Last updated: 8 September, 2021 11:48
Pike's Peak Co. Power plant, Jul. 1902
-> Can be found at the Internet Archive Site. Link to first page of article.
The Engineering Record
July 19, 1902
(pages 50-52)

I procured the coloring of the images, article used grayish
The Plant of the Pike's Peak Power Co.
By R. M. Jones, Engineer and General Superintendent.
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The Pike's Peak Power Company, whose general offices are at Victor, Colo., was organized in 1899, under the laws of Colorado. The company during that year purchased ranch property, placer claims and reservoir sites on Weet and East Beaver Creeks, in Teller and Fremont Counties; located, developed and patented placer claims along these streams, and at this date owns by patent all of the lands on and along these streams, including reservoir sites, and all water power privileges, over a distance of 1½ miles on Beaver, 7 miles on West Beaver and 3½ miles on East Beaver.

These streams are noted for excessive difference in elevation in short distances, and produce sufficient water to make of them valuable water power properties.

Power Station A, Pike's Peak Power Company.
Power Station A of the Pike's Peak Power Co.

One of the power stations contemplated by the company, completed and in operation during the past year, is known as Station A. It is located on West Beaver, in Fremont County, 2½ miles up the stream from the junction of East and West Beaver. The completion of this station has also accomplished much of the development and actual construction for Stations B and C, in the way of reservoir capacity and pipe line delivery of water, which is especially serviceable to the two lower stations after having been used through Station A.

A description of the completed work follows:

Joint Between Steel Face and Concrete.
Joint Between Steel Face and Concrete.
View of the Dam of the Pike's Peak Power Company During Construction.
View of the Dam of the Pike's Peak Power Company During Construction.

Dam and Reservoir.—The dam and reservoir are 5½ miles east of Victor. Here is located the largest steel-faced, granite backfilled dam on record to date. The structure is 405 feet in length along the cap, 220 feet in length of base, 148 feet in cross section at base and 20 feet in cross-section at cap. The upper slope or steel face is 30 degrees from the vertical, and the lower slope 50 degrees.

The height of the dam from the bed rock to the top of the sixteenth plate, at the level of the spillway, is 70 feet. The spillway is 40 feet wide, cut in granite formation and passes around the northwest end of the dam. The granite backfill against which the steel plate rests, is carefully laid as a dry wall of heavy granite boulders, usually of 20 to 80 cubic feet each, as they are broken from heavy blasting, with loose, fine granite filling the intervening spaces.

The steel face is built of sheets measuring 5x15 feet and ½ inch in thickness for the bottom, which is eight plates in height. Continuing, the plate is reduced in thickness to ⅜ inch and finally at the cap it is ¼ inch in thickness. The entire facing is riveted up with horizontal butt straps, and 4x5x½-inch angle bars placed vertically the entire length of the dam. The 5-inch leg of each pair of angle bars projects into the reservoir and constitutes a standing joint seam, with a 2x⅜-inch iron liner, riveted between the extreme outer points of these angle bars, thus making a thorough expansion joint for each section of 15 feet. The bottom and end connections of the entire sheet are concreted into a deep channel quarried out of the bed rock, and the bottom terminates in two pairs of 5x8-inch angle bars, which are riveted through the plates. The end connections are prepared in exactly the same manner, but are applied vertically. The entire facing is riveted up and calked in the same thorough manner as in boiler practice.

A space of 6 inches was left between the steel plates and smooth surface of the granite 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 enter the reservoir.

The reservoir has a surface area of 130 acres and holds 102,000,000 cubic feet of water.

Wood and Steel Pipe Line.—Water is taken into the wood stave pipe through a "Griglay" 240 feet long, perforated, giving 30 times greater area than the pipe. The connections between the Griglay and also those between the main pipe line and the steel facing of the dam are made by steel angles.

The wood pipe is 23,200 feet long, 30 inches in inside diameter and is of 1½-inch redwood stave, banded with ½-inch steel bands and cast-iron lugs. The bands are spaced along the pipe at all distances between 2¼ and 8 inches on centers, as is necessary for resisting the internal pressure, variations being caused by various inverted syphons along the line, two of which have to withstand a head of 215 feet.

Thirty-Inch Wood Stave Pipe, 23,000 Feet Long.
Thirty-Inch Wood Stave Pipe, 23,000 Feet Long.

This pipe line extends over fearfully rough country, about half of the grade being through original granite formation; many curves are on less than 100 feet radius, and there is one compound curve of 36 feet. The wood pipe passes through the Skaguay tunnel, which is 1,535 feet in length, located 21,000 feet from the dam.

From a point 200 feet below the Skaguay tunnel, where the static pressure reaches 220 feet, the line consists of steel pipe 29 inches in diameter in various thicknesses of plates, ranging from ¼ to ¾ inch, as required to meet the internal pressure with an ample factor of safety. The total length of steel pipe, including the receiver, is 2,900 feet, and it is on an incline averaging 38 per cent.

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 335 feet in length, just above which is a bridge 70 feet in height, both being on 40 per cent, gradient, 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 three-foot railway leading from the Skaguay tunnel to the power house, its grade being 1,163 feet vertical in 3,100 feet horizontal. This road is the only means of access to the power house. The cars are operated by a double-hoisting engine.

The upper terminus of the railroad lies under a vertical ledge 70 feet in height, and all machinery, apparatus and materials of all kinds, were lowered by boom and derrick, taking loads from the wagons at the upper landing and lowering them 70 feet over the ledge to the cars. The loaded cars were lowered by means of the friction brake on a hoist, which was equipped with a ¾-inch steel cable; 1,400 tons of building materials passed down this peculiar railroad.

Station A.—The power house is 38x98 feet in size, with two side wings of 16x48 feet each, and is located on the summit of a granite projection surfaced off true to grade. The building is constructed of brick, with a corrugated steel arch roof covered with concrete, tar and gravel; it has a concrete floor and is absolutely fireproof. It is provided with a 10-ton traveling crane.

The hydraulic apparatus was manufactured by the Pelton Water Wheel Company, of San Francisco. Each unit consists of two steel disk wheels 66 inches in diameter keyed to the same shaft and working in the same wheel house.

The base frames are built up in a box pattern of the same type and general design as the generators, 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 the water wheel and generator shafts is effected by the hub of a 7,000-pound steel cast balance wheel banded with a rolled steel tire band 4 inches in thickness. The wheel is 7 feet in diameter.

The nozzles used to develop the required power under the 1,160 feet of effective head obtained at the station require to have a diameter of only one inch to furnish 236 horsepower, including losses. The nozzles for each unit vary in diameter, one having the capacity of the generator, and the nozzles for the other wheel in the same unit being somewhat reduced.

Each wheel in each unit will furnish power for the full capacity of the generator connected to it. In operation, however, it is customary to install nozzles of such varied diameter or capacity as to enable the load requirements to be met by the use of nozzles under full pressure, and thus avoid more than a slight loss in water due to regulation for low loads. The nozzles are of the deflecting type and work under full pressure at all times, which is the cause of the variation in their diameters.

The regulation is of the Armstrong type, owing to the fact that automatic regulation under the existing conditions could be only a failure. Due care has been taken to extend the apparatus for the actual control and regulation of each unit to a point directly in front of the switchboard panel belonging to that unit.

The receiver runs longitudinally through the building under the steel-concrete floor. The discharge or tail-race water returns directly under the receiver to the south or lower 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 through the station with the accumulation in the stream and conduct the combined waters through a pipe line to a point 200 feet above 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 1,257 feet or 544 pounds pressure per square inch. With the added accumulation of water in the West Beaver branch, 3,500 horse-power will be obtained, and from the East Beaver branch, about 2,000 horse-power, all of which may be developed at Station B.

Interior View of Station A.
Interior View of Station A.

The electrical generators now in operation at Station A are four 400-kilowatt General Electric machines, three phase, thirty cycles, 600 volts, with stationary armatures and rotary fields, making 450 revolutions per minute. Two four-pole exciters have a capacity of 30 kilowatts each while running at 675 revolutions per minute, and furnish current at 70 volts, each giving sufficient exciting current for all four generators while working at full load.

With reference to the efficiency of the water wheels, it may be stated that they were guaranteed to develop 83 per cent, of power on their shafts at full load when the nozzles are in normal position. In considering the efficiency of the water wheels, the General Electric Company's generators were assumed to have a commercial-efficiency of 94 per cent, at full nonconductive load, therefore with every 33,000 foot-pounds of water the water wheels will produce in current one indicated horse-power less 17 per cent, loss in the wheels and 6 per cent, loss in the generators, delivering 78/100 horsepower or 582 watts from the brush-holder terminals of the generators.

These efficiencies have been fulfilled by tests. 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, which measurements are verified by spouting tests by working water through nozzles of known diameters.

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, 62x36 inches in size, with a 28x36-inch sub-base, and is 2 inches in thickness; it has a complete equipment of indicating and recording instruments, switches and regulating apparatus. The main line switches from each machine are operated independently either for power or light. The circuits are arranged so that any or all of the machines may be applied on either circuit.

The transformers are six 250-kilowatt air blast, of the 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 and laid in conduits in the concrete floor.

Since the early operation of this station, it was found necessary to install some thorough system for combined arc and incandescent lighting, which has been fully accomplished by the introduction of two 200-kilowatt compensated three-phase generators, 60 cycles, with their full equipment. These generators have 12 poles and operate at 600 revolutions per minute. Each generator contains its own independent 12-pole exciter, built directly on the revolving field-shaft. These machines are also directly connected to impulse type water wheels.

Transmission and Distribution.—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 pole line. The circuits consist of three No. 4 B. & S. power wires, and the lighting circuits of three No. 6 B. & S. wires, which are ample to deliver 1,600 kilowatts at less than a 5 per cent, energy loss.

These lines are transposed at intervals of ½ mile along the line. The poles also carry for telephone purposes two No. 10 galvanized iron weather-proof wires, transposed each 120 feet. The insulators were furnished by R. Thomas & Sons Company, of East Liverpool, Ohio. They are 5½ inches in diameter, of porcelain, and each is same up of three independent cups. In manufacture they are subjected to a 40,000 volt salt test. The line voltage is 12,600, both on 30 and 60 cycle lines.

The sub-station is a brick, steel and concrete structure, adjoining the Gold Coin ore house in Victor. All transmission circuits enter this building where the current is transformed through nine 50-kilowatt General Electric oil transformers to 115 and 460 volts secondary, for local lighting distribution connected in the Y four-wire system and also for local power work.

There is also a set of three 50-kilowatt oil transformers with 350-volt secondaries, which operate a 120-kilowatt rotary converter, furnishing current for a locomotive in the United Mines transportation tunnel for ore hauling, and also for Bull Hill tunnel haulage. High pressure distributing lines leave the sub-station in various directions after first passing through 20,000-volt oil switches, making each line independent.

These branches run to;

Economic Mill, where about 300 horse-power is delivered,

to Beacon Hill for hoists, power and lights,

to the Deadwood mine where a 100 horse-power air compressor is operated,

and a secondary 460-volt power circuit reaches Independence, Altman and the Wild Horse districts.

Another primary line reaches Cameron and Gillett, after first passing through Goldfield, all for lighting services and distributed in each of these towns through their local transformers connected in delta.

Two additional primary distributing lines reach Anaconda, where independent lighting and power is distributed to the town of Anaconda and the various mines in that vicinity.

These lines also reach Elkton on their way to Anaconda, where lighting is also distributed.

Extensions.—It is the purpose of the company to construct an independent transmission line from Station B to Station A and possibly an independent line to the distributing stations in Victor, including the connections through Station A, thus permitting the use of the entire energy of both stations to work in parallel over either station's lines or to work each station independently, as desired.

It is also proposed that transmission lines will be extended from these stations to other localities within reach. Thus, with two complete pipe lines, pole lines and generating station systems, the most unquestioned reliability may be counted upon. It is also the intention of the company to install a third station on the combined Beaver streams at a point near the mouth of the canyon and approximately 2 miles below Station B, to be known as Station C.

Here the difference in elevation is but 373 feet, but as the volume of water will probably reach 50 second feet, this could develop 2,100 horsepower less losses. The company owns also an excellent reservoir site on East Beaver at 1,700 feet elevation above Station B and but 2½ miles distant, which reservoir may be developed to excellent advantage in the near future.

The securities of the company are all owned by the Woods Investment Company, of Colorado Springs and Victor, of which Warren Woods is president, H. E. Woods vice-president and treasurer and F. M. Woods, secretary and general manager. The power company was organized and the property developed originally by the Woods Investment Company for the purpose of supplying power and light to the milling and mining interests owned and controlled by them in the Cripple Creek mining district, but the work of construction was carried out to much larger magnitude than at first intended, and therefore the company is now supplying current to other properties and doing a large proportion of the lighting in the various towns in the district.

 

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