A Wind Energy Pioneer: Charles F. Brush
The Forgotten Wind Turbine Pioneer
All photographs on this page copyright © the Charles F. Brush Special Collection, Case Western Reserve University, Cleveland, Ohio.
Charles F. Brush
Charles F. Brush (1849-1929) is one of the founders of the American electrical industry.
He invented e.g. a very efficient DC dynamo used in the public electrical grid, the first commercial electrical arc light, and an efficient mehod for manufacturing lead-acid batteries. His company, Brush Electric in Cleveland, Ohio, was sold in 1889 and in 1892 it was merged with Edison General Electric Company under the name General Electric Company (GE).
The Giant Brush Windmill in Cleveland, Ohio
Brush Windmill 1888
Brush Windmill 1888 During the winter of 1887-88 Brush built what is today believed to be the first automatically operating wind turbine for electricity generation.
It was a giant - the World's largest - with a rotor diameter of 17 m (50 ft.) and 144 rotor blades made of cedar wood. Note the person mowing the lawn to the right of the wind turbine.
The turbine ran for 20 years and charged the batteries in the cellar of his mansion.
Despite the size of the turbine, the generator was only a 12 kW model. This is due to the fact that slowly rotating wind turbines of the American wind rose type do not have a particularly high average efficiency. It was the Dane Poul la Cour , who later discovered that fast rotating wind turbines with few rotor blades are more efficient for electricity production than slow moving wind turbines.
The Scientific American Article About the Brush Windmill Scientific American cover
20 December 1890 the journal Scientific American has a very detailed description of the Brush windmill. It is particularly noted for its fully automated electrical control system.
Its principles using solenoids does not change very much with future generations of wind turbines - until about 1980 when the wind turbine controllers become equipped with computers.
Mr. Brush's Windmill DynamoScientific American, 20 December 1890
(It is a good idea to click the picture above in order to have it next to this page, and follow the references in the article)
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.
© Copyright 1997-2003 Danish Wind Industry Association
Updated 23 July 2003
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