How to Build a Permanent Magnet Motor

Michael Faraday invented the principle of the electric motor in 1821. Several inventors tried turning this theory into a practical working model in the years afterward. However, the first truly practical electric motor was not invented until 1871 by Zenobe Theophile Gramme (See Reference 1). An electric motor is, in essence, a coil of wire on a rotating armature. The armature sits close to one or more magnets, so that it experiences a powerful magnetic field. When electric current is run through the coil it generates a magnetic field of its own which interacts with the field of the magnets, turning it. (See Reference 2)

Things You'll Need

• 2 large paper clips
• 1 paper, styrofoam, or plastic cup
• 1 to 3 disc magnets smaller than the bottom of the cup
• D battery
• 2 6 inch wires
• 3 feet of solid 22 gauge wire
• 2 alligator clips
• Roll of electrical tape
• Permanent marker
• Rubber Band

Instructions

1. Wind the wire around the battery so that it forms a coil. Leave three or four inches of wire trailing out of the coil on each end. Straighten these so that they stick straight out from the sides. Tape the coil so that it does not unravel or come loose. Cut approximately one inch of insulation off of the ends of the coil's wire using the wire strippers (See References 3 & 4). Darken the top of one of the ends of wire with the permanent marker. Leave the bottom of that end unmarked. This will help keep the motor from getting hung up when the coil lines up with the magnetic field of the motor. (See References 3)

2. Straighten out the paper clips, leaving a hook of bent metal on one end of each. Turn the cup upside down and affix the paper clips to the cup's bottom with the rubber band. The paper clips should now be sticking straight up from the bottom of the cup, holding their hooked ends above the upended cup (See References 3 & 4).

3. Place the magnet on the bottom of the cup, between the paper clip hooks. If you are using more than one magnet then stack them up. Using multiple magnets will increase the strength of the magnetic field that the coil is exposed to. This will result in a more powerful motor. (See References 3 & 4)

4. Place the straight ends of the coil of wire on the paperclip hooks. Make sure the hooks are touching the bare metal on the coil. Turn the coil all the way around, making sure that it clears the magnet as it turns. If it does not, adjust the position of the paperclip hooks by sliding them up under the rubber band. Keep the coil as close to the magnet as possible (See References 3 & 4).

5. Remove approximately one inch of insulation from the ends of the short wires with the wire strippers. Affix each wire to one of the alligator clips. Clamp these alligator clips onto the paperclip hooks. This creates a path for the electricity to reach the coil. Connect the other ends to the positive and negative terminals of the battery, using the electrical tape (See References 3 & 4).

References

• MAGCRAFT: History of Magnetism and Electricity
• Georgia State University Hyperphysics: AC Generator
• University of Wisconsin-Madison: Build an Electric Motor
• PBS Rough Science: Build an Electric Motor

Resources

• National High Magnetic Field Laboratory: Magnets from Mini to Mighty