BY J W. DICKERSON.
NO installation in the Rocky Mountain region where so much capital is now being expended in noteworthy plants is of greater interest than the wonderful power transmission system of the Pike's Peak Power company of Victor, Colo.
This great and splendid enterprise was promoted by the Woods Investment company of Victor and Colorado Springs, at whose head stand Warren Woods, president, F. M. Woods, secretary and treasurer, and H. E. Woods, manager.
The industry and enterprise of these gentlemen have contributed a preponderating share in the development of that wonderful gold producing country during the last few years. By the consolidated companies represented by the Woods Investment company, there are now employed approximately a thousand men.
The Messrs. Woods have been greatly prospered in their activity in the gold camp, and they have shown a striking genius for big deals. They have believed confidently in the future of the famous camp, and their profits have gone back into improvements which have enhanced its prosperity.
This last enterprise will prove of great interest to every engineer, and the brilliant way in which the tremendous obstacles have been overcome will appeal to the imagination of the layman.
The engineer in charge of the work is Mr. R. M. Jones of Salt Lake City, a gentleman of marked engineering ability and fertility of resource, who has been identified with many of the most noted electrical plants since the early days. Many will remember his name particularly in connection with the big Cottonwood Plant, that splendid transmission system in Utah.
The officers of the Pike's Peak Power company are: President, Warren Woods secretary, F. M. Woods treasurer, H. E. Woods engineer, R. M. Jones.
CONSTRUCTION OF DAM.
This company having a capital stock of $1,000,000 has purchased, located and acquired the necessary lands near the confluence of the Beaver Creeks, ranging from seven to twelve miles from Cripple Creek and Victor, Colorado.
Here is being located what is said to be the largest steel-faced granite back-filled dam in the United States. This structure is in length 375 feet across the cap. Along the base the length is 210 feet. Across the cap the cross section is 16 feet, and across the greater part of the base, 138 feet, with a slope of one to one. On the lower slope, and 30 degrees from the vertical, is the upper slope being the space which the steel plate occupies.
Laid up with careful preparation are blocks on the upper and lower surfaces, with loose granite filling in the intervening space. The steel plate is built up of sheets 5 by 15 feet and 0.5 inch in thickness for the bottom, 8 plates in height. Continuing the plate is reduced in thickness to 0.375 of an inch, and finally at the cap, it is 0.25 of an inch in thickness.
The entire sheet is riveted up with horizontal butt straps, and 4 by 5 by 0.5 inch angle bars placed vertically the entire height of the dam across each interval of 15 feet for the entire length of the dam. The five inch leg of each pair of angle bars projects into the reservoir and constitutes a standing joint seam, with an iron liner 0.375 by 2 inches, riveted between the extreme outer points of these angle bars, thus making a thorough expansion joint and providing that expansion and contraction may be taken up within each section of 15 feet.
The bottom end connection of the entire sheet is concreted into a deep channel-way, quarried out of the bed rock, and the bottom terminates in two pairs of 5 by 8 inch angle bars, which are riveted through the plates.
The end connections are prepared in exactly the same manner, but are applied vertically. The quarrying of the bed rock channels was carried out horizontally in each case to a point rising to an elevation, and thence the raise was made abruptly in terrace form.
The entire sheet is riveted up and calked in the same thorough manner as in boiler practice. A space of two inches was left between the steel plates and smooth surface of the granite wall for backfill. This narrow space is taken up by, sand, gravel and sedimentary deposit, the filling being applied with ample water and permitted to dry before water pressure was allowed to be exerted.
PIPE-LINE AND RESERVOIR.
The pipe-line which has been constructed from the dam to within a mile of Station "A" over a distance of twenty-five feet to the north end of the Skaguay Tunnel, and thence through the tunnel 1,400 feet, consists of wood-staved pipe 30 inches in diameter of California redwood, clasped by 0.5 inch steel bands, spaced at such intervals as are necessary for resisting the internal pressure, becoming more frequent where the pressure is increased because of inverted siphons.
Through the tunnel the pipe extends at an elevation producing a gradient of one in 2,400.
From a point 200 feet below the Skaguay tunnel, where the static pressure reaches 270 feet, the line consists of steel pipe 20 inches in diameter in various thicknesses of plates, ranging from 0.1875 to 0.75 of an inch, as required to meet the internal pressure with an ample factor of safety.
The total length of steel pipe, including the receiver, is 8,400 feet, and on an incline averaging 38%. It passes over grades constructed through a tougher granite formation in respect to roughness than ever was encountered in railroad construction in Colorado.
At one point it passes through an inclined tunnel 260 feet in length, just above which is a bridge 70 feet in height, and at various points there are extremely deep open cuts. From the south end of the Skaguay Tunnel the pipe line is entrenched in the grade on which is constructed a narrow gauge railway leading from the tunnel to the power house, and operated on practically a 38% grade.
This road is the only means of access to the power house. The car is operated by a powerful double-hoisting engine.
The upper terminus of the railroad lies under a vertical ledge 70 feet in height, and it is necessary to lower all machinery, apparatus and materials of all kinds by boom and derrick, taking loads from the wagon at the summit and lowering them 70 feet down the ledge to the cars, from which point the load is lowered by friction brake on the hoist, equipped with a 0.75 inch steel cable.
The power house, Station "A." has dimensions 38 by 88 feet, and is located on the summit of a granite projection surfaced off true to grade. The building is constructed of concrete with steel and arched roof, concreted floor, and is absolutely fire-proof.
The hydraulic apparatus is manufactured in accordance with special plans and specifications made by Mr. Jones, the engineer of the Company, and was manufactured by the Pelton Water Wheel company of San Francisco. Each unit consists of two steel disk wheels 66 inches in diameter keyed on the same shaft and working in the same wheel house.
The base frames are built up box pattern of the same type and general design as those water wheels to which they are connected. The frames of the water wheels and generators are faced for accurate, rigid connection to each other by bolts and dowels.
The connection of water wheel and generator shafts is effected by a 6,500 pound steel cast balance wheel, banded with a rolled tire steel band, four inches in thickness. The wheel is seven feet in diameter, and its hub forms the connection on the water wheel shaft and one-half of the hub and face-coupling is keyed to the armature shaft, forming an accurate and rigid connection of the shafts of the two machines.
The nozzles used with which to produce the required power, as applied under 1,160 feet effective head obtained, require only a diameter of one inch to produce energy of 236 horse power including losses. The nozzles for each unit vary in diameter, one having the capacity of the generator, and the corresponding nozzles for the other wheel in the same unit being somewhat reduced.
Each wheel in each unit will produce power for the full capacity of the generator connected. In operation, however, it is proposed to install such a varied diameter or capacity of nozzles as to permit the operation of the full capacity of the load demand from time to time by the operation of nozzles under full pressure, and but slight loss in water due to regulation for low loads.
The nozzles are of the deflecting type, and work under full pressures at all times, which, is the cause of such variation in the diameters of the nozzles. The regulation is of the "Armstrong" type, owing to the belief of the engineer that automatic regulation under existing conditions could be only a failure, without reference to the class applied.
Due care and provision have been taken to extend the actual control and regulation of each unit to a point directly in front of the switchboard panel belonging to that unit. The receiver running longitudinally through the building under an arch constitutes the flooring.
The discharge or tail-race water returns directly under the receiver to the north or upper end of the building at which point it will later unite with water conducted from a point 800 feet above Station "A," where a catcher-dam is to be constructed, and the water diverted from the Beaver stream channel.
There is a considerable accumulation of water between the dam and Station "A," and it is the purpose of the company to unite the waters used through Station "A" with the accumulation in the stream, and conduct the combined waters through a pipe line of larger diameter to a point one-fourth mile below the forks of the east and west Beaver Creek, at which point there will be constructed Station "B."
There will be built a small pipe line up the east Beaver to the same static level as the tail-race water of Station '"A." The waters of both pipe lines will be united before entering the receiver. The pressure of Station "B"' will be also 1,160 feet or 504 pounds pressure per square inch.
With the added accumulation of water obtainable it is believed that 3,500 horse power will be obtained.
The electrical generators will be four 400 kilowatt General Electric machines, three phase, thirty cycles, with stationary armatures and rotary fields, making 450 revolutions per minute. In some respects, the dynamos are different in design from any generators yet manufactured.
As already mentioned, the generators will be driven directly connected to the water wheels. The four-pole exciters, direct current machines, have a capacity of 30 kilowatts each, running at 675 revolutions per minute, producing an exciting current at 70 volts, each having a sufficient exciting current for all four generators, while working at full load.
In reference to the efficiency of the water wheels, it may be stated that they are guaranteed to develop 83% of power on their shafts at full load under conditions when the nozzles are in normal position. In considering the efficiency of the water wheels, the General Electric company's generators are assumed to have a commercial efficiency of 94% at full non-inductive load, therefore with every 33,000 foot pounds of water the water wheels will produce in current one indicated horse power less 17% loss in the wheels and 6% loss in the generators, delivering 78-100 horse power or 582 watts from the brush-holder terminals of the generators.
All water connections are tested to 800 pounds pressure to the square inch. In making the efficiency tests, measurements are made through the standard weir commonly used in the United States. The developed power is measured by the highest grade of electrical instruments obtainable.
The switchboard apparatus is especially liberal in design, and is made up of one exciting current panel, four generator panels, two distributing panels, two high tension panels, and one paralleling or synchronizing panel. Each panel is made of Vermont marble, 62 by 36 inches, with a sub-base 28 by 36 inches, and two inches in thickness, with a complete equipment of indicating and recording instruments, switches and regulating apparatus.
The main line switches from each machine are operated independently cither for power or light. The circuits are arranged so that any or all the machines may be applied on either circuit. The transformers are six 250 kilowatt air blast converters of one General Electric make, having 600 volts on the primaries and 12,600 on the secondaries.
The twelve complete sets of lightning arresters are of the General Electric make. The cable connections between the generators and switchboard and from the switchboard to the transformers are all highly insulated, paper, rubber, lead, and laid in conduits in the concrete floor.
The line transmission from Station "A" to the center of distribution (at the Gold Coin mine at Victor) includes a distance of eight miles by the pole line. The circuits consist of three power wires, No. 4 B. and S. G., and the lighting circuits of three No. 6 B. and S. G. which are ample to deliver 1,600 kilowatts at less than a five per cent energy loss.
The poles will also carry for telephone purposes two No. 10 galvanized iron weather-proof wires. The insulators were furnished by R. Thomas & Sons Company of East Liverpool, Ohio, They are 5.5 inches in diameter of porcelain and each is made up of three independent cups. In manufacture, they are subjected to a 40,000 volt salt test.
The line voltage will be 12,000 or 12,600, the current being generated at the latter figure to compensate for any line loss.
DIFFICULTIES OF LINE CONSTRUCTION.
The line leaving the station passes over a district on which a pole line cannot be constructed, for a distance of 3,400 feet This rough region will be covered by a set of iron wire cable conductors of the same carrying capacity as the copper wire on the pole line.
This distance of 3,400 feet will be covered by four spans, the longest being 1,120 feet. The four available supports are summits of sharp granite ridges, and the depression in one case between the two points of support is in excess of 800 feet.
Heavy frame-work is drift-bolted to the surface of these ridges, containing one eight pin cross-arm, with steel pins for each wire. The cross-arms are placed parallel to the wire for sustaining the great weight of each circuit.
The entire distance covered is one tangent and there is a uniform gradient of 40 per cent.
PLANS FOR EXTENSIONS.
It is the purpose of the company to construct an independent transmission line from Station "B" to the distributing station in Victor including the connection of the line circuits through switchboard connections through Station "A," thus permitting the use of the entire energy of both stations to work in parallel over either station's line or to work each station independently and synchronize at the sub-station, or distribute independently, as desired.
Thus with two complete pipe lines, pole lines and generating station systems, the most unquestioned reliability may be counted upon. The distribution of light and power, together with the company's independent telephone system, will radiate in the customary manner to the various mills and mines operated by the owners of the Pike's Peak Power company, the Woods Investment company, which at the present time, prior to the starting of the station, has nearly a sufficient demand for the entire product to be generated at Station "A."
In reference to the future distribution, just what the policy of the company will be cannot now be stated.