Cottonwood report. [volume] (Cottonwood, Idaho) 1893-1901, 1894-02-23
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| having a horseshoe magne
naper placed in horizontal ll9<
loosely sprinkling iron filings around the
ends it can be seen that there is an appar-N
ent current of this influence projecting
into space from the ends and running
across the space at the open ends of the
magnet. These imaginary projections or
currents of this mysterious influence are
called "lines of magnetic force"
Here we have the magnetic force, and
the next thing is to get the electricity. By
moving an armature across these lines OF
magnetic force at the ends of magnet
we find it requires an expenditure Of
energy. In the case of dynamo we obtain
this energy from steam, water power OF
some other source The generation Of
electricity is as easily understood as the
method of getting power by steam en-
CINE. 1t is known that if we take con
ductor of electricity, like common cop
per wire, and by any means cause it &c
move through lines of magnetic force in
certain direction, that electricity will be
developed in this conductor. No one pre-
tends to explain why. This is the whole
mystery of the dynamo, with all its as.
tonishing possibilities in the service OF
man.
in mystery about the reason nature acts
in this way as we are to explain why an
apple goes down instead of up when rolled
from your open hand.
A dynamo consists principally of two
parts, one Of which is large mass of soft
cast or wrought iron called the magnet,
and the other part is called the armature.
Soft iron does not remain permanently as
magnet except to very slight degree.
However, some magnetism always remains
stored up in the iron. There is germ of
magnetism great enough to be easily and
quickly increased when properly handled
| by well known methods. The revolving
shaft, as seen in the ordinary dynamo, is
called the armature The armature is
usually constructed by having hundreds
of insulated copper wires in it and is made
to revolve at a high velocity by some me-
chanical force, such as steam. Suppose
this speed is 1000 revolutions per minute,
which is not unusual, and that we have
500 wires on this armature, then we will
have, as the armature revolves, what
would be equivalent to single wire cut
| ting across all the lines of magnetic force
100000 times each minute.
The magnet generally surrounds the
armature, and these magnetic lines Of
force are shooting through the armature
| in continuous stream at an inconceivable
velocity. All the wire conductors on the
revolving armature, as they move through
| these lines of magnetic force, are constant
ly picking up their little share of electric
ity and unloading it by means of ingen-
ious mechanical devices connecting with
the conducting wire that leads from the
| dynamo, and receiving the returning cleo
tricity on another wire leading back into
the dynamo.
One of natures wonderfully mysterious
laws causes soft iron to become magnetic
when surrounded by current of cleo
tricity. In the ordinary dynamo this law
is of the greatest utility. AS the electrical
current is being collected by the revolving
armature it is led around the magnet, and
thus the magnetic germ is quickly changed
into a mighty force, again feeding the
armature which transforms it from mag.
netic to electrical force.-Mechanica and
Electrical Progress.