How
real electric motors work
John
Storey
Note:
These pages are intended to be read in conjunction with
Joe's "Electric
motors and generators" pages of the HSC Physics
resources. Read those pages first. Once you've got the basic
idea and understand the physical principles and the maths,
you're ready to explore how real-life engineers have put
physics into action to make our lives easier.
When
it comes down to it, all these motor are using the same
basic principle. In some cases, it’s easiest to think
in terms of the force on a current-carrying wire in a static
magnetic field. In other cases it’s easiest to think
about two magnets (at least one of which is an electromagnet)
attempting to align their poles north-to-south and south-to-north.
However, both these explanations amount to the same thing,
as James Clerk Maxwell so elegantly described with his four
equations that form the basis of electromagnetism.
If
you're tempted to pull a motor apart yourself, please think
carefully about the risks involved before reaching for the
tool kit. Some of the more important risks
are listed at the end of this article. Also see Richard's
page on Faraday's
Law which contains an activity on "Building a motor
and electrical generator".
Click
on any picture for a high-resolution image. All pictures
may be freely reproduced for educational purposes provided
they are appropriately acknowledged.
You
can download this entire document as a 2.3 MB PDF
file , or read individual sections by following the
links.
