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Code Number: 5K40.49b
Demo Title: Space Circles - Space Balls
Condition: Excellent
Principle: Motors, Electricity and Magnetism
Area of Study: Perpetual Motion
Equipment:
Space Circles Demo, Space Balls Demo, Fresh 9-volt Batteries.
Procedure:
See also 5K40.49b in Electricity and Magnetism
These demos are specially designed brushless DC electric motors. The moving parts have magnets in them and correspond to the rotor and flywheel of the motor. The base of the demo contains a battery, coil, steel core, and a transistor. The moving rotor induces an electric current in the coil. This current is amplified and fed into an electromagnet which applies a torque to the magnetic rotor.
References:
- H. Richard Crane, "A Spinning Top, Lenz's Law and Electric Watches", TPT, Vol. 22, # 2, Feb. 1984, p. 113.
- C.L. Stong, "An Electrometer, a Temperature Control Apparatus, and a Simple Electric Motor", The Amateur Scientist, October, 1965.