Muller Dynamo

[xenomorphlabs]

Sounds good.
So you see the zero (magnetic) flux condition fulfilled when the 2 biasing magnets, the 2 coils and the rotor magnet all together add up their magnetic fields to zero for a short moment?

[chalamadad]

Sounds good.
So you see the zero (magnetic) flux condition fulfilled when the 2 biasing magnets, the 2 coils and the rotor magnet all together add up their magnetic fields to zero for a short moment?

How many biasing magnets depends on the coercivity of the core material. You can see this independently per coil. I see it fulfilled when the core is driven to saturation with the help of the magnets, yes. But it has to switch back and forth from saturated to almost saturated for constantly repeated flux change.

I called up a guy from a company selling cores. He told me he had hundreds of different materials and options. I guess I will have to try two or three differnt options. Coercivity needs to be low enough to get saturated at all but also you want flux to be large enough, so output will be max. I would think higher permeability is good but that is something we have to try.

Good luck everyone! I so hope this is going to work!!

[xenomorphlabs]

How many biasing magnets depends on the coercivity of the core material. You can see this independently per coil. I see it fulfilled when the core is driven to saturation with the help of the magnets, yes. But it has to switch back and forth from saturated to almost saturated for constantly repeated flux change.

I called up a guy from a company selling cores. He told me he had hundreds of different materials and options. I guess I will have to try two or three differnt options. Coercivity needs to be low enough to get saturated at all but also you want flux to be large enough, so output will be max. I would think higher permeability is good but that is something we have to try.

Good luck everyone! I so hope this is going to work!!

Have you considered Mu-Metal?
The effect should however manifest itself with "ordinary" ferrite as Romero did use ferrite and disadvised using steel or laminate.

[mondrasek]

I see a lot of good work had been presented since I last checked!

I was actually on the road the past two days and just got home yesterday with enough time to finish my “antenna” testing.  I had come to realize a couple things while away from testing and think I can explain what I have been seeing.  It may be important for others.

My “antenna” wire was hooked up like a “T” where the wire was the vertical line of the “T” and the horizontal line was going from a regulated DC supply as Vin to a BLDC motor drive circuit.  The center of the horizontal line had my current measurement resistor (.1 Ohm) and is where I attached the antenna.

I am fairly convinced that the antenna was a receiver.  For what would be transmitted by a single DC line?  So what was it receiving?  RF signals being blasted from the coils as they are effectively shorted by the Dump Cap once the virtual switching occurs.  At that moment the magnetic field in the coils should collapse and scatter the RF band.  Please correct me if I am wrong here.

So my antenna wire was picking up all the RF “noise” that was being broadcast by the coils under high load.  It was introducing that noise to my DC Vin to the BLDC drive circuit and effectively making for a very dirty DC supply.  The longer the antenna, the more noise and the slower/worse the motor drive circuit would perform.

So I will now try to shorten all my wires from my DC supply to the BLDC motor drive circuit.  Shielding might be appropriate, but what kind?  Wrapping in aluminum foil enough?  Or do I need coax?  Or ferrite core or toroid chokes?  Maybe just a low pass filter cap?  Any advice would be appreciated.

I believe a pulse motor drive circuit would be less susceptible to this RF noise.  But either way, all should take care to minimize the lead lengths of DC power lines.

When driving with a more conventional DC motor, appropriate motor RF noise shielding may be necessary.  In my case it will unfortunately limit my ability to take readings of input power with my existing equipment.

While cutting down my antenna I never got to an RPM that was as high as or higher than when not using the antenna.  But I distinctly remember noticing an increase in RPM when I first noticed my metering problems.  And I think I found it.  The rotor RPM increases when I meter the output load, not motor drive Vin.  So attaching an antenna to the Vout side may actually be beneficial.  I plan to test that out as well.

I also have an old tube radio.  I want to set it up next to the unit and see if it picks up noise and at what frequencies.

Also wondering if I can put a charge on a cap by wireless transmission if located close enough to the unit and wired to an antenna.  Maybe with a specific load and/or diodes?  Any ideas?

M.

[chrisC]

A thought experiment,

Imagine you have a core fixed in space, behind one end of that core at some distance you have a magnet with a pole face facing the core, fixed in space as well, now imagine that you have a moveable magnet facing the other end of the core with the same pole face facing the core, now imagine the stress the core sees as the moveable magnet approaches the core,, squish is what comes to mind for me,, now wrap a single layer coil around the core with a non resistive diode connecting the two leads together and imagine what happens to the winding as the moveable magnet approaches the core, as the flux change happens the coil will produce a field that is sync with one magnet and in repulsion to the other, ask yourself when does this induced field collapse.

Now take and wind another coil on top of the first one that is much bigger and goes through a FWBR into a cap.  When does the second coil produce current?  now instead of using a diode in the first coil take a 1\4 tap from the second coil, making sure that the 1\4 tap value is smaller than the first coil, and connect the first coil leads to that section.  Which coil can still produce current? what does the other coil see? when does this collapse?  What is the speed of the propagating magnetic flux that now gets to enter the core?

@webby1

Thanks for the thought provoking suggestions. I sure would love to experiment, unfortunately won't be able to spend time on the bench until September. I think if we can understand the effects, we will be able to make significant progress. Much appreciate your help. Keep them coming,

cheers
chrisC