Publication: Western Electrician
Chicago, IL, United States
Electricity at the World's Fair.
Considerable activity was manifested during the last week in the electrical engineering department at the World's Fair, for the work of tearing up the discontinued lighting and power service has been begun, and is being pushed with as much celerity as circumstances permit. Most of the arc lights which have been used for lighting the roadways and furnishing illumination for the grounds have been removed, and circuits are being taken out where suspension of service renders it possible. Electricity building is cold and deserted, save where some belated exhibitor is packing his apparatus for shipment. The tower of light is now merely a barren shaft, the incandescent lamps having been removed some days ago, and it stands unheeded like a blasted oak stripped of its branches, a mere remembrance of the imposing original.
The task of collecting the buoys which marked in fire the path over the lake from the Van Buren street dock to the fair grounds, and of raising the submarine cable which furnished power for the lamps, was commenced as soon as the service plant was shut down, and has now been completed.
One of the most interesting portions of the grounds was probably the least seen by visitors, and doubtless many who thronged the space in front of the administration building, listening to the band concerts and watching the playing fountains, would have been astonished to learn that under their feet were passageways, through which one could walk from machinery hall to the bridge between electricity building and manufactures building. The construction of these conduits for the service wires of the exposition was closely followed in the WESTERN ELECTRICIAN during the days of preliminary work, and time has proven the excellence of the skill and labor employed.
On this page are presented views of some of the methods used to carry and protect the wires which supplied the current for lighting the grounds and buildings, which furnished the power for running most of the machinery, which made it possible to maintain a reliable and efficient police and fire alarm service, and in countless other ways did its share toward making the fair attractive and the visitors comfortable. The central view shows a portion of the Intramural railway near the buildings occupied by the department of engineers, showing one method of carrying power and lighting wires to different portions of the grounds. The view is taken in the southeastern portion of the grounds, looking west. On special oak cross arms, carrying seven pins and resting on girders, run 31 arc light wires which furnish light to the agricultural, forestry, leather, anthropological, and other adjacent buildings. These wires are conducted from the service plant in machinery hall to the overhead structure, in iron pipes, and there are distributed upon the cross-arms.
Twelve No. 0000 conductors convey the current used for power in the southeastern portion of the grounds. They are held in position by the "butterfly" shaped type of special insulator. At one side run eight fire alarm and police signal service wires, furnishing protection to agricultural building and annex, and the southern portion of the grounds. A telephone cable is also shown in the front of the picture entering a distributing box, when the different wires composing it are scattered throughout this section of the grounds. Another system of wire distribution is illustrated at the left in the cut, the view showing a portion of the subway extending from machinery hall to the bridge between electricity and manufactures buildings. This underground vault is really a double subway. It starts from the service plant and extends to a point near the electricity building, where one section branches off to the bridge. Each section of this double subway is the same in size and appearance, being 6 feet 6 inches square built of 2 inch tarred planking, spiked to 3 by 8 inch timbers set 12 inches apart and rendered fire proof by an inch coating of cement held in position by expanded metal lathing. The subway is lighted by 16 candle power incandescent lamps placed in series across a section of the 500 volt power circuit wires. Bolted to the walls at a distance of every 30 feet are upright cast iron frames with supporting sockets into which five-pin oak cross arms, 2 1/4 by 4 inches, are driven and wedged. Every frame supports twelve cross arms, each holding five locust pins, on which are secured a special form of double petticoated glass insulator, arranged to hold two wires each, similar in design to those used-upon the intramural structure. By this arrangement 120 wires may be placed on each set of cross arms; each arm is two feet in length so that a passage way two feet wide is left between the frames. This subway does not pass under the waterways, but on approaching the bridge is expanded out to a width corresponding to that of the bridge, underneath which the wires pass on twelve ten-pin cross arms, supported on the bridge trusses. The view at the right shows that point in the subway near electricity building where the cables are led to the insulators before emerging into the outside space under the bridge. Here they were exposed to the view of those passing under the bridge in the electric launches and gondolas, and the opening afforded a free access of air that insured good ventilation of the subway at all times.
From the bridge, the wires are led to the portico of manufactures building, underneath which the subway is built in a straight line for the. entire length of the west side of the building, thence to the government building and under the bridge to the fisheries building where it ends. The total length of all sections of the subway is about 7,000 feet and entrances are effected through trap doors in the several buildings to which they are connected and also through 1,500 manholes. For the telephone circuits, the New York Safety Insulated Wire company furnished cable for main distribution. These wires, of No. 14 B. & S. gauge are doubled twisted, made up into cables and covered with a layer of jute and two layers of tape. For the arc light circuits. No. 8 stranded, B. W. G. copper conductor was supplied by the same company. That portion used in the ducts has a lead covered rubber insulation. For the incandescent circuits, the New York Insulated Wire company supplied Grimshaw wire of various sizes that was used in connection with the Westinghouse installation. For the fire alarm and police signal service, 75,000 feet of Okonite, rubber covered and braided No. 14 B. & S. Copper conductor and 75,000 feet of double twisted. No. 14 B. & S conductors, braided in two colors were used. The Safety Wire company also furnished 200,000 feet of each of these wires specified for this system. No. 0000 B. & S. wire was employed upon the newer circuits.
There were few features of the exposition that attracted so much popular attention as the electric fountains. The details of construction have already been explained in these columns, and, by glancing at the illustration in Fig. 2, those who are familiar with the electrical features will readily understand how the beautiful effects were secured. One of these fountains will be seen during the midwinter exposition at San Francisco, the work of removing it having already been begun.
A proposition to buy two of the electric launches which were such a source of pleasure to visitors at the fair, at $1,000 a piece, was referred to a special committee of the West Park commissioners of Chicago at the last meeting.
Some trouble has been experienced by the electrical engineering department from attempts to steal wire and other appliances from the grounds. Last week two young men nearly succeeded in getting away with $200 worth of insulated wire from the Midway Plaisance. They entered Midway by walking down the Illinois Central tracks and jumping the fence. They were provided with credentials from the New York Insulating company, which they had obtained in some mysterious manner, and at once began cutting the wire from some of the poles. A guard became suspicious, and with assistance succeeded in arresting one of the men. A closer watch will be kept hereafter, so that similar attempts to remove wire may be frustrated.