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: Very practical magnetic asymmetry  (Read 7712 times)

dieter

  • Hero Member
  • *****
  • Posts: 938
Very practical magnetic asymmetry
« on: February 22, 2014, 10:07:32 PM »
Just something to think about. I have to say, even although I think this is explained by the distribution of force over a longer way, in a very practical way, from the point of view of a human being, this is clearly an asymmetric  feature. If I compare the force required this way and the direct way, to just lift it off. This tremendous attraction may accellerate a greater mass I think. It may have something to do with the twist and the arc shape of the field.


dieter

  • Hero Member
  • *****
  • Posts: 938
Re: Very practical magnetic asymmetry
« Reply #2 on: February 23, 2014, 03:59:00 PM »
You're comparing apples and oranges...


I highly respect James Roney's efforts and that he explained how it's made, but...


He says he cuts off the magnetic field at a certain position, but in fact he just shields it, aka redirects it and compresses it in the inner sheetmetal layer. You cannot cut off a magnet field. Shielding will not cut off a single fieldline, and each fieldline is a closed loop. The attracted object wants to reach the point of highest fieldline density (besides to align its shape to support the field axis), and when it reached this point of max fieldline density (usually a pole), it had to penetrate a certain exact number of field lines. To be removed from the attractor means to go back trough the same number of lines, where it does not matter (and that's the point) how dense these lines now are! The formula of "a magnetfield is getting weaker in square with the distance' is not valid when shielding is used, nonetheless, the number of field lines is the same, be it in 2 inch air or in a 1/16 inch iron shield. And what goes bejond the lines, must come out of the lines, unless there's a button to turn off the field...
101 magnet theory, that needs to be understood.


But indeed, there is more. Like, when the polarity suddently changes, then this rule is broken.
 

nwman

  • Sr. Member
  • ****
  • Posts: 308
Re: Very practical magnetic asymmetry
« Reply #3 on: February 23, 2014, 09:42:15 PM »
One of the tricky illusions of magnets if how much work is done to attract and pull away magnets in different directions respectively. In simplest terms you always have to physically test the magnets interactions. The equations of attracting magnets is only for magnets with opposite poles aligned. If you change the angles then the equation is no longer is correct and is difficult to calculate. You have to test and measure.  You have to use the basic Work = Force x Distance.


So if two magnets are attracting N-to-S then the equations is "close to" the basic inverse square law. Thus the attraction gets stronger in a nice exponential curve as they approach each other. Figure 1


However, if you then try to remove the magnets by sliding them apart at a 90 degree angle it seems like it takes half the force needed to slide them off...... Well, that is true*. It does take half* the force. Figure 2. But the force is only half the battle... equations. The other half is distance. As you pull the magnets apart the force needed increases until the halfway point of both magnets when it reaches it's strongest. Then it ramps down quickly.


Figure 3 shows both force vs. distance graphs overlapped. If you add together both the "areas" of both curves you "should" come out with equal numbers. Thus showing the same amount of work has been done. Just under different conditions.


That is the theory at least.


I'm currently working on retesting some data the shows more work is actually needed to slide magnets apart at 90 degrees then is needed to pull them apart at zero degrees (straight apart). It seems backwards but I physically tested the below arrangement with "different shaped" magnets. I plotted the data and found (in simplest terms) that if two magnets attracting at zero degrees and generated 1 unit of Work it would take 1.55 units of Work to slide them apart at 90 degrees. Thus, if you were to revers the action and have the magnets attract at 90 degree (creating 1.55 units of work),  and only 1 unit of work to pull them apart at zero degrees then you end up with .55 units of work OU! (NOTE: magnets never touch so no friction when sliding.)


 I have to be over looking something.


nwman

  • Sr. Member
  • ****
  • Posts: 308
Re: Very practical magnetic asymmetry
« Reply #4 on: February 23, 2014, 09:46:25 PM »
Sorry, I made the graph wrong. This is more like what I found with two .5" square neo magnets.

dieter

  • Hero Member
  • *****
  • Posts: 938
Re: Very practical magnetic asymmetry
« Reply #5 on: February 23, 2014, 10:34:24 PM »
Sounds good, go for it!  8)


Meanwhile I wonder: What defines the force that is required to turn the magnet when it sticks on an other magnet ... note, idea, two mechanicly linked magnets in parallel, out of magnetic influence by eachother, but near other magnets, one alligned to the field, the other reverse, cancel eachother out, so now to alter their polarisation, while they are attracted by other magnets,  no force is required... now it's me who must have made a mistake somewhere...

nwman

  • Sr. Member
  • ****
  • Posts: 308
Re: Very practical magnetic asymmetry
« Reply #6 on: February 23, 2014, 10:42:19 PM »
Sounds good, go for it!  8)


Meanwhile I wonder: What defines the force that is required to turn the magnet when it sticks on an other magnet ... note, idea, two mechanicly linked magnets in parallel, out of magnetic influence by eachother, but near other magnets, one alligned to the field, the other reverse, cancel eachother out, so now to alter their polarisation, while they are attracted by other magnets,  no force is required... now it's me who must have made a mistake somewhere...


Sorry, but you'll need to draw this out.

dieter

  • Hero Member
  • *****
  • Posts: 938
Re: Very practical magnetic asymmetry
« Reply #7 on: February 23, 2014, 10:51:29 PM »
Maybe that's not neccessary, I just realized, when 2 Magnets mechanicly cancel out eachothers axial alignement forces, then they also cancel out attraction and repulsion and are therefor useless. Got to rethink this on occassion.

nwman

  • Sr. Member
  • ****
  • Posts: 308
Re: Very practical magnetic asymmetry
« Reply #8 on: February 23, 2014, 10:55:34 PM »
In regards to the first post and pictures:


You need to measure the attraction force over distance of the two magnets coming together directly. = 1 unit of work.


Then,



You would need to measure and graph the force needed to spin the magnets over the 90 degrees of rotation (note length of lever) to calculate work preformed. And then also the force needed to slide the top magnet off over the distance needed to have near zero attraction force. This would calculate total work needed to remove the magnet given your approach.


Then subtract the two and see what you get!


 I always account for at least 10% margin of error. If it makes 1 unit of work to attract and  .9 units to remove I would say it's still probably in unity. If it makes one unit of work to attract and .5 units to remove then I would retest several times to confirm and you might have something!


dieter

  • Hero Member
  • *****
  • Posts: 938
Re: Very practical magnetic asymmetry
« Reply #9 on: February 24, 2014, 02:58:31 AM »
I absolutely agree with the distance thing. And when it comes to efficiency, I often see people like "crap, only 99%" where I tend to build "superefficient stuff" based on ideas, that then turns out to be extremly inefficient  ;D