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Generators
A drawing of an electrostatics experiment by English scientist Francis
Hauksbee, using an early electrostatic generator of his design, drawn by
French clergyman and scientist Jean-Antoine Nollet, from his 1767 book
Leçons de Physique.
The genesis of generators
By Robyn Grimsley
Generators convert mechanical energy into electrical energy — an invention that has proved particularly useful to the
equipment industries. Generators as we know them today can be traced back to the work of English scientist Michael
Faraday, who discovered the operating principles of electromagnetic generators in the early 1830s.
P
eople have been aware of electricity in
one form or another since ancient times,
long before English scientist William
Gilbert coined the term electricus (from elektron,
the Greek word for ‘amber’) in his De Magnete
in 1600. While this is the origin of the English
word ‘electricity’, it was not until nearly half
a century later, in 1646, that the term first
made its way into print in Thomas Browne’s
Pseudodoxia Epidemica.
According to Schiffer (2003), in addition to
being behind the word ‘electricity’, Gilbert was
responsible for carrying out the first sustained,
influential research on electrical phenomena.
Gilbert’s experiments were followed by those
of Robert Boyle, widely regarded today as the
first modern chemist and a pioneer of the
experimental scientific method. In the mid-
1660s, Otto von Guericke created the first
electrostatic generator: a sulphur ball on an axis
mounted in a wooden frame, which could be
rubbed to generate charge (static electricity).
Francis Hauksbee improved the basic design
of Guericke’s generator through use of his
frictional electrical machine, which enabled
a glass sphere to be rotated rapidly against a
woollen cloth.
Experiments with electric machines were
aided significantly by the discovery of the
Leyden (or Leiden) Jar, an early form of the
capacitor, in the mid-eighteenth century. The
Leyden Jar allows for the accumulation of an
electrical charge when connected with a source
of electromotive force.
Over time, friction machines were slowly
replaced by influence machines, which
operate via electrostatic induction, converting
mechanical work into electrostatic energy by a
small, continually replenished and reinforced
initial charge. The Wimshurst machine was a
version of the electrostatic disc machine that
was invented by James Wimshurst in the early
1880s, and which induced electrostatic charge
with two plexi-glass contra-rotary discs that
caused friction with a metal foil section.
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