A simple handmade motor is a commonly used teaching aid for explaining the theory of the DC motor in science classes around the world. Kits that can be used by children to craft a simple motor are commercially available, and videos of assembling these motors are easily found on the internet. Although the design of this motor is simple, it is unipolar, meaning that the rotor consists of a single dipole. Thus, the Lorentz force acts only on one side of the coil per revolution. This decreases the energy conversion efficiency and requires the learners to turn the rotor using their hands in order to initiate rotation.

1.
Kristy Beauvais, Research Experience for Teachers, Center for Materials Science and Engineering
, “
The Simple DC Motor: A Teacher’s Guide
” (
Massachusetts Institute of Technology
,
Aug.
2003
); http://web.mit.edu/cmse/educational/motor_lp_kristy.pdf.
2.
World’s Simplest Motor™
,
EYeany Educational Products
. Available from Amazon.com #DOP-10A for $8.99.
3.
Arthur F.
Klittnick
and
Malcolm J.
Rickard
, “
Mystery motor demystified
,”
Phys. Teach.
39
,
174
175
(
May
2001
).
4.
Kei
Eguchi
 et al, “
Practical classes using paper clip electric motor with rotating image
,”
J. Japan Soc. Technol. Educ.
53
,
161
167
(
2011
).
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