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Engineering Your Future

Electrical and Computer Engineering

Summer 1999

Carnegie Mellon University

As part of the Engineering Your Future program at Carnegie Mellon University, high school girls spent a day building battery-powered DC motors. After a short discussion about current, magnets, motors and generators, each girl got a kit containing the parts for her motor. The kits were made by an 8th grader in Texas who did a prize-winning science project about motors. For more information on the motors (and how to get a kit for yourself), see his web page.

The high school girls worked in teams so that they could help each other out. They they built a rotor with two permanent magnets on it, and they made an electromagnet by winding copper wire around a large nail. Connecting the electromagnet through the reed switch to the battery was the most difficult part. Some of the motors worked the first time, but a lot had to be checked for loose connections, friction in the rotor, and weak electromagnets. Each girl got to take her motor home with her.

Assembling the Rotors

Coiling the Wire for the Electromagnet

Assembling the Reed Switch

Closing the Circuit