Mostly Permanent Magnet Motor with minimal Input Power

[gotoluc]

You're wellcome! Luc.

I have thought this possibility to put vertical the axis and work against grativity but if it very easy to realize, it is not so easy to have an enough accurate time measurement on so short period of time.

The formula any way is: P[W] = M[kg] * g[m/s2] * L[m] / T.

Cheer.

So then, how about a capacitive discharge against gravity and just measure how many mm the 100 grams traveled up.

Luc

[tim123]

Hi Luc,
  I've been working on a very similar design to yours, and I've written some PHP code to do all the calculations. I'd be happy to discuss / share it with you - send me a PM...

hartiberlin is correct - you have to go bigger to get OU... But once you do get over a certain size - then this design does go overunity...

You need a much bigger coil, with fatter wire. To optimise the coil you need the most amp turns per ohm of resistance possible - and that is limited a) by coil physical size, and b) the resistivity of the conductor material.

Magnetic Field Strength (H) = Number of Turns * Amps / Coil Length

BField (In Tesla) = H * Permeability (of iron / vacuum whatever)

You also need a bigger face-area (Area) for the core...

Magnetic Pull (newtons) = (BField * Bfield) * Area / 2 * u0

Even though it should be OU, there are still 2 main flaws with this design, as far as I can tell:

1) You're limited by the strength of the PMags. The best neodymium is less than half as strong as saturated electric steel (.5T vs 1.6T). It looks like an optimised plain steel solenoid would outperform your design, when running at full power. (Whereas your design is better at low power - below saturation). Also, I think I'm right in saying that you can't saturate iron with any permanent magnet - none are strong enough.

2) Your piston is effectively 'pushing' against the H-field of the core - which is extremely weak compared to the B-field of iron. There are ways round this - but you'd have to change the basic design.

Hope this helps.
Tim

[Khwartz]

So then, how about a capacitive discharge against gravity and just measure how many mm the 100 grams traveled up.

Luc

So far, at least mathematically it is in both cases energy measurement. So it could worth the try in a first stage; i.m.o.

Cheer, Khwartz.

[gyulasun]

...
1) You're limited by the strength of the PMags. The best neodymium is less than half as strong as saturated electric steel (.5T vs 1.6T). It looks like an optimised plain steel solenoid would outperform your design, when running at full power. (Whereas your design is better at low power - below saturation). Also, I think I'm right in saying that you can't saturate iron with any permanent magnet - none are strong enough.

2) Your piston is effectively 'pushing' against the H-field of the core - which is extremely weak compared to the B-field of iron. There are ways round this - but you'd have to change the basic design.
...

Hi Tim,

Welcome to this forum. 

Would like to understand your points above. 

1) You mean the core for the coil should be made from electric steel?  If yes, have you considered possible eddy current losses in it (even though the pulsing frequency would be less than 10-15 Hz or so, I assume)  or this possible loss could be minimized by using laminated electric steel plates? 
I read on Wiki https://en.wikipedia.org/wiki/Neodymium_magnet#Description  that  I quote: "the tetragonal Nd₂Fe₁₄B crystal structure ... has  a high saturation magnetization  (J_s ~1.6 T or 16 kG) and typically 1.3 Teslas." 
Does this mean that now there are Neo magnets with > 1Tesla saturation?

2) Could you elaborate some more how to change the basic design to get more B filed involved if I got it correctly.

Thanks,
Gyula

[gotoluc]

Your piston is effectively 'pushing' against the H-field of the core - which is extremely weak compared to the B-field of iron. There are ways round this - but you'd have to change the basic design.

Hope this helps.
Tim

Hi Tim, thanks for your post and details.

Like Gyula I would also like know more on a design like you mention above.

Please share you ideas

Also, not sure I understand the term "electric steel"

Thank you

Luc