The World's Simplest Electric Motor
Four simple objects make a small motor
Online since: 11/11/2007, Number of visits: 1156860
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An experiment was reported in the magazine Physik in unserer Zeit that totally amazed everyone at supermagnete.dk. Just when we were coming to terms with our fascination for our own magnets we learned that, with one of our magnets and only 3 additional elements, it would be possible to build a small electric motor... virtually unbelievable. A mere 5 minutes later we had re-created the motor and could not stop ourselves from spinning the magnets. An incredible phenomenon!
- 1 iron screw
- 1 alkali battery
- 1 piece bared copper cord
- 1 disc magnet of your choice (detailed information below)
- Connect the head of the screw with the disc magnet
- Connect the tip of the screw with the negative pole (lower side) of the battery.
- With the index finger, press the one bared side of the cord onto the positive pole (see photo below).
- Grab the cord with the other hand and touch the magnet with the free end of the cord on the outer side
Suitable MagnetsWe were able to achieve the above mentioned results with nearly all of our neodymium disc magnets. It worked best when we used a disc magnet with a diameter of at least 8 mm and a height of at least 3 mm. It definitely is more fun to do this experiment with larger magnets.
If you already own a neodymium disc magnet, give it a try. There's a good chance that you will be able to get the magnet rotating with the described apparatus.
For Advanced UsersEndless variations are possible. Here again, a sphere K-19-C is brought into rotation. This is accomplished with a double tetrahedron made of connected rod magnets and steel spheres that rotates at an amazing speed.
Tips and Tricks
- You can't get the magnet to rotate? The most important thing, naturally, is that the circuit is closed. Make sure that the tip of the screw is in direct contact with the underside of the battery. During your first attempts, use larger magnets - success is usually easier to achieve with these.
- The screw wobbles? You have probably used a screw with a crooked tip. File the tip until it is straight or try another screw.
- My rotating sculpture is too heavy; the magnetic pull is not strong enough to hold onto the battery. Connect the battery and screw with a small sphere magnet, for example the K-08-C (shown in the last photo above).
- Tip for the lesson [from our customer Michael Sexauer]: "It's particularly impressive, and also visible to those students sitting in the back row, when a paper pinwheel is attached to the magnets. You get an instant fan!"
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