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CHAPTER XVII
DYNAMOS

 

 

 

 

 

THERE is perhaps no other electrical device entering into
the young experimenter’s domain requiring the careful
workmanship and tool facilities that the dynamo does.
In order to construct a practical working dynamo it would
be necessary to have at hand a lathe for turning the cast-
ings.

Rather than describe a machine which comparatively
few of my readers would be able to build, I have explained
below how it is possible to so alter an old telephone mag-
neto that it may be made to serve as a small dynamo.
Telephone magnetos, also sometimes called hand genera-
tors, are used in many telephone systems to supply the
current which rings the telephone bell at the other end.
The magneto is placed in a small box on the telephone,
only the handle being exposed. In order to make a call
the handle is given several brisk turns before raising the
receiver. When the handle is turned the. moving parts
of the generator revolve and produce a current of electric-
ity which goes forth over the line and rings the bell at the
other end.

Telephone magnetos are gradually being discarded in all

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