The same way electrical generators create electricity through chemical reactions, hydrostatic forces, wind and other forms of energy to power cities, magnetic generators can create magnetic forces as well as supplying electricity. You can even create a magnetic generator or a magnetic dynamo with supplies you can buy from the store or may have lying around your house.
Homemade Dynamo Generator Frame Setup
You can make a DIY generator, or dynamo, through some simple items you may have lying around your house. To make one, you'll need thick semi-thick cardboard, four small ceramic magnets, a hot glue gun, about 200 feet of magnetic wire, a small light bulb and a large nail. The generator works best with these materials so try not to substitute them. This homemade dynamo generator should be strong enough to light up a few small lightbulbs.
The first thing you'll need is a cardboard frame in the shape of a rectangular prism with no top or bottom faces. A good size is to make the top and bottom empty spaces about 8 cm x 3 cm with the faces facing left and right 8 cm x 8 cm and the faces facing forward and backward 8 cm x 3 cm. Other sizes may be more beneficial depending on the size of the magnets you'll use.
Instead of cutting out the faces of the cardboard and then taping them together, it can be more effective to cut out a long strip of cardboard with the width of the frame and the length as the sum of the lengths in one direction such that you can fold it in to the shape of the frame. This means cutting out a length of
with a width of 8 cm, folding it and taping it secure. Make sure the frame doesn't wobble or bend too much.
With the largest face of the frame facing you, create a small hole in the middle of it and a small hole in the middle of the face opposite of it. This is the hole you will place the nail through that can detect the magnetic current. Make sure the hole is small enough to secure the nail but large enough that the nail can spin freely in response to the magnetic field. See if you can spin it yourself without damaging the frame.
DIY Generator Magnetic Field Wiring
Remove the nail from the frame and tape the end of the wire to the box. Beginn wrapping the wire around the box. You'll need hundreds of coils around the frame to create a significant magnetic field that you can measure. You may consider placing the magnets in the frame as you wrap it to make the frame strong and secure enough to withstand the force of winding the wire around it.
Place the nail back into the two holes and secure two magnets inside the frame to both sides of the nail. Use hot glue to make sure they stay as opposed to tape or another material that may not conduct an electric current. Connect the ends of the wire to the two ends of the light bulb and spin your nail to see if it lights up. If you can, try spinning the magnetic nail to rotate it as quickly as possible.
Homemade Dynamo Generator Testing
This hobby dynamo or DIY generator should work by converting the magnetic field that the motion of the nail induces in the current to power the light. The magnetic field should induce a voltage into the windings of the wires. You can create a different kind of homemade dynamo generator using other methods such as varying the number of windings of the coil, using different sizes of the coil and using different magnetic coil materials.
Higher voltage lightbulbs may work more effectively as they can light up with smaller amounts of current. LED lights may work even better because they also can light up with small amounts of current. More powerful generators can be used to power entire circuits of light bulbs.
DIY Generator Converting Energy
This DIY generator is an example of an AC (alternating current) generator. The current at the ends of the two wires that plug into the light bulb alternates between the forward and reverse directions every time you spin the magnet. With every rotation of the magnet, the current undergoes a forward half cycle and a reverse half cycle, and the current alternates between them using a sine wave shape. AC current is found in most household appliances.
This type of hobby dynamo shows how magnetic generators convert mechanical energy into electromagnetic energy.When you use a galvanometer, an instrument to measure electric current, to measure the amount of current passing through a generator or wire, you can see the instrument's needle deflected. You can measure this change in magnetic field from the dynamo to test how strong it is. Scientists and engineers continue to study the potential of magnetic motors to improve engine efficiency.
In industrial settings, commercial electric generators wrap coils of wire tightly around circular arrangements of magnets. The magnetic field of the coil induces an electromagnetic force in the magnets. Hydroelectric power plants convert mechanical energy through a water turbine by the force of falling water. This generator conversion of mechanical to electrical energy contrasts that of motors, which convert electrical energy to mechanical energy.
Magnet Dynamo Physics
You can calculate the electromotive force (emf) produced by the number of coils in your generator using the equation V = NBAω sin ωt for emf voltage V, number of coils N, magnetic field B, area over which the coils are arranged A, angular frequency ω ("omega") and over time t. The angular frequency measures the frequency, the number of waves of electricity which pass over a single location in a second, multiplied by 2π.
You can treat a magnet dynamo as though it were an electric generator because electricity and magnetism are both part of the same force. Changes in an electric field create a magnetic field while changes in a magnetic field create an electric field. While this DIY generator shows how a magnetic field can create an electric current, other observations can show you how electricity can cause magnetic phenomena as part of the same electromagnetic force.
If you placed a magnetic compass near a wire in an electrical circuit, you would notice deflection of the compass needle. This happens because the current through the wires in the circuit create magnetic fields that cause the compass needle to change direction. Compasses are built to respond to changes in the Earth's magnetic field so the presence of an external magnetic field would also cause this deflection.
This fundamental connection between electricity and magnetism also means you can create your own electric generator in the same way as the magnetic one. Spinning a magnetic object around a coil of wires would generate an electric field as well as a magnetic one. Other creative ideas may take using more powerful sources of mechanical energy such as bicycle machines or windmills to generate electricity the same way.
- Instructables: How to Make a Magnet Generator
- The Creative Science Center: Making an Electrical Generator
- Hyperphysics: How Does an Electric Generator Work?
- Northwestern University: Electricity & Magnetism
- Lumen: Electric Generators
- US Energy Information and Administration: How Electricity is Generated
- Top Magnetic Generator: How Generator Works
- Engineering.com: Magnetic Motor Aims to Revolutionize Engine Efficiency
- Children should be supervised by an adult when using the knife.
- Never connect the wires to an electrical outlet.
About the Author
S. Hussain Ather is a Master's student in Science Communications the University of California, Santa Cruz. After studying physics and philosophy as an undergraduate at Indiana University-Bloomington, he worked as a scientist at the National Institutes of Health for two years. He primarily performs research in and write about neuroscience and philosophy, however, his interests span ethics, policy, and other areas relevant to science.