How to Build an Electromagnetic Motor
Build an electromagnetic motor for the classroom to demonstrate the principles that make a motor work. This project is inexpensive and does not take a lot of time to put together for the students. Make sure that you test this out before you let the students see it.
Things You'll Need
- Needle
- Round cork
- 22 gauge magnet wire
- 2 pair of pliers
- Cardboard
- 2 hollow rivets & riveting gun
- 9 volt battery
- Duct tape
- Button magnet (as strong as you can get)
Instructions
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1
Draw a line around the cork that that bisects the cork into two equal sides. Cut a groove a half centimeter wide and a quarter centimeter deep on this line. Wind the 22 gauge wire around the groove in one direction 50 times. Leave the ends of the wire sticking out at each end of the cork 1cm.
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2
Snap the large sewing needle in half with two pair of pliers. Insert a piece of the needle in the top and bottom ends of the the cork so that it sticks out at both ends 3cm, but not touching each other (even inside the cork). Sand the insulation off of the magnet wire and use a very small piece of tape to hold the two ends of wire each to a different needle half.
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3
Cut the cardboard into a long strip (3 inches wide by 9 inches long). Measure the distance from one tip of the broken needle at one end to the tip of the other half of the needle at the far end. Take this distance and subtract 4cm for the length of the motor housing.
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4
In the cardboard, fold a piece the length you just measured with flaps on either side that are of equal length. Glue the button magnet onto the center of the motor housing base (between the two folds). In the side flaps of cardboard, use a pencil to mark the position where the holes for the needles should be drilled so that the motor can spin freely above the magnet.
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5
Use a pair of scissors to poke/drill a hole in the marks on the side flaps. Strip two 9-inch lengths of wire at both ends by sanding off the insulation (using more 22 gauge wire). Use a rivet gun in the holes that you have made to clamp down rivets over a 9-inch wire at each hole. Insert the needles into the hollow centers of the two rivets and fold the side flaps so that they encase the top of the motor. Duct tape these outermost flaps together over the motor with enough space to let the motor spin freely. Trim off the excess.
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6
Test the motor by running the two wires from the rivets to the leads on a nine volt battery.
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Tips & Warnings
Give the motor a small push to get it going, add more current or get a stronger magnet if the motor fails to perform. Make sure that the magnet is not very far from the coils of wire on the cork because magnets lose their power exponentially as the distance increases between magnetic fields. Also make sure that the insulation is properly stripped (a pair of scissors or sand paper work well) before attaching them to their connections. Make sure that the rivets conduct electricity before using them. If you do not want to buy a rivet gun, try lining the holes for the needle-axle with aluminum foil instead.
Do not hurt yourself with the tools. Wear safety glasses. Read and follow all safety information provided with your equipment/tools. If you add more current, do not trust any connections to be safe to touch or to get wet. With higher current also comes the possibility that the wires will heat up and there is an increased risk of fire, so be cautious.
