Mostly Permanent Magnet Motor with minimal Input Power

[Magluvin]

Here is a closeup cutaway view. I made all this in Cinema 4D. Coil is shown in red, and the magnets is yellow. The magnets N pole is facing inward toward the coil.

Mags

[TinselKoala]

Thanks for your post TinselKoala.

Math is not my thing!... I have other talents.

I have a new test video uploading now but I can give you the results. So please help me and calculate how this test scores.

The Inductor weighs 115 to 120 grams. I can now lift it 1mm or more using a 0.272uf capacitor charged at 325vdc

How does this now score?

It could get better with stronger magnets but at this time this is all I have

I will post the new video demo as soon as it is ready for viewing

Thanks for your time and help

Luc

You're welcome, and you know I'm not knocking your efforts.

Here's what I get, running the energy in the cap against the potential energy of the lift.

You've lifted 120 grams by 1 millimeter, using a cap of 0.272 microFarad charged to 325 Volts.

Putting everything in mks units we have
0.120 kg lifted 0.001 meter using a cap of 0.000000272 Farad at 325 Volts.

The energy on the cap is
(CV^2)/2 ==  (1/2) x (0.000000272) x (325) x (325) == just under 0.015 Joule.

The energy of the lifted mass (gravitational potential energy, the energy it takes to lift the mass against gravity) is
(mgh) == (0.120) x (9. 8) x (0.001) == just under 0.0012 Joule.

(I usually just use 10 m/s^2 for g, the local acceleration due to gravity, but 9.8 is more correct if more difficult to calculate with. I've always believed that Earth's gravity was a bit light, anyway.... it should be one Standard G of 10 meters per second per second exactly.)

Now, you are almost certainly also fighting against friction and other drag forces like eddy current drag so it will actually take somewhat more energy to lift your mass a given height, but unfortunately these will also work against you in the other direction as well and so represent (probably unrecoverable) losses to the system. So you can say that it takes  _at least_  0.0012 Joule for your system to raise your mass, possibly much more. Ten times more, due to losses? So if your system actually expends ten times the GPE, or 0.012 Joule, to lift the mass .... that is still less than the 0.015 Joule that you started with in the capacitor.

I'm bad about decimal points, though. I've checked this a couple times and I still wind up with a dismal efficiency of around 8 percent, from cap energy to mass lift.

(ETA: I think the first way I'd try, to improve the energy transfer, would be to tune for  the "critically damped" condition. )

[TinselKoala]

You might also find this (long) document interesting.

http://www.coilgun.info/plim/braam_daniels_pulsed_linear_induction_motor.pdf

Apparently an efficiency of  8 percent is actually rather good for a coilgun/linear induction motor, which I think this basically is, only "inside out" .

Actually, I think the loudspeaker design's magnetic circuit is doing what I was trying to describe.

[Magluvin]

Here is a lil site that explains it also

http://hyperphysics.phy-astr.gsu.edu/hbase/audio/spk.html

It also shows how the coil can move in and out of the flux gap, and why I designed my speaker to always be in the gap, long strong(neo) gap

I have been searching for a while now. Only found a couple things so far on speaker motor design.  Makes me wonder what the big secret is. lol  Still looking.

I went through this back then also.

Mags

[conradelektro]

@microcontroller:

Your transformer-linear-motor is a clever idea. I like how you transformed a common component (a transformer and its coil) into a interesting experiment.

What were the results of your experiments and how far did you push your design?

Greetings, Conrad