open-source-energy.org

Open - Source - Research => Open-Source Research => Magnet Based Systems => Topic started by: Apoc4lypse on May 25th, 2018, 04:24 PM

Title: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Apoc4lypse on May 25th, 2018, 04:24 PM
ok well I've had a few different ideas for how to get magnets to spin a rotor over the past years, some are stupid and just don't work, some I've tested, some I haven't...

This ones different and I don't think I've really seen this version anywhere so I'm going to post the femm files for it since I don't know if I'll ever get a chance build and test it being that the Mu-Metal shields would need to be a kind of custom order placed somewhere since Mu-Metal cannot be shaped once it is specially heat treated for permeability.

Now I know we can't shield a magnet from another magnet, but we can shield a non magnetized magnetic material from another magnet using high permeability materials such as Mu-Metal.

I used a lua script I found on the overunity forums to run a torque analysis on the system rotating the rotor and the "stator magnets" in opposite directions at 1 degree increments. It gets positive torque and some negatives, but the average ends up being positive. The design probably needs to be reworked further before being built however to get it to really work right plus the Mu-Metal shielding needs to be a certain thickness and have a magnetic permeability curve that correctly absorbs the magnetic fields on one side of the stator magnets while allowing some field to escape on the non mu-metal shielded side that interacts with the rotor.

The idea uses magnets to interact with a ferromagnetic or in this case cast iron rotor that is designed as a spiral. The magnets attract to the spiral making the rotor spin the outer most part of the spiral closer to the magnets while the magnets rotate in the opposite direction via a gear system connecting the rotor to the "Stator Magnets" which rotate on the outside of the rotor. The magnets have one half side of them "shielded" with Mu-Metal to absorb the magnetic flux on one side of the "stator magnets". The gears would be set so that the magnets rotate at the same RPM as the rotor so that that the Mu-Metal blocks the magnets from sticking to the outer most part of the spiral to continue the magnetically induced rotation on the rotor and help minimize the sticking point.

Idealy a uniform radial ring (or radial disc?) magnet would probably work the best verse the diametrically magnetized magnets I used in the simulation, but femm can't really simulate this type of magnet, and a simulation needs to be run in order to figure out the correct size and permeability needed for the Mu-Metal shields on the stator magnets.


Things that need to be considered are the negative torques that the stator magnets would add back into the rotor also however I think this can be again overcome using gears.

Different sizes designs and materials for the rotor need to be tested still or simulated, along with different sized magnets with different sized Mu-Metal Shields, with the magnets used in this setup it seems like a mu metal shield that is half the diameter in thickness of the magnet itself seems to work the best. The trick is to absorb as much as possible on 1 half side of the magnet while still letting magnetic field escape out the other side of the magnet and interact with the rotor when the magnets are not shielded from the rotor at the "sticking points" as people have come to call those locations in most magnet motor designs.


I hope this can be of help somehow, the Femm files from my most successful simulations with the best torques I've gotten so far are attached along with a magnetic field image of mm5 the one that seemed to work the best, the torque isn't amazing but I still think its something that can be worked with and the design refined for better outputs.

Other thoughts I had were ideas involving similar methods and using a "Murray" Rotor design to possibly get better results but I do not have a 3d magnetic simulation program to test any of those ideas with really.

I just wanted to get people thinking about using Mu-Metal and different magnetic permeability's to further this idea along. While we cannot shield a magnet from another magnet, we can still shield a non magnetized ferromagnetic material from a magnet and then unshield it under its own power to achieve a force.

The energy or power comes from the magnetic field being transferred from the magnet to the ferromagnetic rotor, I realize the rotor would eventually become magnetized over time from interacting with the magnets, so the rotor would eventually need to be replaced with a non magnetized one.

Let me know what you guys think.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Matt Watts on May 25th, 2018, 06:28 PM
Quote from Apoc4lypse on May 25th, 04:24 PM
While we cannot shield a magnet from another magnet, we can still shield a non magnetized ferromagnetic material from a magnet and then unshield it under its own power to achieve a force.

Let me know what you guys think.
The concept of shielding is a bit of a misnomer.  What you are actually doing is redirecting the magnetic flux.  Mu-Metal acts like a sponge to the flux and drags it away from where it would normally go.  Just keep in mind the flux is still present in the Mu-Metal and will still attempt to "close the loop" if it can.

There's been quite a few people attempt to design Mu-Metal "shielded" motors only to discover the Mu-Metal creates immense cogging due to it being so attractive to the magnetic fields present in the vicinity of permanent magnets.

Where Mu-Metal can be of great value is using it as a magnetic switch to alter the flux path from one core to another.  I haven't seen anyone specifically pursue this approach but feel it has merit.

Something else that should probably be looked at in greater detail is the work of Howard Johnson.  He found interesting arrangements of flux patterns near straight and curved edges that could be of benefit.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Apoc4lypse on May 25th, 2018, 10:34 PM
Yeah it takes up less text to say magnetic shielding. Should just call it magnetic absorption.

Has anyone had much success with howard Johnson's designs? I know I've seen videos of that sort of design but nothing working and stick points still being an issue.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: overunitydotcom on May 27th, 2018, 09:58 AM
What  forces does the simulation show ??
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Apoc4lypse on May 31st, 2018, 10:09 PM
It was showing a couple grams of torque on the central rotor, but I think this can be increased by playing with the design and magnets size and strength as well as the magnetic permeability of the metals involved and their sizes. Like matt said cogging is an issue though, but here the magnets aren't moving in respect to the mu-metal so they don't have to deal with getting stuck on the mu-metal and the main driver is the non magnetize ferromagnetic material being attracted to the magnets. The magnets have mu metal on one side so they can be shielded from being attracted to a degree to the rotor at the sticking points. Eventually however the non magnetize metals will become slightly magnetize then becoming attracted to the mumetal shields which would lead to more cogging.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Cycle on May 31st, 2018, 10:37 PM
Quote from Apoc4lypse on May 31st, 10:09 PM
It was showing a couple grams of torque on the central rotor, but I think this can be increased by playing with the design and magnets size and strength as well as the magnetic permeability of the metals involved and their sizes. Like matt said cogging is an issue though, but here the magnets aren't moving in respect to the mu-metal so they don't have to deal with getting stuck on the mu-metal and the main driver is the non magnetize ferromagnetic material being attracted to the magnets. The magnets have mu metal on one side so they can be shielded from being attracted to a degree to the rotor at the sticking points. Eventually however the non magnetize metals will become slightly magnetize then becoming attracted to the mumetal shields which would lead to more cogging.
Periodically degaussing would solve that quite handily, I bet.

Yes, you can degauss bulk metal... we used to degauss the entire submarine to remove any trace magnetic field caused by traveling for a long time in one direction (usually when on station, chugging along at 1 knot, monitoring adversary maneuvers near their ports). This makes the submarine stealthier.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: nav on June 1st, 2018, 09:08 AM
Quote from Cycle on May 31st, 10:37 PM
Periodically degaussing would solve that quite handily, I bet.

Yes, you can degauss bulk metal... we used to degauss the entire submarine to remove any trace magnetic field caused by traveling for a long time in one direction (usually when on station, chugging along at 1 knot, monitoring adversary maneuvers near their ports). This makes the submarine stealthier.
Whats the best way to degauss that is cheap as far as energy is concerned?
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Lynx on June 1st, 2018, 11:07 AM
Quote from nav on June 1st, 09:08 AM
Whats the best way to degauss that is cheap as far as energy is concerned?
I still use an old CRT monitor which has a degauss button, I guess it uses some form of AC applied on a coil which is wired around the back of the cathode ray tube itself.

(http://www.designworldonline.com/wp-content/uploads/2015/12/degausser.jpg)
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Cycle on June 1st, 2018, 05:11 PM
Yeah, it's just a coil of wire and an AC frequency to wipe out any stray magnetic remnant. Hit it for 5 seconds or so whenever it gets magnetized, and it should degauss it.
Title: Re: Possible Magnet Motor Design using Mu-Metal Shielding (femm files)
Post by: Apoc4lypse on June 4th, 2018, 10:41 AM
I was looking at degaussing too a bit when I was working on this. It depends on how much magnetic field you are trying to remove. Some degaussers they have are for demagnetizing big pieces of magnetized metals and they consume far more power than a simple CRT Degausser does because thats a small magnetic field within the monitor being removed.

Although I think the same concept could be applied to the rotor in this case because the magnetization process would be relatively slow for the maion rotor. (Think passing a piece of metal past a neodymium magnet) It gets magnetized the more times it happens, neo magnets will even slightly magnetize metals they are attached to for long periods of time but the magnetization they end up producing is usually pretty small, in a moving system like this it might be a bit bigger though. What I worry about is the eddy currents interacting with the newly formed magnetization on the rotor, making this effect greater.

Degaussing the rotor while its spinning is a great idea though, but I'm not sure what sort of deguasser and how much power would be required to eliminate the types of magnetic fields forming on it... from what I understand deguassing magnetized metals is different than simple deguassing of a CRT monitor, but I don't really understand how that all works.