How Niagara Has Been "Harnessed"
By William C. Andrews
[This article appeared in The American Monthly Review of Reviews, June 1901. It is reproduced here in full.]
Early in 1886 a charter was obtained from the New York Legislature by several citizens of Niagara Falls, which had for its object the further development of the water-power. The recipients of this charter, which has since been amended and enlarged by many successive acts, were men who not only realized the commercial value of such development, but were opposed to the desecration of the most impressive natural object of the world for utilitarian purposes. The first formal plan upon which the future work was based was published on July 1 of that year, at which time about 10,000 horse-power was being used by the small mills situated on the bluff below the falls, and receiving their supply of water through a thirty-five-foot canal nearly a mile long, which looped around the cataract. In-stead of carrying the water below the falls, the new plans proposed its utilization above them, the waste water to be discharged through a tunnel passing deep under the town and opening unobtrusively into the lower river. This scheme had its inception in the mind of Mr. Thomas Evershed, an engineer, who for more than fifty years had been intimately connected with the Niagara River district as a public hydraulic en-gineer, and it was natural that in the development of his plans the underlying idea should have been the protection of Nature's beauty from commercial vandalism. As soon as the proposition to obtain a vast water-power development a mile above the falls and to connect it by as long a tunnel to the lower river was made public, it was agreed by many theorists and practical men as being feasible from neither a commercial nor mechanical standpoint. In the light of its future successful adoption the perusal of the many signed communications from apparently authoritative sources, which appeared in the magazines and journals of that period, denouncing the impracticability of the scheme, is amusingly in-teresting, especially from the prominence of some of the names on record; but at the time, this opposition was responsible for much delay in the securing of sufficient capital to commence the undertaking. For three years, therefore, the original promoters labored to convince financial circles of the commercial profit to be obtained, and it was not until 1889 that the Cataract Construction Company was formed, and investigations actually inaugurated as to the best means of transformation and transmission. After consulting the highest engineering authorities throughout the world and obtaining their personal investigation and inspection of the physical and commercial conditions, the company advertised an invitation for competitive plans and estimates for an electrical generating station at Niagara and a transmission system to Buffalo.
The visitor to the Falls this summer who re-turns after ten years' absence will find it hard to realize that in the interim the immense power supply with which he is familiar has been tapped, and that under his feet there rushes a torrent which has been diverted from its wasteful leap over the cliff and has been forced to turn the wheels of man. If, however, he will walk up the river to a point about opposite the lower end of Grass Island, he will find a new canal, 250 feet in width and 1,700 feet long, conducting a lazily flowing stream of water away from the main body and leading it to a handsome lime-stone building of pleasing though plain architec-tural design. On entering this building, he will discover that the interior is one long room, wherein are placed in a single row running centrally throughout the entire length ten mammoth electrical generators, revolving in all the majesty of inherent power. And this is the result of all the planning, and designing, the financiering and legislative deliberation; this is the central source from which the hundred new industries attracted to a new manufacturing center obtain their power, and upon which Buffalo, fifteen miles away, depends for the operation of many of its street railways and mills. That canal which so unostentatiously takes its fraction from the Niagara River has a capacity in its twelve feet of depth to serve the station with water sufficient for the generation of 100,000 horse-power, twice the capacity of the present electrical installation.
The power station is nearly 500 feet long, and is built over an excavation in the solid rock 178 feet deep, which runs its entire length-a mam-moth cellar. This is the wheel-pit wherein, at the bottom and directly under the dynamos in the room above, are placed the immense turbine water-wheels which change the energy stored in the falling water into mechanical rotation. The turbines and generators are directly connected by shafts made of 38-inch steel tubes, 3/8 inch in thick-ness, narrowing down to short, solid sections, occasional, to pass through guides which maintain the vertical alignment and terminating in 11 1/2-inch hollow-forged dynamo shafts at the upper end. The immense weight of this shaft and of the revolving parts of the water-wheels and dynamos is supported by the water impinging against the blades of the wheel and the upward thrust of the water against a balance piston, which is formed by the carrier of one of the rings of turbine blades or buckets. Any unbalanced vertical thrust is taken up by a thrust bearing near the dynamo floor. The pen-stocks, which conduct the water from the canal to the turbines, consist of 7 1/2-foot steel tubes running from the head gates at the surface to the turbine "deck" 140 feet below, paralliding the connecting shafts. No draft tubes are used on the other side of the water-wheels, the water, after leaving them, simply dropping to the bottom of the wheel-pit, where a short, curved passage conducts it to the exit tunnel, and it flows at the rate of about 20 miles per hour to the river below.
It is imperative for the proper operation of an electrical transmission system that the current be at all times kept at the same potential or pressure. The two principal means by which this result is obtained is by keeping the speed of the dynamos constant and by changingthe magnetic in-tensity of their fields, the latter being used to coun-teract the effect of the electrical reactions which take place where the current output is increased and which tend to reduce the potential. The careful regulation of the speed is therefore of great im-portance, and governors which control the revolu-tions of the Niagara turbines are striking examples of mechanical ingenuity. The operation of these speed-governors is extremely accurate, and the immense machines are run with almost clocklike precision. When it is desired to stop a turbine entirely, the regulating gates are insufficient to stop the flow of water, besides having the further disadvantage of being at the bottom of the pen-stocks and leaving them full of water when the wheels are not running. A head gate is, there-fore, placed at the top of the tube which cuts off the water directly at the canal. The frictional resistance to the motion of these gates is greatly reduced by the introduction of rollers, so that one man can open them by manual labor alone.
The type of hydraulic-power development adopted at Niagara, wherein vertical instead of horizontal shafts connected the generators and turbines, necessitated radical changes in the de-sign of the generators. The requirements laid down by the construction company contained many severe conditions, guaranteeing the efficiency of the maker who could satisfactorily com-ply therewith, and the results have shown the wisdom of the company's action. The electrical engineers rose to the occasion and developed a type of dynamo which could be made in the large-sized units specified and yet fulfill the requirements. The ten machines are of 5,000 horse-power each, the 430 cubic feet of water rushing through the turbines below every second turning them at the rate of 250 revolutions per minute. In the early types of dynamos and in those still used for direct current generation the field magnets are stationary and the armature re-volves within them on a horizontal shaft. A similar arrangement might have been used with the vertical shaft employed at Niagara, except that for proper regulation a larger fly-wheel effect was desirable on the turbines. The ordinary construction was, therefore, reversed, and the poles and yoke of the field are supported by arms radiating from the top of the shaft and revolved about the stationary armature in the center. The speed of the periphery of this great mass of iron is 9,000 feet per minute, and the weight of the revolving element about forty tons. The ring which forms the yoke, and which with-stands the immense centrifugal force as well as the magnetic torsional strains, is a solid, nickel-steel forging, 11 feet 7 1/8 inches in diameter, made without a weld. The complete height of the dynamo is 11 feet 6 inches.
The energy produced within the ring is so great that it is difficult to provide sufficient current-carrying capacity in the armature winding. The problem of keeping the apparatus as cool as good practice requires has been solved by the introduction within the armature frame of vertical water-cooling passages. With machines of large dimensions, the power-producing capacity increases much more rapidly than the heat-radiating surface, so that, although with the cost of obtaining power as cheap as it is at Niagara, high efficiency is not required as a saving of energy. It is necessary that the heat-losses in the windings should be kept down to a minimum. As it is, including the wind-resistance, the loss of power is about 200 horse-power for each machine. It has been stated the protruding bolt-heads which surround the field ring in the older ma-chines installed waste seven or eight horsepower in wind-resistance alone. In the newer machines these are recessed into the yoke.
The manner in which the vast amount of energy being delivered by the generators is controlled and distributed is responsible for much of the installation's reputation as an ideal power-plant. The general scheme of grouping the machines in banks of five, each group regulated from a separate switchboard, was adopted by the designing engineers and has been adhered to throughout the entire construction. That this is a most convincing proof of the deep study given to the original plans is readily appreciated by those who have experienced the trouble incident to handling large units at high voltages. The switches which connect the various machines to the distribution circuits and enable the attendants to make the most complicated combinations in the arrangement of the power-service are operated by means of compressed air controlled by valve handles in groups of two and more on neat pedestals. The switchboard galleries present, therefore, a noticeable lack of the complexity or-dinarily found, and their orderly and simple appearance makes it difficult to realize that here the absolute control of 50,000 horse-power is concentrated. The "bus" bars, which carry the currents and the greater part of the switching ap-paratus, are concealed in chambers immediately beneath the switchboard galleries. The pneumatically controlled switches are seldom opened when there is any current flowing through them, and even then a secondary break is provided of non-arcing metal, so that the circuit is not broken at the jaws, where contact is ordinarily made.
Each machine has a panel on the switching gallery entirely devoted to itself, carrying the indi-cating instruments, field regulating rheostat wheel, and other apparatus necessary to the control of its operation. The operation of starting up a machine to aid those already running is very interesting, and any mistake in its details might cause serious trouble. A speed-indicating instrument, or tachometer, is mounted on each generator, and as the gate at the head of the pen-stock is gradually opened, the speed rapidly comes up to the normal 250 revolutions per minute. The switchboard attendant then connects the field cir-cuit to an auxiliary direct current circuit used for exciting the field coils and "builds up" the voltage, or potential, of the machine until the indicating instruments in both phases show that it is capable of being placed in multiple with its fellows and bear its share of the load. Before it can be thrown in with the others, however, it must be running at exactly the same speed, and its armature coils must be passed by the field poles at exactly the same relative times—that is, it must be in synchronism and in step. The attendant learns when the proper conditions are reached by observing an ingenious instrument called a " synchroscope," which indicates by swinging needles the electrical phase relations of the freshly started machine and those already in service.
The typical power station of a decade ago was a chaos of electric wires which were festooned from the ceiling and crossed and recrossed each other in every direction. In the Niagara plant the wires are conspicuous by their absence, it being impossible to find a trace of this most im-portant part of the installation. Vitrified earthenware ducts are laid in the cement floor, so that instead of being stretched overhead, the connecting cables are passed from the machines to the switchboard and then out to the world safely protected from each other and from disturbing forces.
So far, we have considered only the electricity as it is produced at the generator-a 2,000-volt, two-phase, twenty-five-cycle current. It is safe to say that not even a small fraction of the energy is used in this form; but its production is facilitated by the adoption of this voltage and phase conditions. For transmission to Buffalo and other distant cities 11,000 volts and three phases are employed. The railways use a direct current of 500 volts, and the various manufactories and electro-chemical works which have sprung up run the entire gamut of alternating and direct current demand. The transformation of power-station current is, then, a most important part of the system, and as every transformation necessarily entails a loss of energy, the greatest efforts have been made in the design of the converters to bring their efficiency to the highest possible point. The distribution throughout the Niagara district is done with the untransformed primary current as it comes from the switchboard, the various users having converters at their properties which change it to the desired form. The high-tension, three-phase current is produced in a large transformer house directly across the canal from the generating station, is transmitted to Buffalo, Tonawanda, and Lockport, where it is retransformed back to a lower voltage. For the railway lines the high-tension current is led into sub-stations where static transformers reduce its potential to about 350 volts, and it is passed through rotary converters which deliver a 500-volt direct current to the trolley wires.
One of the largest contractors for Niagara power is the Buffalo General Electric Company, which does a general electrical distribution business in that city, furnishing its customers with the usual four classes of service, viz., constant, high-tension current for arc lighting, sixty-cycle alter-nating current for distant incandescent lighting, 500-volt direct current for motor circuits, and 220-volt, three-wire, direct current for incandes-cent lamps. Another large user in Buffalo is the International Traction Company, which has made extensive preparations for increasing its facilities in order that it can handle the throngs which will crowd its cars during themonths of the Pan-American Exposition.
The successful insulation of the high-tension transmission lines has been one of the greatest difficulties met by the operating engineers. It was decided that at such high pressure insulation on the wire itself was useless, and that the safest and best plan was to employ bare copper-conductors, depending on their supports for proper isolation. Large porcelain insulators are placed on the poles to which the conductors are fastened, and give very fair service, but the line is never free from leakage and constant danger of short circuits.
The users of the property or power of the company are called tenants, and only one, the Niagara Falls Paper Company, avails itself of the water-power directly. A row of factories extends along the river front, northward from the power-house, which are operated by electricity. The Carborundum Company, the Pittsburg Reduction Company, the Union Carbide Company, the Mathieson Alkali Company, and many others here utilize the electrical energy in immense quantities and are able to produce many materials at a price other-wise inipossible.
A second power-house is being built on the opposite side of the canal near the transformer station which, when completed, will double thie capacity of the installation. A large plant is also in operation below the Falls, taking its water-power from the old canal, which supplies the mills in this section. The electric plant is placed much lower than were the older buildings and utilizes nearly the full drop of the water which is brought to it from the canal, in a large pen-stock. Much power will, furthermore, undoubtedly be used be-fore long on the Canadian shore, so that by the cataract's side we are steadily extracting its forces bit by bit and shackling the freedom of its mad plunge. One of the boldest engineering and commercial feats of the past century, the successful development of the water-power of Niagara Falls, was the signal for the utilization of water-powers all over the world. This masterpiece of Nature remains to-day with its beauty and grandeur unmarred, its 8,000,000 horse-power inappreciably affected by the petty thefts of man, and its usefulness enhanced a thousand-fold.