The Steorn Permanent Magnet Motor Replication Project: It's FLUX time.

[thevorlon]

Has anyone here tried to replicate the LEMA itself yet and build a rotor to see if it's possible to use the LEMA by HAND (moving the shield back and fourth) to make the rotor rotate?

I think that is the first step. The second step would be going from that to having a device using some of the rotor's force to move the shield.

[cache]

Hey - where did everybody go? Have we got a group of guys that have dates on a Friday, or a group of guys that are all trying to get from the theoretical to the practical stage? 

thevorlon, I finally got some co-netic & netic shielding today from http://www.magnetic-shield.com/products/lab-kit.html . I built my first rough LEMA and "tried it by hand". Well, this puppy is going to probably run faster than 600rpm. With two magnets on the rotor that's 1200 LEMA shuttles per minute. Can't tell much when I'm only moving about 30 shuttles per minute. But here's what I did find.

Even if you completely surround the magnet with shielding at least 20% of the field still gets through. The documentation sent by magnetic-shield.com confirms that. This means that a design will need to use repulsion instead of attraction. Here's why....

With attraction the actuator magnet has to be exposed while the rotor magnet approaches because that is when all of the work gets done. But, since magnetic fields dissipate their strength rapidly over distance, 20% is probably all that is going to be available through out the 1/4 arc that the rotor magnet is moving. Once the two magnets are facing each other you then shield the actuator. At that point you still have 20% attraction bleeding through. All you've done is attract the rotor magnet with a small portion of the magnetic force, and you're stuck at that point.

With repulsion the actuator magnet is shielded while the rotor magnet approaches. 20% of the repulsive force is bleeding through to act as a break on the rotational torque. But, when the two magnets are facing each other you remove the shield and 100% of the repulsive force now is applied to the rotational torque as acceleration. As the rotor magnet moves past the actuator the shield is closed - once again 20% bleeds through, but this time the rotor is past dead center so this bleed through accelerates, cancelling the earlier breaking effect.

Also, I think that the sheild has to move ONLY when the two magnets are dead center to each other, not before or after. Take a look at a motor using an electromagnetic actuator. The reed switch closes the circuit that energizes the electromagnet. You can adjust how long the reed switch is closed (and how long the electromagnet is energized) by moving the reed switch closer or further away from the magnet that is closing it.  If you increase the length of time, you decrease the speed of the motor. Maximum speed is achieved with the shortest pulse, not the longest. But, if you lengthen the pulse, and also adjust the position of the reed switch so it closes exactly at dead center and remains closed until the rotor magnet has cleared the circumference of the actuator magnet then you can slightly increase speed.

This observation is why I prefer using something like a reed switch to activate the shield shuttle on a LEMA. I don't see how yopu can get that kind of timing using gears or cams. I totally agree with your point that having an external power source involved just totally messes things up for demonstration purposes. But, I have a couple of ideas for doing that with power from the device itself. The device's rotating shaft is a good place to mount a second set of magnets within a coil producing a dynamo-type electric current.

"The most exciting phrase to hear in science, the one that hearlds the most discoveries, is not 'Eureka!' (I found it!) but 'That's funny,,,' " ISSAC ASIMOV (1920-1992)

[thevorlon]

Cache,

Let me see if I understand this, because I would love to try and build one of these LEMA's.

We will have magnet A and magnet B in this example. Both of of these are the magnets of the LEMA. The X will represent the rotor magnet.

Lets say the magnet sweeps in and passes what would be the sticky point of magnet B moving clockwise..

          X
        ___

   A     B

Obviously, you would want to move the shield out of the way quickly so that magnet B can give the rotor magnet "X" a push. The shield moves over magnet "A".

          X
___

  A      B

Then it's obvious the rotor magnet would move forward.

     X
___

A       B

My question to you is if you believe you could then move the shield BACK over magnet "B" fast enough to give the rotor magnet "X" an additional "push" of energy from magnet "A".

X
       ___
   
A      B

Basically, I'm trying to figure out what movement of the shield of the LEMA is most efficent at producing the most repulsive energy and of course what is actually possible. Would it indeed be possible to move the shield back and fourth that fast?

Now, one other question.

You gave the figure 20% for the leakage of flux from the magnet. My question to you is about another figure. The design of the LEMA is supposed to allow the shield to move easily with low energy. What percentage of energy do you think moving the shielding of the LEMA takes compared to a typical conventional motion of moving a piece  of shielding away from the same magnet?

In my opinion, that has to be the key to the LEMA. Because otherwise anyone could have created a system to simply move a shield back and fourth infront of a magnet. The principle of the LEMA must be that it's VERY efficent at moving the shield.

Could you say how much enegy is saved in the LEMA setup?

By the way, thanks for the information and update!

Do they sell small samples of the shielding material for the general public (enough to build one or two LEMAs?

[gyulasun]

Hi,

I have just seen a reference to a Russian magnet motor here on the Forum
( http://www.overunity.com/index.php/topic,1621.msg16034.html#msg16034 )

and seeing the picture animation (I attached it below) it immediatly cries for perhaps the simplest and still a good mechanical solution to combine it with the LEMA.
I would replace the top magnet in the picture with the three magnets of the LEMA in an appropiate way and everything else can remain the same! 
For more shaft torque you can place several such arrangements next to each other on the same shaft.
I don't think any exotic shielding material would be needed: just the good old transformer laminations can be used, experimenting / testing for the correct thickness. Another material of interest is ferrit, but it is probably more expensive than lamination.  The mass of the rotor can also be of significance of course.

Regards
Gyula

   

[Kent767]

..... I don't see how yopu can get that kind of timing using gears or cams.

Nonsense... Cams drive the timing of the internal parts of the motor on your CAR!

which run at RPMs up to  the 5000+ rpm range.