Floating object in magnetic field

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Thread Starter

Thyristor

Hello. I am trying to make a 1,5 kg steel ball levitate in a megnetic field (!). The high currents should be regulated by Siemens SIMOREG DC drives. Has anyone ever done this before? What happens with SIMOREG if the load is not a DC motor, but a big electromagnet (coil)? Has anyone information about floating objects in magnetic fields?

Thanks a lot!

Hannes
 
M
Sounds like fun, exactly why do you want to float 1.5Kg weight?

I would think that the as long as you don't exceed the max load current rating of the drives, there should not be a problem, current is current.
For sure though, put in a seperate overcurrent protection device to disconnect the supply side if things get out of hand.

Basic theory, the current will determine the field strength, the field strength would be the determining factor of how high you can lift the object relative to its weight. or if the field comes up too quickly, you might have a 1.5Kg projectile to deal with, so ramp time to the required current level and the magnet properties will determine how much current is absorbed. too much and you over heat things and saturate the core, too little, no effect. also sounds like you have some reading to do before you lift this thing off the ground (so to say). start small, understand the theory first, I would not recommend attempting to lift any appreciable weight without going through the basic calculatins, doing the theory and making a small working model. Also checkout white papers writing by people from Sandi Labs, General Dynamics, General Atomics and other such companies, I am sure thay have all played around with this idea to some degree.

If you make it work, we all want to see the results and of course a suitable white paper and your picture in Scientific American!!

matt
 
C

Curt Wuollet

That is rather interesting!

Intuitively, the transfer curve of I/distance will be "brittle" due to the square law of attraction and distance and most other parameters, requiring high gain and wide swings of current before stabilization. A large mass may actually be easier than a small mass as the speed needed to keep up would be less. I would be interested in how you intend to sense position for feedback and of course, how close my intuition is. Best of luck, I wish I had time for stuff like this. They levitate whole trains in Japan.

Regards

cww
 
Floating objects in a magnetic field requires a very very strong electromagnet. I ever tried once during my college days. You can float non ferrous sheet metals like aluminum, copper in between the fields.

Actually when you try to move the plate you induce a voltage inside the plate which produces a large ciculating current and thereby a force preventing you from pulling you. I remember we used around 2000 amperes in to the coil at about 20 volts (not sure of turns now) through a big stack of selenium rectifiers.

Regards
Sekar
 
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