How to Make an Electric Motor

Sarah Boaz

• One "D" cell alkaline battery
• one wide rubber band
• two large paper clips
• one rectangular ceramic magnet
• heave gauge magnet wire (the kind with red enamel insulation, not plastic coated)
• one toilet paper tube
• fine sandpaper
• OPTIONAL: glue, small blocj of wood for base

1. Starting about 3 inches from the end of the wire, wrap it 7 times around the toilet paper tube. Remove the tube (you don't need it anymore). Cut the wire, leaving a 3-inch tail opposite the original starting point. Wrap the two tails around the coil so that the coil is held together and the two tails extend perpendicular to the coil.
   NOTE: be sure to center the two tails on either side of the coil. Balance is important. You might need to put a drop of glue where the tail meets the coil to prevent slipping.
2. On one tail, use fine sandpaper to completely remove the insulation from the wire. Leave about 1/4" of insulation on the end and where the wire meets to coil. On the other tail, lay the coil down flat and lightly sand off the insulation from the top half of the wire only. Again, leave 1/4" of full insulation on the end and where the wire meets the coil.
3. Bend the two paper clips (needle-nose pliers may be useful)
4. Use the rubber band to hold the loop ends to the terminals of the "D" cell battery
5. Stick the ceramic magnet on the side of the battery
6. Place the coil in the cradle fromed by the right ends of the paper clips. You may have to give it a gentle push to get it started, but it should begin to spin rapidly. If it doesn't spin, check to make sure that all of the insulation has been removed from the wire ends. If it spins erratically, make sure that the tails on the coil are centered on the sides of the coil. Note that the motor is "in phase" only when it is held horizontally.
7. For display, you will probably need to build a small cradle to hold the motor in the proper position. It might also help to bend the ends of the coil a bit so that as it slips right or left, the bends keep it in the proper position

• Try making different shaped coils and see how they work
• Try varying the number of wires in the coil
• Turn the coil slowly by hand and feel the magnetic attraction at each point of the coil

• How long can you get the motor to run before it falls off the cradle?
• How can you determine the speed of the motor (in RPM-revolutions per minute)?
• Can you make this motor do any work for you?

How your motor actually works | More information on materials | Troubleshooting