How to Make Electromagnetic Electricity

Electromagnetic electricity is created by the movement of a conducting wire through a magnetic field. The motion causes a difference in electric potential across the wire, which allows a current to flow when there is a circuit attached to it.

The size of the current generated will depend on the speed of movement, the size of the magnetic field, the number of times the wire is looped, the size of each loop, whether the wire is looped around a magnetically permeable core and the material the wire is made from.

Things You'll Need

• 3-by-14-inch strip of corrugated cardboard
• 2-inch bar magnets, two
• 6-inch iron rod of less than 1/2-inch diameter
• 1 foot of insulated copper wire
• Double-sided sticky tape
• Strip of thin card
• Strip of aluminum

Instructions

1. Fold the cardboard strip into a rectangular box with the longest sides about 5 inches long. Affix the bar magnets along the longest sides so the opposite poles are facing each other. Pierce the cardboard through the middle of the shorter sides of the box and widen so the iron rod can turn freely inside them.

2. Slide the iron rod into the box. Wrap the copper wire around the middle third of the rod, leaving enough wire free at the start and end to be able to reach one of the ends of the rod. These ends of the wire will form the electrical circuit, so it is essential that they reach the same end.

3. Wrap a piece of double-sided sticky tape around the end of the rod where the copper wires are. Cover the tape with the thin card, to form an insulating barrier. Strip the insulating wire from the last half-inch of the wires and fasten them to the card using double-sided sticky tape.

4. 

   Aluminum contacts between generator and circuit conduct electricity well.

   To generate DC electricity, cut the aluminum strip in half, then trim each edge to reduce its size. Affix the trimmed pieces to the rod so each covers one of the wires, but the strips do not touch. This creates a split ring, which ensures the polarity of the electric circuit cannot switch. To generate AC electricity, simply wrap the aluminum strip around the exposed wires.

5. Spin the rod. The movement of the coil in the magnetic field will generate an electric potential. When attached to a circuit, this electric potential will be enough to make electromagnetic electricity flow. On a small scale, this can be used to light a small light bulb, as in the dynamo on a bicycle. In large industrial systems, a generator of this sort can power any electrical device.

Tips & Warnings

• Because electromagnetic electricity is only generated when the conductive material is moving through the magnetic field, the rod must be turning constantly in order to generate a constant flow of electricity. This is made easier if the rod is attached to a handle, to make it easier to turn, or motor of some description, which will keep the rod moving.

• Generating a large voltage can be dangerous, or even fatal. When working on an electric circuit, always ensure it is first disconnected from its power source. Ensure the rod is no longer turning in the generator before altering any part of it, and if using a motor to turn the rod, be sure it is both disconnected and switched off.

References

• James E. Koehler: Electromagnetism and Generators