The silver state news. [volume] (Winnemucca, Nev.) 1907-1909, 1909-01-12

&O1AHA " -
life Of the cell would be very short III
an electric bell be introduced INTO 'he
e;ycu;t the external resistance mlgn,
amount TO 1.25 ohns. This, with the
% ohms internal resistance Woul1
make Is ohms for the total resistance
Is volts divided by Is ohms gives 1
ampere current. With the smaller eur
rent and with only occasional use OF ~
the life of the cell may possibly extend
a year.
The Edison primary battery IS one
Of the most efficient on the market.
Its electro motive-foree is about y AM
its internal resistance is extremely low.
The large size Edison battery has a re-
s;stanee of only 90 ohms. Its maxi
mum current is 80 amperes and IT can
keep up continuous current Of 7 am
peres. Its total capacity is 500 ampere
beurs. Many forms Of cells have been
invented and are on the market but We
have described only two for the dyna-
mo as a source Of currents has displae-
cd the ~voltaie cell except for minor
uses.
The DYNAMO is a machine in which
mechanical energy is transformed into
the energy Of electric current by means
of magneto-eleetrie Induction. Mag
neto-electrie induction is the influence
by which a moving magnet induces
electric currents in closed circuits.
If batteries were used for generating
currents for electric lighting, running
motors. etc. they would have to be
very large and costly and would con-
stme so much zinc and acid as to be
very expensive. On this account com
paratively few applications of hIga
power currents were practicable until
the inventing of the dynamo.
II will be remembered that Oersted's
great experiment proved that cleo
~trieity in motion acquired a property
not possessed by electricity at rest.
The electric current developed a mag
netie field OF force about it as was
seen by it's ability to defect a mag
netic needle held near it. Faraday in
ngland. and Henry in this country,
working Independently, discovered that
this experiment could be "worked
backwards" that is, that a moving
magnetic field or a magnetic field that
is either increasing or decreasing in
intensity, develops an electro motive
force and hence is able to produce a
current in a closed circuit. Upon this
principle is based the modern dynamo.
The machine consists of a powerful
magnet or set of powerful magnets 10
furnish the magnetic field of force.
This set of magnets is generally spok
en- Of as the 'tfeld.' IL is. of course.
immaterial whether these magnets be
permanent magnets, or electro magnets.
Except, however, in the case of small
machines called "magnetos," the mas
nets are always electromagnetic be.
cause these can be made so much more
powerful than permanent magnets.
A great bundle of insulated copper
wire wound in loops furnishes the
closed circuit in which the electro
motive-foree is d~evelopend. This 10
called the Harmatureu
The alternately directed currents
generated y the successive approach
and recession of the coils to and from
the fixed magnetic poles may be com
muted, that is, by means of a device
called the "eommutator," they pass
into the external circuit a one.way or
direct current. A dynamo with n
commutator is a direct current dynamo,
without it, it is an alternating eur
rent dynamo.
In direct current dynamos, il Ia
to rotate the armature with
in the field, but in the alternating cur
rent dynamos which generally have a
frequency Of so, and generate an
eleetro-motive-force from 1000 to 5000
volts. the field magnet is made to ro-
tate about the armature. This is be-
cause perfect insulation between the
coils in the armature is required and
with such high voltage it is more
easily obtained when the armature Is
stationary.
II will be remembered that the mag
nitude of the electro motive-force
developed in a battery is not depend.
ent upon the size of the battery but
solely upon the chemical relation be.
tween the electrodes or plates and the
electrolyte or acid. But increase of
size in batteries does decrease their
internal resistance and thus enable
them to yield a larger current. The
Edison cell is made in five sizes, all of
which have an initial electro motive.
force of .95 volts but, while the small
est gives a maximum current Of TAO
IN e. L.