A Rogowski coil, like most things in science, is named for the inventor or the person who made the discovery. In an industrial setting, it plays a major part in measuring alternating current and detecting spikes in current flow. It is built on a much larger scale there, but you can build a smaller model in your high school science lab. With the spring science fair occurring in most schools now, you probably want to give the kids some ideas by first showing them how to construct this seemingly simple device. Here is how to do just that.
What You Will Need
To build a Rogowski coil, you will need:
- Copper wire, or some other metal wire that conducts electricity really well
- An electrical lead, about six to eight inches long, depending on the intended diameter of your coil
- A conductor in the form of a pole or cylinder
- An integrator circuit, preferably one mounted to a board so that the kids can see how this instrument operates
- A battery or some other type of device that will produce a little bit of electricity for the coil
Once you have collected all of these items, place them on the lab table in front of you before the start of class. Then explain what this device is, and how it is typically used in factories and electrical plants. Then you can begin to build the coil.
Building the Coil
- Take a pencil and wind the copper or metal wire around the pencil, from the eraser end to the pointed end.
- Slide the coil almost all the way off, and then continue winding the coil around the pencil once more.
- When you have a good length of wire coil, cut it loose from the rest of the copper or metal wire in the package.
- Take the coil off of the pencil. It should be quite uniform in tightness and diameter, or this is not going to work.
- Thread the lead through the center of your coil and let them dangle loosely for the time being.
- Encircle your coil around your conductor, making sure that the coil touches nothing but the conductor.
- Take the two lead ends that are dangling and attach them to the integrator circuit's end leads.
- Use the electrical power source you have chosen to give the conductor a little jolt.
You should notice a flow of current through the integrator circuit and a register of power output, especially if your integrator circuit has a built-in meter for such things.