Mostly Permanent Magnet Motor with minimal Input Power

[gotoluc]

Here is the link to the best result I can do with the supplies I have available. To do any better I would need stronger magnets. If that is the case then it will have to wait on my return to Canada.

Link to new video: http://youtu.be/qaNYSroHuak

Please note that you may not be able to see the 1mm+ lift of the coil on the video after its been compressed and all. However, I'm sure my word should stand good that it is indeed lifting 115+ grams

Luc

[Lakes]

Interesting Stuff Luc, did you make those laminations yourself?

[DeepCut]

Hi Luc.

I've stuck the maths in a spreadsheet for you.

Here is the Microsoft Excel version :

http://internut.webspace.virginmedia.com/Lucmotor%20Efficiency%20Test%20-%20Capacitor%20Version.xls

Here is the Open Office version :

http://internut.webspace.virginmedia.com/Lucmotor%20Efficiency%20Test%20-%20Capacitor%20Version.ods


All the best,

DC.

[Magluvin]

Just some casual thoughts from an innocent bystander.....

I'd probably try this: a ferromagnetic or soft ferrite coil core that is a hollow cylinder, and a non-magnetic axis for the core to slide on, like an aluminum or plastic rod. I think a lot of flux is being wasted or channelled into parts where it's not doing useful work.

Also.....I think I'd like to achieve "critical damping" in the discharge waveform. That is, one doesn't want ringing, one wants all the cap's energy dissipated into the coil in the first cycle of the "ring". This requires tuning inductance and capacitance together. Diodes will stop ringing but at the cost of dissipating energy where it can't do useful work. You get the most "bang" for your buck if you can dump all the cap energy into the load in the first cycle without any coming back or voltage reversal: the critically damped waveform.

Stefan's math up above looks more complicated than it is. Don't forget "significant digits".... you can safely ignore all but the three leftmost digits in all of those numerical results, because they represent false precision and are certainly wrong,  anywhere except inside the calculator. If you measure 28.7 volts on a 0.3 microFarad capacitor.... which probably has a 20 percent tolerance in its value anyway...... your answer is NOT going to have six or seven meaningful digits, so there is really no point at all in regurgitating them from a calculator display... because they are just wrong (remembering the tolerance in the component's value).
So the energy on a capacitor in Joules is one-half of the Capacitance in Farads, times the square of the Voltage in Volts (this is why higher voltages are better than higher capacitances, usually).  The energy in Joules required to lift a mass (in kilograms) to a certain height (in meters) is just the mass times the height times the local gravity acceleration. If you avoid false precision and just use the digits you are sure of, it is easy to compare the results of the two calculations.

Ok, I'll go back to lurking quietly now.
Go for it, Gotoluc !

Im not sure I agree with the first statement above.  The magnets applied to the top and bottom of the core are same poles facing the core. If you know how typical speaker technology, the magnets fields are not inline with the voice coil. They are "directed" to be from the inner side of the coil to the outer of the coils circumference.

So Lucs inner core with N facing in on top and on the bottom, those are repelling fields.
Those fields N will be directed outward from the central core. All along that center core are north fields outward, perpendicular to the core, looping back around to the south poles at the top and bottom.

Then you add the outer cores amd the path for thos outward N fields become more concentrated because the loop cannot expand outwards to get to the south. The outer cores help contain and direct the fields, very similar to a speaker voice coil and magnet structure.

So basically Luc, If you want to enhance your knowledge greatly with your project, study speaker design. Or more to the point, high power sub woofer design.

There are special speaker designs that will interest you also is a planar speaker design with a spiral coil on a diaphragm between 2 flat disc magnets with lots of tiny holes for the air pressure(sound wave) to pass through the front and the rear. Pioneer made a very nice set of headphones using the planar method years ago. And the disk magnets were same pole facing in, like your setup. The bass reproduction from those headphones was UnReal.

So dont think about the coil being attracted and repelled by the magnets at the top and bottom, but how the coil reacts to the fields escaping outward all along the central core.
The coils powered interaction to those fields lines perpendicular to the core is what is really going on. If you remove the core, or replace it with a non magnetic one, your output will not be better. It will be an inefficient speaker in comparison.

And, I dont believe there is any ring happening when Luc discharges the cap into the coil. It actually is taking a good amount of time for it to totally discharge from high to low then nadda.  Electrolytic caps dont provide a good oscillating environment anyways.
Try it, its not very good at all.

Luc,  look into the speaker and high power subwoofer design that can be found. There is not as much as you might think. Not for people like us anyways. There is a program out there that allows you to design speakers in a cad environment. You can design the cores, magnets and the rest any way you want. I have to look the name up as it was years ago that I have looked into the subject.   Google books has some good old stuff also. ;]

here is a sub woofer design I had made near 15 years ago. The key features were shallow depth with longer throw, elimination of the lower spider suspension by utilizing a second inverse rubber surround of which helps to keep the cone and coil on axis.

Earthquake audio company got it out before I did with the dual rubber surround suspension eliminating the spider and reducing depth. 

The magnets in the magnet housing are N facing inwards to the center and S outward to the outer core. Alumapro conquered that part of it soon after.

I just couldnt get the funding to break it out at the time. too little too late

[wings]

related to this effect:


http://science.net84.net/magnetic-generators/generatorY.html