keep up the good work.

[Blacksmith]

Seymour 85202
   This site has a few answers

http://www.globalspec.com/kistler/ref/tech_theory_text.htm

[NobleWolf]

Tank you for your encouragement.
I know that the (almost) frictionless passive magnetic bearing works good because of the work of Richard Post (electromechanical batteries). Those flywheels can rotate at 50.000 RPM and even more, they are not much bigger than a soda bottle (including the vacuum case) and, without load, they can spin for years.
Also, I know that if we have a rotor/stator pair made of permanent magnets, the only energy required to turn the rotor is the energy needed to overcome the friction (because the magnetic force is conservative).

I know that we can extract electrical energy from a piezoelectric crystal (see VIBES project, Vibration Energy Scavenging www.vibes.ecs.soton.ac.uk).

What I don?t know is if the energy extracted from this magneto-piezoelectric generator is OU or not.