Motors and Generators

It can't be that simple?!

Move a piece of wire next to a magnet and electricity is produced!


An Electricity generator

Yep, that's about all there is to making an electrical generator... whenever you move a conductor such as wire through a magnetic field, a voltage is induced at its ends. In fact an airplane flying through the magnetic field of the Earth has a voltage (or a potential difference) generated across its wings by the same principle.

Back to our wire would soon get tired of waving the wire about. Why not let the wind or water do the work for you?

If you wind up the wire into a circle to make a coil you could then balance it on some metal legs and let the wind move the coil for you. You have made a wind turbine to generate electricity! If you let water fall and spin the coil you have discovered hydro electricity.

Read about the New Zealand Energy Conservation and Renewable Energy Generation Pilot Project that Michael is involved with...


Lets sum up what we have done:


Move a wire next to a magnet ====> electricity comes out

METER.GIF (9534 bytes)

Motor from a tape recorder attached to an old power meter.

If the motor is turned by hand, the meter needle jumps  into the red showing that electricity is being produced. This unit can be converted into a hydro turbine or wind turbine and recharge a NiCad battery or lead acid battery.

Unit built by Vaughan Hale 1999

VIDEO CLIP: generator.wmv file


What if we reverse the idea of how a generator works?

electricity goes in ====> wire moves when next to a magnet

We have just invented a simple motor!


Try building the models shown and find out the answers to these questions:

  1. Who was Michael Faraday? What was his relationship with Sir Humphry Davy?
  2. What happens to the direction the coil spins when you connect the battery the other way around?
  3. What effect does changing the coil have? Try changing the number of turns of wire, the diameter of the coil, and the thickness of the wire.
  4. Build sensors to detect the current and voltage using a digital multimeter
  5. How is your generator similar to the turbines used at a hydro power station?
  6. How are other generators made differently?
  7. How are other electric motors made differently? Try this special musical motor...
  8. What is electromagnetic induction?
  9. Read about the New Zealand Energy Conservation and Renewable Energy Generation Pilot Project
  10. There are other ways to generate electricity. FInd out how to tap into fruits and vegetables here...
  11. Use an salt dough cell to power your own toys and cyberpets
  12. Some electrochemical cells can be used again and recharged. Try to make your own rechargable battery...


Selected by the sciLINKS program, a service of National Science Teachers Association.



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