Abstract

Objective

The objective of this project is to build a simple electric motor from scratch.

Introduction

Electric motors are everywhere; even your computer has electric motors to power its cooling fans and hard disks. Building a simple DC electric motor is a great way to learn how they work, and it's really fun to watch your creation spin.

Terms, Concepts, and Questions to Start Background Research

To do an experiment in this area, you should do research that enables you to understand the following terms and concepts:

• armature or rotor,
• commutator,
• brushes,
• field magnet,
• electromagnet, and
• the operating principles of a DC motor.

More advanced students will also want to study:

• right-hand rule,
• induction, and
• back EMF.

Bibliography

Here are some resources to get you started:

• How Electric Motors Work:  http://electronics.howstuffworks.com/motor.htm
• Simple Electric Motors:  http://www.simplemotor.com/

Find instructions for the simple motor described below at any of these sites:

• http://www.scitoys.com/scitoys/scitoys/electro/electro.html#motor
• http://www.partsgeek.com/mmparts/understanding_motors.html
• http://fly.hiwaay.net/~palmer/motor.html

Experimental Procedure

Make sure you scroll to the bottom of the above window if you're not seeing the complete instructions.

The source for the above experimental procedure is Science Toys You Can Make with Your Kids (Field, 2002).

If you are having problems, try the following: "Give the coil a spin to start it turning. If it doesn't keep spinning on its own, check to make sure that the coil assembly is well balanced when spinning, that the enamel has been thoroughly scraped off if enameled wire has been used [you'll see a slight change in color; the bare copper will be slightly brighter than the enameled copper], ... and that the coil and the magnet are close to each other but do not hit each other. You might also try adjusting the distance separating the cradles [armature supports]: This may affect the quality of the contact between the coil and the cradles [armature supports]." (Exploratorium, date unknown)

Variations

Building a motor is your first step, to make a good science fair experiment, you should investigate some of the following questions:

• What is the effect on the motor of changing the battery voltage?
• "Try making different shaped coils and seeing how they work. Is the circle the best shape? Try squares, ovals, etc. Make a display showing each of the coils you tried with a short summary of the results underneath them" (Palmer, date unknown).
• "Turn the coil slowly by hand and feel the magnetic attraction at each position of the coil. Make drawings showing the different coil positions and describe how the attractions vary at each position" (Palmer, date unknown).

• For more science project ideas in this area of science, see Electricity & Electronics Project Ideas.

Credits

Field, S. Q., 2002. "Science Toys You Can Make with Your Kids," SciToys.com [accessed November 21, 2004] http://www.scitoys.com/scitoys/scitoys/electro/electro.html#motor.

Exploratorium, date unknown. "Science Snacks: Stripped Down Motor," The Exploratorium [accessed September 27, 2010] http://www.exploratorium.edu/snacks/stripped_down_motor/.

Palmer, C.M., date unknown. "Beakman's Electric Motor," [accessed November 21, 2004] http://fly.hiwaay.net/~palmer/motor.html.

Last edit date: 2010-09-27 10:00:00