47000 Watt Magnetizer

[tinman]

Well, axially magnetized means relative to your diagrams the main flux through the thickness of the rotor will be horizontal.  Likewise, the return flux above and below the rotor will be horizontal.  Obviously this is a big simplification.  That means that the horizontal flux lines will be cutting across your pickup coils at about 90 degrees - the pickup coils are on a vertical axis in your diagram.  If you have changing flux that is purely horizontal and the pickup coils are vertical then the coils will pickup nothing.  Therefore your pickup coils will pick up relatively little changing flux and thus generate relatively little EMF and have a limited available output power.

I see no reason why the pickup coils will not see a changing magnetic flux,and a good one at that.
In fact,i will put together a quick demo tomorrow night,and we will see if sliding a magnet across an inductors core(with an air gap of course)back and forth produces a good EMF in that inductor.
I have not tried it yet,but my guess is that the core will carry the field that is under it just as good as it would with a magnet passing by it-as in a normal generator setup.

[picowatt]

I see no reason why the pickup coils will not see a changing magnetic flux,and a good one at that.
In fact,i will put together a quick demo tomorrow night,and we will see if sliding a magnet across an inductors core(with an air gap of course)back and forth produces a good EMF in that inductor.
I have not tried it yet,but my guess is that the core will carry the field that is under it just as good as it would with a magnet passing by it-as in a normal generator setup.

Tinman,

Have you considered machining a pair of elliptical pole pieces angle mounted to your shaft with a neo ring magnet positioned between those pole pieces in lieu of making and magnetizing a custom shaped magnet?.

As for your "47000 watt magnetizer", it all sounds a bit scary.  Welded contacts and melted aluminum aside, you must also ensure that the current thru the magnetizing coil and lead wires does not "ring down".  Polarity reversals during a ring down can partially demagnetize the previously achieved peak magnetization levels.

If you are bound and determined, consider charging a bank of capacitors via a current limiting resistor and then dumping that cap bank across your coil.  Even a few hundred milliseconds of activation is way more time than needed to flip domains.   

PW   

[MileHigh]

I see no reason why the pickup coils will not see a changing magnetic flux,and a good one at that.

Really?  Look at my chicken scratchings.  What do you think about my marked up drawing?

[DreamThinkBuild]

Hi Tinman,

I wonder if the coging was due to the fact that your magnet was not shaped so as the outer perimeter was always level with the core of the coil's like mine will be?.

Yes, the design crossed the plane so that the magnets pole was angled toward the stator. This also introduced Lenz when loaded, it was not efficient.

Your design stays within the edge boundary of the magnet which would be interesting to see the difference.

[citfta]

Hi Brad,

Some good news to support your idea for a wobble magnet generator.  I built a very crude version just to test the concept.  This is just a single ceramic ring magnet with north on one side and south on the other.   As you can see in the picture I am just swiping the magnet back and forth across the core of the coil.  Without the coil at all on the test stand the motor was drawing 1.8 amps after giving it some time to warm up the bearings and get loosened up a bit.  When I added the coil without any load the current only went up about .01 amps so the side to side motion of the magnet appears to be giving very little cogging effect.   The open voltage on the coil was only 6 volts but of course there is only one magnet and it was only turning about 1320 rpm according to the frequency as calculated by my scope.  When I loaded the coil with a 30 ohm load the current did not change going to the drive motor.  My voltage did drop to about 2.4 volts but I expected a pretty good drop because of the speed of the rotor and the fact I am only using a single ceramic magnet to excite the coil.  When I shorted the coil the current to the motor only went up .01 amps.  I expect this may be because of the slow speed of the rotor.  I have heard many times the higher speed on the rotor helps to overcome the lentz effect.  I am very interested to see how your larger build with good magnets will perform.  I would like to pursue that idea myself if I can get all the parts together to see what it will do.

Take care and keep up the good work and ideas.
Carroll