Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: Mostly Permanent Magnet Motor with minimal Input Power  (Read 252397 times)

Neo-X

  • Sr. Member
  • ****
  • Posts: 379
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #105 on: February 18, 2013, 11:55:20 AM »
Opps wrong thread lol...  ;D

Khwartz

  • Hero Member
  • *****
  • Posts: 601
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #106 on: February 21, 2013, 10:48:10 PM »
Yes, you are correct!  but in this test the capacitor was connected long enough to discharge completely.

Thanks for your interest

Luc
lol, ok V2 = 0 Thanks for having confirmed. Cheer. :)

gotoluc

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #107 on: July 20, 2013, 06:42:44 AM »
Hi everyone,
 
I have been working on improving this motor design which I came up with some years back.
The idea of this motor design was to mostly use the flux of powerful Neodymium Magnets we now have, since in a standard magnet motor we would not get a power gain just by upgrading the old ceramic magnets to Neodymium Magnets, as we would also have to add more power to the motor coils to overcome the extra attraction force the Neo Magnets have.
However, in my motor design there is no sticky spot, so the more flux the magnets have the more mechanical power the motor has without changing the input power.
 
I have made a new video which demonstrates this and also demonstrates a better magnet and cores position which takes full advantage of both Permanent Magnet Poles and of the Electromagnet Poles.

This improvement basically double the mechanical output power of my first design without any increase to the input power.

The video should be self explanatory

http://youtu.be/-eTQ49RcFKM

Luc
« Last Edit: July 20, 2013, 05:35:16 PM by gotoluc »

gyulasun

  • Hero Member
  • *****
  • Posts: 4117
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #108 on: July 20, 2013, 10:19:05 PM »
Hi Luc,

Very good progress in getting higher and higher pulling force. Would like to suggest a "tuning method" unless you are also aware of it: just monitoring the coil's inductance on your L meter, you could easily see the effects of any changes in your setup, always aiming for higher and higher self inductance. For instance if you used two cube magnets on top of each other to double their length (I attached an edited picture from video to show it at one side) and this way you would also achieve a double distance between the coil and the side bars. Maybe you do not have enough cube magnets to do this for all the four directions at both main core ends but doing it with two bars, say, at the front and rear sides may show the effect if any.

I assume that the improvement in coil inductance (when you use a side bar to bridge the outer like poles, say South poles) comes from removing the "fringe" South pole flux from the coil area and direct them into the outside bar. I say this because seemingly you indeed close the magnetic circuit by using an iron side-bar but the magnets to be bridged being like poles they cannot close to any other pole in the bar because at the other end of the bar the same like pole enters the bar from the other end magnet.

So I assume that the increase in pulling force does come from the increased coil inductance and this inductance increase comes about by applying more flux from the permanent magnets, shifting the core's working point towards a higher permeability area of the B/H curve. Of course as you also mentioned in the video, there is an upper limit in increasing the flux by using stronger and stronger magnets: this upper limit is set by core saturation.

The possible ultimate core and magnet shape for your setup would be to use a cylinder  core (say a ferrit rod) in the middle (on which also a cylinder coil would slide) and use a ring magnet at both core ends with its ID matched to core's OD and then use a soft iron tube (with certain wall thickness) outside instead of the bars to connect the ring magnets' outer like poles. No stray flux would escape from such setup.  8)

Thanks, Gyula

Khwartz

  • Hero Member
  • *****
  • Posts: 601
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #109 on: July 21, 2013, 12:57:38 AM »
Hi gotoluc!

Thanks for sharing your very valuable experiments.

I see very brillant your use of bacefm as an alternative drive synchronized with the moving of the coil.

You can use imho this as a very interesting piston motor; a "motor" indeed. But true you can drive a generator and try to find the limit of efficiency of the system.

But before to do so, could you scientifically and rigorously measuring the power output of it? Could you add a pouly with a baril, a wire, a mass, and measure the time your motor will pull the mass up to 1 meter? This giving us the effective mechanical output power to compare to the electrical power. A graphic of the evolution of the mechanical power in function of the electrical power input would be a very must; imho.

Cheer, Khwartz.

gotoluc

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #110 on: July 21, 2013, 06:11:51 AM »
if you used two cube magnets on top of each other to double their length this way you would also achieve a double distance between the coil and the side bars may show the effect if any.

If you increase the air gap (distance) between the outer surface of the coil and outer core, the result will be a drop in pull force, even though you double the magnets. As the outer cores and coil can do as much work as the inner core and coil. So the closer to zero air gap will give the best results.

I assume that the improvement in coil inductance (when you use a side bar to bridge the outer like poles, say South poles) comes from removing the "fringe" South pole flux from the coil area and direct them into the outside bar. I say this because seemingly you indeed close the magnetic circuit by using an iron side-bar but the magnets to be bridged being like poles they cannot close to any other pole in the bar because at the other end of the bar the same like pole enters the bar from the other end magnet.

The increase in the coils inductance comes from adding iron core close the the surface area of the coil. As you should know, the closer the copper wire to the iron the more the inductance gain.
I cannot close the loop between the inner and outer core (like a transformer) as this would short out the north and south flux and the coil would barely move. I know this because I tried it. I thought it would boost the inductance big time, and it did but the coil also barely moved.

So I assume that the increase in pulling force does come from the increased coil inductance and this inductance increase comes about by applying more flux from the permanent magnets, shifting the core's working point towards a higher permeability area of the B/H curve. Of course as you also mentioned in the video, there is an upper limit in increasing the flux by using stronger and stronger magnets: this upper limit is set by core saturation.

You may think that the extra pull force is from an increase in Inductance but that is not correct. I'm sure there is a small increase caused by the inductance boost but the most of the extra pull force is from the outer coils opposite pole working on the outer core and magnet pole just like the inner coils pole working on the inner core and magnet pole. I can prove this by making the coil move the same just using outer cores and magnets with no inner core and magnets. The only thing it's just the opposite pole.
I don't know if you follow me. I've been trying to tell about this before but people are not picking up on it.
A coil produces the opposite pole half way through its thickness. Just like a one inch thick magnet will have 1/2 inch of North and 1/2 inch of South.  Well, a coil that's wound one inch thick will also do the same.
I have experimented with this some years back and I though this was known.  Is it not known this way?
Do you understand what I'm trying to explain?


The possible ultimate core and magnet shape for your setup would be to use a cylinder  core (say a ferrit rod) in the middle (on which also a cylinder coil would slide) and use a ring magnet at both core ends with its ID matched to core's OD and then use a soft iron tube (with certain wall thickness) outside instead of the bars to connect the ring magnets' outer like poles. No stray flux would escape from such setup.

I don't know about that. How can a cylinder work better the what I just demonstrated?... also, doesn't a ferrite loose inductance when you apply magnet flux?

Thank you Gyula for always asking important questions and sharing your knowledge.

Luc

gotoluc

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #111 on: July 21, 2013, 06:33:42 AM »
Hi gotoluc!

Thanks for sharing your very valuable experiments.

I see very brillant your use of bacefm as an alternative drive synchronized with the moving of the coil.

You can use imho this as a very interesting piston motor; a "motor" indeed. But true you can drive a generator and try to find the limit of efficiency of the system.

But before to do so, could you scientifically and rigorously measuring the power output of it? Could you add a pouly with a baril, a wire, a mass, and measure the time your motor will pull the mass up to 1 meter? This giving us the effective mechanical output power to compare to the electrical power. A graphic of the evolution of the mechanical power in function of the electrical power input would be a very must; imho.

Cheer, Khwartz.

Thanks for your positive comment.

The coil weight is 100 grams. I can place it vertically (against gravity), power it and calculate the amount of mm it moved up in x amount of time using x amount of watt.

Would that work?

Or much easier for me is a capacitive (joule) discharge and tell you how many mm it moved up.

Luc

gyulasun

  • Hero Member
  • *****
  • Posts: 4117
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #112 on: July 21, 2013, 01:05:58 PM »
Hi Luc,

Quote
If you increase the air gap (distance) between the outer surface of the coil and outer core, the result will be a drop in pull force, even though you double the magnets. As the outer cores and coil can do as much work as the inner core and coil. So the closer to zero air gap will give the best results. 

Okay, I accept that and although it is irrevelant now, I think you have tested how the coil inductance changes when you increase the air gap and found the inductance increases in a lesser extent compared to a previously smaller air gap? I mean you measure 867 mH for the coil with the single magnets at the ends (when there is no bridging bar between the outer like poles) and then you apply the bridge and get 942 mH.
Then you double the air gap for the bridge by using double magnets (i.e. doubling their thickness) and you measure also an increase in inductance with respect to the no bridge 867 mH value but now this measured value would not reach the 942 mH value received for the previous smaller air gap case, so this is what I figured.
Because you measured the pulling forces for the different cases, obviously the size of the air gap has a much stronger influence on the force than the increase in inductance does.

Quote
I don't know if you follow me. I've been trying to tell about this before but people are not picking up on it.

Well I follow you but this time I did not revise your years ago tests on this setup, sorry. Yes, a coil will also have a Bloch wall in its middle part just like a permanent magnet does, no doubt on that.

Quote
I don't know about that. How can a cylinder work better the what I just demonstrated?... also, doesn't a ferrite loose inductance when you apply magnet flux?

Well, a cylinder coil in itself would not work better than your rectangular coil (assuming equal inductance and number of turns) but I meant also using ring magnets instead of the cube magnets. I simply thought of occupying all the space around a cylinder coil by having covered it all around by a ferromagnetic tube to replace the bars (in fact you would have an infinite number of "bars" from the generatrix of the cylinder tube), this way the opposite poles could be utilized the most from the coil.
Now I looked for radially magnetized ring magnets (i.e. their ID is say North all inside and their OD is South all around outside) which would be needed for my suggestion but unfortunately such is not manufactured...  can only assembled from arc magnets like is shown here: http://www.supermagnetman.net/product_info.php?products_id=380  or also could be assembled from say smaller cube magnets also wrapped up in an enclosure. Understand now what "cylinder" setup I mean? Of course such setup would cost more to assemble than your present one and I also prefer initial testings with a cheap solution, I just indicated an 'ultimate' setup in this respect.
Regarding a ferrite loosing inductance when influenced by (strong) outside magnets, yes it normally does, mainly when cross section area is small versus the flux strength, I mentioned ferrite as a first straigthforward thought for cylinder shaped cores...

rgds, Gyula

gotoluc

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #113 on: July 21, 2013, 03:24:39 PM »
Hi Luc,

Okay, I accept that and although it is irrevelant now, I think you have tested how the coil inductance changes when you increase the air gap and found the inductance increases in a lesser extent compared to a previously smaller air gap? I mean you measure 867 mH for the coil with the single magnets at the ends (when there is no bridging bar between the outer like poles) and then you apply the bridge and get 942 mH.
Then you double the air gap for the bridge by using double magnets (i.e. doubling their thickness) and you measure also an increase in inductance with respect to the no bridge 867 mH value but now this measured value would not reach the 942 mH value received for the previous smaller air gap case, so this is what I figured.
Because you measured the pulling forces for the different cases, obviously the size of the air gap has a much stronger influence on the force than the increase in inductance does.

Well I follow you but this time I did not revise your years ago tests on this setup, sorry. Yes, a coil will also have a Bloch wall in its middle part just like a permanent magnet does, no doubt on that.

Well, a cylinder coil in itself would not work better than your rectangular coil (assuming equal inductance and number of turns) but I meant also using ring magnets instead of the cube magnets. I simply thought of occupying all the space around a cylinder coil by having covered it all around by a ferromagnetic tube to replace the bars (in fact you would have an infinite number of "bars" from the generatrix of the cylinder tube), this way the opposite poles could be utilized the most from the coil.
Now I looked for radially magnetized ring magnets (i.e. their ID is say North all inside and their OD is South all around outside) which would be needed for my suggestion but unfortunately such is not manufactured...  can only assembled from arc magnets like is shown here: http://www.supermagnetman.net/product_info.php?products_id=380  or also could be assembled from say smaller cube magnets also wrapped up in an enclosure. Understand now what "cylinder" setup I mean? Of course such setup would cost more to assemble than your present one and I also prefer initial testings with a cheap solution, I just indicated an 'ultimate' setup in this respect.
Regarding a ferrite loosing inductance when influenced by (strong) outside magnets, yes it normally does, mainly when cross section area is small versus the flux strength, I mentioned ferrite as a first straigthforward thought for cylinder shaped cores...

rgds, Gyula

Hi Gyula,

from what I read above you're understanding everything perfectly well.

I also now agree that if you could find a radially magnetized ring magnet then the cylinder setup would probably work best. However, we also need to keep in mind that the coil would need to be held by guides if one wants to use the mechanical movement of it. So the outside cylinder would need to be two halves with a slit of the thickness of the material holding on to the coil.

To improve on outer surface area loses what I was thinking of doing for my next super build is making the center core 1/2" to 3/4" thick but 6 inches wide. That way 90% of the outside coil surface can be covered and converted to power.

The only thing I don't know about is the ideal coil wire size, length, amount of turns and resistance (combination of all) to obtain the most pull per watts.
If you know of a way to calculate that would be of great help.

Thanks for sharing.

Luc

Khwartz

  • Hero Member
  • *****
  • Posts: 601
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #114 on: July 23, 2013, 03:19:31 AM »
Thanks for your positive comment.

The coil weight is 100 grams. I can place it vertically (against gravity), power it and calculate the amount of mm it moved up in x amount of time using x amount of watt.

Would that work?

Or much easier for me is a capacitive (joule) discharge and tell you how many mm it moved up.

Luc
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.

gotoluc

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #115 on: July 23, 2013, 05:22:07 AM »
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

  • Hero Member
  • *****
  • Posts: 509
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #116 on: July 24, 2013, 02:11:29 PM »
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

  • Hero Member
  • *****
  • Posts: 601
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #117 on: July 25, 2013, 11:17:08 PM »
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

  • Hero Member
  • *****
  • Posts: 4117
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #118 on: July 26, 2013, 12:40:57 AM »
...
 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  (Js ~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

  • elite_member
  • Hero Member
  • ******
  • Posts: 3096
Re: Mostly Permanent Magnet Motor with minimal Input Power
« Reply #119 on: July 26, 2013, 05:25:03 AM »
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