<h2><SPAN name="CHAPTER_XXIII" id="CHAPTER_XXIII"></SPAN>CHAPTER XXIII.</h2>
<h3>NIAGARA FALLS POWER—APPLIANCES.</h3>
<p>Some years ago a company was formed for
the purpose of utilizing, to some extent, this
greatest of all water-powers. A tunnel of large
capacity was run from a point a short distance
below the falls on a level a little above
the river at that point. The general direction
of this tunnel is up the river; it is about a
mile and one-half in length, terminating at a
point near the bank of the river a mile or more
above the falls. Above the end of this tunnel
an upright pit comes to the surface, where
a power-house of large dimensions has been
constructed of solid masonry. It is long
enough at present to contain ten dynamos of
mammoth size. Along the side of this power-house
a deep broad canal is cut, which communicates
with the river at that point, and
through which flows the water that is to furnish
the power. Of course the water level of
this canal is the same as that of the river.</p>
<p>The foundations of the power-house extend
to the bottom of the tunnel, which at that
point is 180 feet below the surface of the<span class="pagenum"><SPAN name="Page_191" id="Page_191"></SPAN></span>
ground. To put it in other words, the cellar
or pit under the power-house is 180 feet deep
and communicates with the great tunnel,
which has its outlet below the falls.</p>
<p>Each of the ten dynamos is driven by a turbine
water-wheel situated near the bottom of
the pit heretofore described. The turbine-wheel
is on the lower end of a continuous
shaft, which reaches from a point near the
bottom of the tunnel to a point ten or fifteen
feet above the floor of the power-house (which
is about on a level with the surface of the
ground).</p>
<p>This shaft is incased in a water-tight cylinder
of such diameter as will admit a sufficient
amount of water, and connects with the turbine
wheel at the bottom in the ordinary way.
The water is admitted into the top of this
cylinder from the canal, so that the wheel is
under the pressure of a falling column of
water over 140 feet high. The water, forcing
its way out at the bottom through the turbine,
revolves it and its long, upward-reaching shaft
with great power, and enables it to work the
dynamos in the power-house above, as will be
described. The water discharges through the
wheel in such a manner as to lift the whole
shaft, thus taking away the tremendous end-thrust
downward that would otherwise interfere
greatly with the running of the machine
through friction. After the water has done<span class="pagenum"><SPAN name="Page_192" id="Page_192"></SPAN></span>
its work it flows off through the tunnel into the
river below the falls.</p>
<p>To the upper end of the power-shaft is attached
a great revolving umbrella-shaped
hood; to the periphery (circumference) of
this hood is attached a forged steel ring, 5
inches in thickness, about 12 feet in diameter
and from 4 to 5 feet in width. The whole of
the revolving portion—including the ring upon
which are mounted the field-magnets, the
hood, and the shaft running to the bottom of
the pit, where the turbine wheel is attached—weighs
about thirty-five tons.</p>
<p>The dynamos belong to the alternating type,
and are comparatively simple in construction.
In a previous chapter upon the dynamo it was
stated that the fundamental feature was the
relation that the field-magnet and the armature
sustained to each other, and that in some
cases the field-magnet revolves while the part
that is technically called the armature remains
stationary. In other cases the armature revolves
and the field-magnets are stationary.
In the latter case brushes and commutators
are used, to catch and transfer the generated
electricity, while in the former these are not
needed, which simplifies the construction of
the machine.</p>
<p>As we have stated, the dynamos used at
Niagara are constructed with revolving field-magnets
that are bolted on to the inner surface<span class="pagenum"><SPAN name="Page_193" id="Page_193"></SPAN></span>
of the steel ring that is carried by the hood,
so that there are no brushes connected with the
machine except the small ones used to carry
the current to the field-magnets.</p>
<p>The current for power purposes is generated
in a large stationary armature about ten feet
in diameter and of the same depth as the revolving
ring. The revolutions of the ring send
out currents of alternating polarity, and each
of the ten machines will furnish electrical
energy equal to 5000 horse-power, so that when
the work that is now under way is completed
50,000 horse-power can be furnished in the
form of electricity. About 35,000 horse-power
is now actually delivered to the various industrial
enterprises. The dynamos are set horizontally,
since the shaft which connects them
with the turbine wheel stands in a perpendicular
position.</p>
<p>Not all of the energy that is developed by
the water-wheel is converted into electricity,
but some of it appears as heat. In order to
prevent the heat from becoming so great as to
be dangerous to the machine it must be constructed
in such a way as to admit of sufficient
ventilation for cooling purposes. The armature
is so constructed that there are air-passages
running all through it, and on top of
the revolving hood are two bonnet-shaped air-tubes
set in such a way as to force the air
down through the armature, which carries off<span class="pagenum"><SPAN name="Page_194" id="Page_194"></SPAN></span>
the heat and warms the power-house, on the
principle of a hot-air furnace. This great
machine—which, in a way, is so simple in its
construction—when in action conveys to the
mind of the beholder a sense of wonderful
power. It is only when we stand in the presence
of such exhibitions as may be seen in this
power-house, devised and executed by the
genius of man, and in that greater presence,
the mighty Falls of Niagara, that we get something
of a conception of the power of the silent
yet potent energy of the great king of daylight,
the sun.</p>
<p>There are very many interesting details that
work in connection with this great power-plant,
some of which we will describe, in a general
way.</p>
<p>Standing within a few feet of each one of
the great dynamos is a very beautifully constructed
piece of machinery called the governor.
The governor regulates the speed of
the dynamos by partially opening and closing
the water-gates that regulate the flow of water
into the turbines. The question may be asked,
why is there any regulation needed, if there is
always an even head of water? There are two
reasons—one because the load on the dynamo
is constantly changing, and another that the
head of water changes, although this latter
fluctuation is in long periods. If the circuit
leading out from the dynamo is broken, the<span class="pagenum"><SPAN name="Page_195" id="Page_195"></SPAN></span>
rotating part of the dynamo will move with
great ease and little power, as compared with
what is required when the circuit is closed,
and the current is going out and doing work.
The increased amount of energy that will be
required to keep the dynamo moving at a certain
rate of speed when the load is on—in
other words, when the circuit is closed—will
depend upon the amount of current that is going
out from the dynamo to perform work at
other points. As the amount of current used
outside for the various purposes is constantly
changing, it follows that the load on the
dynamo is constantly changing also. As the
load changes, the speed will change, unless the
amount of water that is flowing into the turbine
is changed in a like proportion; hence
the necessity for a governor that will perform
this work. You can easily imagine that it will
require a great amount of power to move the
gate up or down with such a pressure of water
behind it. It is not possible here to explain
the operation of the governor in detail, as that
could not be done without elaborate drawings;
suffice it to say that the whole thing is controlled
by a small ball governor such as we see
used in ordinary steam-engines for regulating
steam-pressure.</p>
<p>The rising or falling of the balls of this
governor to only a very slight extent will
bring into action a power that is driven by<span class="pagenum"><SPAN name="Page_196" id="Page_196"></SPAN></span>
the turbine itself, which is able to move the
water-gate in either direction according as
the balls rise or fall. For instance, if the balls
rise beyond their normal position, it shows
that the dynamo is increasing in speed, and
immediately machinery is brought into action
that shuts the water off in a small degree, just
enough to bring the speed back to normal. If
the balls drop to any extent, it shows that the
load is too great for the amount of water, and
that the dynamo is decreasing in speed; immediately
the power is brought into action,
now in the opposite direction, and the water-gate
is opened wider. These slight variations
of speed are constantly going on, and the constant
opening and closing of the gate follows
with them. It is a beautiful piece of machinery,
and is beautifully adapted to the
work it has to perform. It is continually
standing guard over this greater piece of
machinery that is exerting an energy of 5000
horse-power and prevents it from going wrong,
both in doing "that which it should not do
and leaving undone that which it should do."
It is a machine that, when in action, points a
moral to every thinking person who beholds it.
Every man has such a governor if he only has
the inclination to use it.</p>
<p>I have said further back that the water-head
varies, but usually at long periods. This
variation is chiefly caused by changes of<span class="pagenum"><SPAN name="Page_197" id="Page_197"></SPAN></span>
wind, and it is very much greater than one
would suppose without studying the causes.
Lake Erie lies in an easterly and westerly direction,
and when the wind blows constantly
for a time from the west, with considerable
force, the water piles up at the eastern end of
the lake, which causes the level of the Niagara
River to rise to a very sensible extent. It is
not so noticeable above the falls as below, because
of the great difference in the width of
the river at these two points. Sometimes the
river below the falls, as it flows through the
narrow gorge, will vary in height from twenty
to forty feet. When the wind stops blowing
from the west and suddenly changes and blows
from the east, it carries the water of the lake
away from the east toward the west end, which
will produce a corresponding depression in the
Niagara River. No doubt there is an effect
produced by the difference of annual rainfall,
but the effect from this cause is not so marked
as that from the changing winds.</p>
<p>Another appliance used in the power-house,
chiefly for handling heavy loads and transferring
them from one point to another, is
called the electric crane. It is mounted upon
tracks located on each side of the power-house.
The crane spans the whole distance, and runs
on this track by means of trucks from one end
of the power-house to the other. Running
across this crane is another track which car<span class="pagenum"><SPAN name="Page_198" id="Page_198"></SPAN></span>ries
the lifting-machinery, consisting of block
and tackle, able to sustain a weight of fifty
tons. Situated at one end of the crane are
one or more electric motors, which are able,
under the control of the engineer, to produce
a motion in any direction, which is the resultant
of a compound motion of the two cars
acting crosswise to each other together with
the perpendicular motion of the lifting-rope
connected with the block and tackle. It seems
like a thing endowed with human reason, when
we see it move off to a distant part of the
building, reach down and pick up a piece of
metal weighing several tons, carry it to some
other portion of the building and lower it into
place, to the fraction of an inch. While the
machine itself does not reason, there is a reasoning
being at the helm, who controls it and
makes it subservient to his will. The machine
is to the engineer who manipulates it what a
man's brain is to the man himself. The brain
is the instrument through which the unseen
man expresses his will and impresses his work
upon men and things in the visible world.</p>
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