Author Topic: Using magnets instead of bearings? (Read 9647 times)

irethedo · « **on:** November 12, 2008, 11:12:59 AM »

Has anyone ever attempted to use magnets instead of bearings in a permanent magnet generator to support the rotator and to cut down on friction?

This seems like it could be a simple way to create a generator that spins freely and with little drag which might be ideal for a small wind turbine application or something that requires little force to turn it...

Any ideas on this or is there something out there already using this concept?

thanks

BEP · « **Reply #1 on:** November 12, 2008, 12:01:13 PM »

Lookup 'Halbach Array' and passive magnetic bearings.

They are used but rarely.

In my opinion if the motor can't overcome bearing losses easily then it likely won't work anyway.

Paul-R · « **Reply #2 on:** November 12, 2008, 02:08:12 PM »

Quote from: irethedo on November 12, 2008, 11:12:59 AM

Has anyone ever attempted to use magnets instead of bearings in a permanent magnet generator to support the rotator and to cut down on friction?

This is an off-the-peg item. Try googling for "magnetic bearing" or
http://www.waukbearing.com/
Paul.

nightlife · « **Reply #3 on:** November 12, 2008, 02:14:27 PM »

Here is a link I found.

http://www.grc.nasa.gov/WWW/spacemech/workshop02/mag-brg.html

yaz · « **Reply #4 on:** November 12, 2008, 11:22:37 PM »

Here's a pic of a Halbach Array bearing setup using square magnets. Seems easy enough.

capthook · « **Reply #5 on:** November 13, 2008, 12:29:02 AM »

nightlife is trying a magnetic bearing idea - see:

http://www.overunity.com/index.php?topic=6008.msg136731#msg136731

xingu · « **Reply #6 on:** November 19, 2008, 10:57:15 PM »

Yes, there is a solar rotation motor, which uses magnetic bearings in stead of ball bearings or whatever.
The rotating shaft just hangs in the air. The rotation occurs through solar cells and little coils.
It works fine, but sure isn't powerful enough to generate power through a generator.

xingu · « **Reply #7 on:** November 21, 2008, 12:24:30 PM »

Enclosed a picture, not of the best quality of the little device.
The solar cells look distorted, caused by the motion in the sunlight. The shaft is rotating.
Further it gives an excellent impression of the type of unusual magnetic bearings.
The rpm this little device handles in sunlight is app. 250.
At much higher rpm's I'm not sure the device will stay in one piece.

nightlife · « **Reply #8 on:** November 22, 2008, 12:02:43 AM »

xingu, the magnet bearing design that motor is using is not all that great and you can see where the shaft has been hitting the mirror and they should have used two sets of magnets on the ends with like polarities facing each other. There is also a much better way to use magnets for the up and down motion other then what they used. They should also have wrapped the ends and utilized all the magnetic movement to get more energy out of the design.

It does show that magnets can be used but there are better ways to use them.

xingu · « **Reply #9 on:** November 22, 2008, 04:37:14 AM »

Apparently the picture is not clear. The shaft is not hitting the mirror, the mirror is the only contact point the shaft has.
The shaft is held in midair through the two (four) underneath round magnets in front of the mirror and the ones at the other end of woodplate.
Positioning is essential for the round magnet on the shaft to hold it in its contact position with the mirror.
Otherwise the shaft would be flying off in whatever direction (forward or backward). Now the forward direction is choosen so it makes contact with the mirror.
Further there is no up and down movement, left out some imbalance in the components on the shaft.
What it does is, under light the solar cells with the coils and the underneath placed rectangular magnet, making the shaft rotate.
It is selfstarting.
The original question was about a magnet bearing doing its job with the least possible friction.
I think this is a good example of how this could be done. Nothing more nothing less.
Of course improvements can be made, depending on the use it is meant for, therefore I mentioned the rpm's.

nightlife · « **Reply #10 on:** November 22, 2008, 07:46:35 AM »

xingu,

Quote

The shaft is not hitting the mirror, the mirror is the only contact point the shaft has.

So which is it, does it touch the mirror or not? A contact point is the point where two or more touch and if they touch, it could be said that they are hitting each other.

xingu · « **Reply #11 on:** November 22, 2008, 10:59:45 AM »

OK I see what you mean now.
It seems my english fails me here.
In that case you could say 'is hitting' the mirror.
Sorry, my mistake.
Anyhow I hope 'the picture' of this magnetic bearing is clear now.

nightlife · « **Reply #12 on:** November 22, 2008, 02:56:04 PM »

xingu, thank you for clearing that up.

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Author Topic: Using magnets instead of bearings? (Read 9647 times)

irethedo

Using magnets instead of bearings?

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