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Author Topic: Hi amp bearing motor  (Read 11074 times)

tinman

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Hi amp bearing motor
« on: January 12, 2014, 04:51:59 AM »
Most of us would have seen one befor,but how many know how it work's?. Some say the balls heat up on one side and deform the ball so as to create rotation-a push from the ball ,due to an oval shapeforming from heat on the ball's. Who knows why this isnt what is happening?,nor how it works.

http://www.youtube.com/watch?v=g60okBMeTKo

Would it work with AC,as well as DC?. One would have to say it would,as it rotates in both directions with DC-regardless of polarity.

Testing comeing soon.

And is it related to the workings of the homopolar motor?
http://www.youtube.com/watch?v=hXbFfMBW97A

broli

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Re: Hi amp bearing motor
« Reply #1 on: January 12, 2014, 09:11:30 AM »
Yes it will work with AC and the "rotation due to expansion" is just a theory. Noone, as far as I know, replaced the bearings with discs and carbon brushes to show that it's not due the expansion/contraction of the ball bearings, my guess is that it even will work with brushes.

TinselKoala

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Re: Hi amp bearing motor
« Reply #2 on: January 12, 2014, 07:26:16 PM »
I'm another one who can't quite buy the "thermal expansion" theory of why this motor operates. I don't have an alternative explanation, though.
I don't think it's a homopolar motor and I don't think that a disc-brush version would work, without making it a homopolar system by including a source of magnetic field in the right orientation. These are empirical questions though. (A true homopolar motor will "selfstart" but this system needs a nudge in either direction to start spinning.)

The problem with experimenting with this system is that it requires high currents, several tens or even hundreds of amperes, to operate, and whether AC or DC, these kinds of current levels can be dangerous and may be more than the table-top experimenter is able to handle easily and safely. The typical power source for this experiment, a car battery, can actually explode if any of several possible adverse events occur during this experiment.

tinman

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Re: Hi amp bearing motor
« Reply #3 on: January 12, 2014, 09:20:15 PM »
I'm another one who can't quite buy the "thermal expansion" theory of why this motor operates. I don't have an alternative explanation, though.


This alone is reason it should be looked at some more-a challenge.
Maybe Poynt or MH would like to have a go at it?. But first we need a safe power supply that wont explode,and i think i have just such a supply.

I believe it dose work via produced magnetic field's-some how???.

broli

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Re: Hi amp bearing motor
« Reply #4 on: January 12, 2014, 09:44:05 PM »
I'm another one who can't quite buy the "thermal expansion" theory of why this motor operates. I don't have an alternative explanation, though.
I don't think it's a homopolar motor and I don't think that a disc-brush version would work, without making it a homopolar system by including a source of magnetic field in the right orientation. These are empirical questions though. (A true homopolar motor will "selfstart" but this system needs a nudge in either direction to start spinning.)

The problem with experimenting with this system is that it requires high currents, several tens or even hundreds of amperes, to operate, and whether AC or DC, these kinds of current levels can be dangerous and may be more than the table-top experimenter is able to handle easily and safely. The typical power source for this experiment, a car battery, can actually explode if any of several possible adverse events occur during this experiment.

There is a paper out there that pretty much explains it and asks other interesting questions:

http://arxiv.org/ftp/physics/papers/0012/0012009.pdf

The fact you need to give it a nudge makes sense as well, you need a small circular component to create your "magnet". However in the paper the circular component is there by design thus the starting torque is not 0.

tinman

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Re: Hi amp bearing motor
« Reply #5 on: January 14, 2014, 02:33:46 PM »
Good paper broli-cheers.

So who here would like to have a go at showing what the magnetic fields may look like,in the pic below?-that is if there is any magnetic fields. One would think there would be,as we have two single wound coils,with high amp's passing through them on each bearing-being the inner and outer rings of the bearing.

Low-Q

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Re: Hi amp bearing motor
« Reply #6 on: November 19, 2014, 05:38:46 PM »
You can easily exceed 500 A with this battery. If you clearly see that the wires want to separate, the current flow is so great that the magnetic field along one single wire are pushing or attracting the other wire out of initial position by several millimeters.


I have seen similar behaviour in spot welding equipment where two parallell wires 50mm in diameter separating with great force.



Vidar

Low-Q

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Re: Hi amp bearing motor
« Reply #7 on: November 19, 2014, 05:45:44 PM »
Good paper broli-cheers.

So who here would like to have a go at showing what the magnetic fields may look like,in the pic below?-that is if there is any magnetic fields. One would think there would be,as we have two single wound coils,with high amp's passing through them on each bearing-being the inner and outer rings of the bearing.
I don't think magnetism is the reason why these bearings start to rotate. It must be due to heat expansion. There is no defined direction where the balls are moving if magnetism would be the reason - not even if the rotor have an initial spin.


When the balls heat up they expand, and want to escape the narrow space they have got as they cool down. If you're not spinning it in advance, the bearing will not start the rotation because the balls on each side is equaly heated.
However, if you spin it first, the delay in heating will cause the balls to be most expanded after the point where the wires are attached, and therfor it will continue to spin when current is applied. My 5 cents.


Vidar