Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Perendev Magnetic Motors

  1. Dec 11, 2005 #1
    I figured this would have been talked about before, but i couldn't find it in search.

    I know its not defying any real laws or anything and theyve been around forever, but im wondering if anyone knows any info on them.

    What sort of HP/Torque can they produce?
    What magnitude of stray B field is there?

    Why are they not researched as much? Limited supply of natural perm-magnets?
  2. jcsd
  3. Dec 12, 2005 #2

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That is correct.

    Also from the link
    But look, Howard Johnson did it twenty-five years ago! Unfortunately, his also was not quite ready for market...yet.


    The same scams are used over and over again.
    Last edited: Dec 12, 2005
  4. Dec 12, 2005 #3

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Okay, we have a request for the proof of this. As I recall it is a direct consequence of the fact that the divergence of the field is zero... If anyone else remembers this proof, please post. Otherwise, I will try to dig it up later, but I may or may not remember how to do this.

    The thread is open for the proof to be posted.
    Last edited: Dec 12, 2005
  5. Dec 12, 2005 #4
    I wrote a nice long post in response to the OP last night and when I went to hit the submit button, I found a small, grey being had locked the thread.

    Today all I want to say is that Howard Johnson wasn't a scam artist but a kind of bumbler who fooled himself. His motor worked if, and only if, he was holding the "pusher" magnet in his hand. He tried a couple times to mount that magnet but couldn't seem to position it correctly. It turned out, of course, that he was providing the motive power himself by moving the magnet he was holding back and forth. He was fully aware his hand was moving back and forth but he thought the rotor magnets were pushing his hand away and all he was doing is putting it back into position. Someone had to explain to him what was going on and why he couldn't get it to work when he mounted the magnet. Once he realized his mistake, he stopped work on it.

    He showed a working model to the patent examiner, one where he held the pusher magnet in his hand, and the examiner didn't realize what was going on either, so Howard wasn't alone in his folly.
  6. Dec 12, 2005 #5

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Sorry, I guess I shouldn't have locked the thread.
  7. Dec 13, 2005 #6

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It should also be noted that at face value the second law excludes the possibility of a self-powered, permanent magnet motor, but even if we assume that the magnets somehow acquire their energy from some unseen and previously untapped supply, there is a proof from Electrodynamics that no configuration of permanent magnets could work. Hopefully someone will get me off the hook by posting the proof. :biggrin:
  8. Dec 13, 2005 #7
    The main thing that I understand which makes it impossible, is that the field of a permanent magnet is a static force, just like gravity.

    The field around a PM is always at the same strength. Therefore it is no different than an invisible rubber ball. If two magnets push away from each other, it's only because someone has first pushed them together.

    Two unlike poles attracting are like two objects with a stretched rubber band between them. The pull toward each other always exists, even when friction prevents it from acting. Here again, to trigger them to move, you have to do the work to get them close enough to overcome friction. That's a one shot deal. Once together, they don't move apart on their own. Work has to be done by an outside agent to set the situation up again.

    If PM's only blinked on and off by themselves we could make a motor in a second. As it is, their fields are static, and no more a source of energy than a rubber ball would be.
  9. Dec 19, 2005 #8


    User Avatar
    Science Advisor

    This looks a lot like something we discussed in the engineering section, porbably a year ago or so...It was at the same stage then too. Some german company was tooling up to start production.
  10. Dec 19, 2005 #9

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There is a formal proof from E&M, but since I don't remember how to do it, and since it doesn't seem to be in my old E&M book [by Jackson], I'll have to try to find it in my old notes.
  11. Dec 21, 2005 #10
    Yea, i cant think of what it would be other than something like computing work done to move a magnet to a position with reference to another magnet is equal regardless of paths (work in=work out), but in my mind that doesnt seem to work if youre somehow able to shield or shape the magnetic field. But if you were able to seriously "shield" a magnetic field, or even shape it so that the work done to move it into a position where there is a potential gradient away from the magnet greater than the path from which you came... I don't know. I know its something simple like Del dot B = 0 that proves this, but im not sure why.

    I think ill try to do a mathematical model of this system and see it if works. I havent done fields in a while, but the magnetic properties of a material lie on its surface right? makes sense since the dipoles would cancel out internally.

    But to do this, and to answer my previous curiosity, what does the force/potential field look like on the sides of a magnet? if you were to break apart a magnet into squares on the surface, on the side from the N to S is it a gradual change or a quick step?

    Its hard not to think of E field properties when dealing with B fields.
  12. Dec 21, 2005 #11
    I'm not sure what you're asking, but recall that the field of a permanent magnet is exactly the same as the field of a loop of current carrying wire. If you first envision the field around a straight current carrying wire and understand how there is a direction inherent in that field, at right angles to the direction of current flow, and then imagine forming that wire into a loop, you'll be able to see where the apple shaped magnetic field comes from, and the "direction" things want to take when in that field. It's convenient to think of the field as emerging from one end, bending around and re-entering the other end.
  13. Dec 21, 2005 #12
    Yea, thats probably what makes the most sense in my mind, but im trying to find out what would make the most sense for a mathematical model with the magnet not being a close-to-point dipole.
  14. Dec 21, 2005 #13
    Still not sure what you are trying to figure out.

    Just for good measure here's a page of images of the earth's magnetic field:


    All magnetic fields have this same shape, regardless of size.

    (I should qualify that by saying that on the sun [and stars in general] magnetic fields are extremely convoluted and complex and not static in form.)
  15. Dec 21, 2005 #14
    I understand what the shape of a magnetic field is, but let me try to ask it this way:

    Imagine a cylindrical magnet parallel to the Z axis in standard cylindrical coordniates. Assume I wanted to find the magnetic field intensity at some point R=1, Phi= doesnt matter, and Z = 0? So basically in the plane at its equator. How would I find this intensity and/or vector.

    Going from a standard representation of magnetic fields using a current-carrying coil, the vector would obviously be in the +- Z direction. Does the magnetic field intensity magnitude then fall off in the Z=0 plane, for a variable R, as R squared inverse? If so I can accept that, but what about everywhere else, say Z= greater than the magnet (above the North Pole), R=0. still 1/R^2 ?

    I'm trying to get discriptive formulae for B/H fields surrounding a bar or cylinder magnet.
  16. Oct 21, 2008 #15
    A reasonable proof is - a permanent magnet exhibits a static magnetic field. This magnetic field is termed a 'conservative force field'. This means that moving from one position A to another pos B in this field, the work/energy required is independant of the path chosen.
  17. Nov 3, 2008 #16


    User Avatar
    Science Advisor

  18. Nov 4, 2008 #17


    User Avatar

    Staff: Mentor

    Well they can get away with it because they aren't selling anything. They are always "almost" ready to start producing them.
  19. Nov 4, 2008 #18


    User Avatar
    Science Advisor

    Yes they obviously will never be able to supply some of those things that they're advertising (and it's so obvious that they don't even have them as the images shown are clearly rendered from a graphics program rather than actual photos). It's just such an obvious scam I wonder how they manage to avoid being shutdown by whatever fair-trade or other regulations they have in Germany where they seem to be based.

    I just poked around on their site and found some interesting things. Under the "technology" link there was this weak excuse.
    Then under the investor link there is this.
    So it looks like a pretty obvious scam. They're using the orders on the impossible free energy motors that clearly will never be delivered to give them credentials for asking for investor money that will no doubt go directly to allow Brady to continue to pay himself to run the company. What a disgusting scamster!
  20. Nov 4, 2008 #19
    I like how their company consists of one designer/inventor (cough crackpot cough) and an attorney :rofl:

    one to scam and the other to handle all the court cases.
  21. Nov 6, 2008 #20
    I like how old this (my) post is. Shows how far I've come in physics, I could completely answer my questions about magnetic fields of a cylinder off axis now. (expansion of poles for one).

    This is OLD! :)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Perendev Magnetic Motors Date
News SciFi Inspired Technologies Becoming Real; Turbolift Jun 27, 2017
Best place to buy the best cheap motors Apr 24, 2017
Who is this Jess Brewer? Aug 10, 2015
LittleBits - magnetic circuit board Dec 3, 2014