It is difficult to estimate the effect of an invention
on existing practices and industries. Occasionally a new invention will appear
which will greatly affect a whole range of allied inventions and industries in
such a way as to entirely change time-honored customs, inaugurate new practices
and establish new arts. The commercial development of electricity is a notable
example of this.
After Mr. Brush successfully accomplished practical electric illumination by
means of arc lights, incandescent lighting was quickly brought forward and
rapidly perfected. Gas lighting was also improved in various ways.
Simultaneously with these, the electric distribution of power was carried
forward, and important improvements were made in prime movers for driving
dynamos.
In this direction much has been done both in steam and water motors. Wind
power has been repeatedly suggested for driving dynamos, but the adaptation of
the windmill to this use seems to have been a problem fraught with
difficulties.
Few have dared to grapple with it, for the question not only involved the
motive power itself and the dynamo, but also the means of transmitting the power
of the wheel to the dynamo, and apparatus for regulating, storing and utilizing
the current.
With the exception of the gigantic windmill and electric plant shown in our
engraving, we do not know of a successful system of electric lighting operated
by means of wind power.
The mill here shown, as well as all of the electrical apparatus used in
connection with it, and the very complete system by which the results are
secured, have been designed and carried out according to the plans of Mr.
Charles F. Brush, of Cleveland, Ohio, and under his own personal supervision. As
an example of thoroughgoing engineering work it cannot be excelled.
Every contingency is provided for, and the apparatus, from the huge wheel
down to the current regulator, is entirely automatic.
The reader must not suppose that electric lighting by means of power supplied
in this way is cheap because the wind costs nothing. On the contrary, the cost
of the plant is so great as to more than offset the cheapness of the motive
power. However, there is a great satisfaction in making use of one of nature's
most unruly motive agents.
Passing along Euclid Avenue in the beautiful city of Cleveland, one will notice
the magnificent residence of Mr. Brush, behind which and some distance down the
park may be seen, mounted on a high tower, the immense wheel which drives the
electric plant to which we have referred. The tower is rectangular in form and
about 60 feet high.
It is mounted on a wrought iron gudgeon 14 inches in diameter and which
extends 8 feet into the solid masonry below the ground level. The gudgeon
projects 12 feet above the ground and enters boxes in the iron frame of the
tower, the weight of the tower, which is 80,000 pounds, being borne by a step
resting on the top of the gudgeon. The step is secured to a heavy spider
fastened to the lower part of the frame of the tower.
In the upper part of the tower is journaled the main wheel shaft. This shaft is
20 feet long and 6 1/2 inches in diameter. It is provided with self-oiling boxes
26 inches long, and carries the main pulley, which has a diameter of 8 feet and
a face of 32 inches.
The wheel, which is 56 feet in diameter, is secured to the shaft and is
provided with 144 blades, which are twisted like those of screw propellers.
The sail surface of the wheel is about 1,800 square feet, the length of
the tail which turns the wheel towards the wind is 60 feet, and its width is 20
feet. The mill is made automatic by an auxiliary vane extending from one side,
and serving to turn the wheel edgewise to the wind during a heavy gale.
The tail may be folded against the tower parallel with the wheel, so as
to present the edge of the wheel to the wind when the machinery is not in use.
The countershaft arranged below the wheel shaft is 3 1/2 inches in
diameter, it carries a pulley 16 inches in diameter, with a face of 32 inches,
which receives the main belt from the 8 foot pulley on the wheel shaft. This is
a double belt 32 inches wide.
The countershaft is provided with two driving pulleys each 6 feet in
diameter, with a face of 6 1/2 inches, and the dynamo is furnished on opposite
ends of the armature shaft with pulleys which receive belts from the drive
wheels on the countershaft.
The dynamo, which is on of Mr. Brush's own design, is mounted on a vertically
sliding support and partially counterbalanced by a weighted lever.
It will be seen that the countershaft is suspended from the main shaft by the
main belt, and the dynamo is partly suspended from the countershaft by the
driving belts. In this way the proper tension of the belts is always secured,
the total load on the dynamo belts being 1,200 pounds, and on the main belt
4,200 pounds.
The ends of the countershaft are journaled in sliding boxes connected by
equalizing levers which cause both ends of the shaft to move alike.
The pulleys are so proportioned that the dynamo makes fifty revolutions to
one of the wheel. The speed of the dynamo at full load is 500 revolutions per
minute, and its normal capacity at full load is 12,000 watts.
The automatic switching devices are arranged so that the dynamo goes into
effective action at 330 revolutions a minute, and an automatic regulator is
provided which does not permit the electromotive force to run above 90 volts at
any speed. The working circuit is arranged to automatically close at 75 volts
and open at 70 volts. The brushes on the dynamo are rocked automatically as the
load changes.
The field of the dynamo is slightly compounded. The current passes from the
dynamo to contact shoes of polished and hardened steel carried by a crossbar on
the tower, which shoes slide on annular plates surrounding the gudgeon.
Conductors extend underground from these plates to the dwelling house.
To guard against extraordinary wind pressure, the tower is provided at each
of its corners with an arm projecting downwardly and outwardly, and carrying a
caster wheel very near but not in contact with the circular rail concentric with
the gudgeon.
Ordinarily, the caster wheels do not touch the rail, but when the wind is
very high, they come into contact with the rail and relieve the gudgeon from
further strain.
In the basement of Mr. Brush's house there are 408 secondary battery cells
arranged in twelve batteries of 34 cells each; these 12 batteries are charged
and discharged in parallel; each cell has a capacity of 100 ampere hours.
The jars which contain the elements of the battery are of glass, and each
cell has its liquid covered with a layer of "mineral seal" oil, a
quarter of an inch thick, which entirely prevents evaporation and spraying, and
suppresses all odor.
The automatic regulating devices are shown in one of the views of our
engraving. At 1 are shown the voltmeters and ammeters employed in measuring the
charging and discharging currents; at 2 is shown a series of indicators, one for
each battery; 3 represents an electrically operated switch by means of which the
current may be turned on or off the house mains by pressing push buttons in
different portions of the house; 4 represents a ground detector, which is
connected with the center of the battery and with the ground, so that should the
conductor upon either end of the battery be grounded, the fact will be indicated
by the movement of the index in one direction or the other from the zero point
of the scale, thus showing not only that the battery is grounded, but indicating
the grounded pole; 5 is a leakage detector connected up with the lamp circuits,
and arranged to show any leakage from one conductor to the other; at 6 is shown
a compound relay for operating the automatic resistance shown at 7.
This resistance is placed between the batteries and the house mains,
and is arranged to keep the voltage on the lamps constant at all times. In this
device the resistance is secured by means of powdered carbon placed under
varying pressure, the necessary movement being made by means of hydraulic
pressure under the control of the relays.
The house is furnished with 350 incandescent lights, varying from 10 to 50
candle power each. The lamps most commonly used are from 16 to 20 candle power;
about 100 incandescent lamps are in everyday use. In addition to these lights
there are two arc lights and three electric motors.
It is found after continued use of this electric plant that the amount of
attention required to keep it in working condition is practically nothing. It
has been in constant operation more than two years, and has proved in every
respect a complete success.
The Journal of Wind Electricity
Copyright 1997-2003 Danish Wind Industry Association
Askov Folk High School still exists. Presently a non-profit association, the Poul la Cour Museum, is trying to collect funds to preserve Poul la Cour's original windmill Photographs © 2000 Poul la Cour Museet
