Posted July 20, 201212 yr A Cleveland Streetcar Substation The Cleveland, Ohio Cedar Avenue substation was constructed in 1917, and was the first automatic substation completed for the Cleveland Railway Company. It was across the street from the Cedar Avenue power plant, which was then at the time the largest non-condensing direct-current plant in the United States, and was operated non-condensing because the exhaust steam was sold to a salt company adjacent at a price that made it difficult for the central station companies in Cleveland to compete with the Cleveland Railway's power house on a per-kilowatt-hour output. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 700. And today. It was later decided that the cost to upgrade the Cedar Avenue power plant was prohibitively expensive. The production value at the Cedar Avenue facility was $1,265,565, and this, deducting the salvage of machinery and equipment estimated at $115,565, could be paid off at a rate of $20,000 per month. The cost of outsourcing electric production to the Cleveland Electric Illuminating Company was less than 6 mills per kilowatt. The cost of energy production in the Cedar Avenue plant was about one cent per kilowatt. The new Cedar Avenue substation featured eight rotaries, each 1,500-kw in capacity with 60-cycle 514-RPM Westinghouse machines. With the installation, the railway company boasted 20 rotaries of 1,500-kilowatt capacity each and two 1,000-kilowatt-capacity, with controlling apparatus sourced from General Electric. The transformers were air-cooled Westinghouse 550-kilovolt-ampere., 11,000/410-volt single-phase units installed without shells. Below is a cross-section of the plant and a layout scheme. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 701-702. Direct-current ends of rotary converters and the front of a main control switchboard. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 703. And after. Alternating-current ends of the rotary converters and rows of control apparatus. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 702. And today. The decision to use smaller capacity rotaries instead of four 3,000-kilowatt units came down to redundancy. If a serious overload was achieved and one of the units was subsequently disabled, an ever greater strain may have been imposed on the remaining units, A load of only 1,500-kilowatt, however, spread over seven units would overload each unit just slightly. There was determined to be little efficiency loss. The exterior was finished with press brick in the front, with cut stone trim, with an interior and side walls of shale brick laid in cement motar. The interior also featured a tile finish. The roof was concrete supported on steel girders. After the exterior was finished, the interior electrical equipment, switchboards and so forth were installed in just five weeks. On June 15, 1948, the Cedar Avenue streetcar line was replaced with a trackless trolley, which was then replaced with buses on April 12, 1963. Below is a photograph of "special switchboards, at right an ammeter board for use in measuring distance tables and at left a house-service board." From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 704. And today. Mounting of feeder cables in substation basement and subway. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 703. And today. Busbar and disconnect switch compartments with lamp indicators. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 701. And today. Rear of alternating-current section of main control board. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 701. And today. Rear of direct-current section of main control board. From "Designing and Operating the Substation for Maximum Efficiency." Electric Railway Journal 51.15 (Apr. 13, 1918): 701. Other views of the streetcar substation include,
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July 21, 201212 yr Interesting photos and historical info. The device below first registered with my brain as a generator, and it wasn't until I was looking at the photo at home after a trip to Pennsylvania that it dawned on me that it's a rotary converter. It's probably smaller than the ones in the Cleveland substation. Rotary converters have both the commutator of a direct-current motor or generator, and the slip rings of an alternating-current motor or generator. A rotary converter may be used to convert AC to DC or DC to AC, or may function as either a motor or a generator, depending upon how it is configured. Before commercial and public electric utilities had widespread distribution systems with industrial capacity, most streetcar and interurban ("traction") systems generated their own electric power. Large systems distributed power over long distances using alternating current because they could use transformers to step up the voltage, reducing line losses. High-capacity solid-state rectifiers and controllers didn't exist then, so at various points along the line, typically every 25 miles or so on interurban lines, rotary converters, or "rotaries," converted the AC power to direct current to maintain the voltage in the catenary (overhead trolley wire) that powered the cars. Traction catenary power typically was 600 volts DC, alhough a few systems used other voltages, either DC or AC.
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