Project
by Richard Panosh
A Simple Shaded
Pole AC Motor
This Month’s
Projects
Pole AC Motor . . . . .36
Ever-Shrinking µC . . 42
Calculating Current . . 50
The Fuzzball
Rating System
To find out the level
of difficulty for
each of these
projects, turn to
Fuzzball for
the answers.
The scale is from
1-4, with four
Fuzzballs being
the more difficult
or advanced
projects. Just look
for the Fuzzballs in
the opening header.
You’ll also find
information included
in each article on
any special tools
or skills you’ll
need to complete
the project.
Let the
soldering begin!
How Could Tesla Be Wrong?
As early as 1821, Michael Faraday
demonstrated that continuous rotary
motion could be produced by passing
a DC (Direct Current) current through a wire
in the presence of a magnetic field.
Many pioneers followed in his footsteps,
but failed to develop a commercially successful
DC motor. Development was hampered
because batteries were the only source of
electrical power. Batteries, while large and
heavy, were constructed from expensive
materials that could provide little energy. As a
result, electric power was unable to compete
with the current technology — steam power.
Steam could be obtained cheaply from just
water and coal-fired boilers. Thus, funding
for the development of electric motors was
nonexistent and they were relegated to being
laboratory curiosities.
Further development of electric motors
was delayed until the 1870s, when a number
of experimenters developed the principle of
the self-excited DC generator. At this time,
they discovered the reciprocity theorem, in
which a motor could act as a generator or vise
versa. This discovery was widely publicized in
1873 by the French engineer, Hippolyte
Fontaine, who recorded the results of an
Figure 1. A capacitor produces a phase shifted field.
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NUTS & VOLTS
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accident where a worker mistakenly wired two
generators together.
DC generators rapidly replaced the energy
deficient batteries with a source of endless
electric power. Steam power was now
harnessed to drive these generators. The
transmission of electric power permitted these
plants to be located farther away so that noise
and pollution were hidden.
Countless small DC motors were rapidly
introduced to power fans, sewing machines,
and other light tasks for the upper class. Cities
had grown into heavily populated metropolises
and a cleaner and cheaper means of transportation was desired to replace the horse-drawn buggy. In 1897, thousands of visitors at
Germany’s Berlin Exhibition were transported
by the first practical electrically-powered
motor vehicle, developed by Werner von
Siemens.
Many companies began with the production
of electrically-powered cars from about 1897
to 1914. In 1898, 23-year-old Ferdinand
Porsche landed his first job in the automotive
field with Jacob Lohner. He devised a system
to eliminate the conventional front wheel
hubs, transmission, gears, and chains by
installing electric motors integral to each front
wheel hub. In 1900, this car made its debut
at the World’s Fair in Paris, France and went
on to set several Austrian land speed records.
Porsche realized that the weight and the
storage capacity of batteries were serious
limitations, but he also recognized the advantage of electric motors to be quiet, smooth,
and very reliable. After the exposition, he
designed a car that employed an internal
combustion engine to drive a generator that,
in turn, supplied the electrical power to the
twin hub motors. This is a century before
Honda, Toyota, and others would introduce
their hybrids.
In spite of the great accomplishments,
further applications of DC motors were limited
since DC power could only be transmitted a
JANUARY 2005
