How to Build an Electric Motor

by Isaiah David

Although it is not widely used today, the homo-polar motor has an incredible elegance and simplicity to it,. making it an ideal electric motor for a first home project. It is the simplest kind of electric motor you can build and can be put together in just a few minutes at very little cost. Make one before you try more difficult and sophisticated styles of electric motor.

Put a neodymium magnet on the head of an iron nail. The magnet should be small and disk-shaped, and the nail should be free of any corrosion or coating.

Allow the magnetic force to attach the nail to the battery. Hold the nail so that the tip is facing up and hold one terminal of a cell battery (AA, C, and D batteries work well) against it. The nail should dangle from the battery.

Take a small piece of copper wire and tape it to the other terminal of the battery. You can either use bare wire or you can strip off a bit of enamel from each end to get a clean connection. Make sure the copper is in contact with the battery.

Put on some safety glasses. Once this motor gets going, it can spin at up to 10,000 rpm, so you want to be prepared if it flies off in the middle of things.

Touch the side of the magnet with the free end of the wire. It should start spinning immediately.

Control the speed of the electric motor by touching and removing the end of the wire in contact with the magnet. It takes a while to climb up to full speed, so you can easily keep it going at a more reasonable rate.

Tips

  • check You can slow down the motor by disrupting the flow of current. Put a coin between the wire and the terminal on top of the battery.
  • check Try using two batteries stacked on top of each other to get a faster motor.
  • check Try out different sizes of magnets. See if they make the motor faster or slower.

Warning

  • close This project is not very dangerous, but there is a risk of flying magnets and nails. Supervise any kids trying it.

Items you will need

About the Author

Isaiah David is a freelance writer and musician living in Portland, Ore. He has over five years experience as a professional writer and has been published on various online outlets. He holds a degree in creative writing from the University of Michigan.