Hawkins electrical guide Volume 5; Questions, answers & illustrations a progressive course of study for engineers, electricians, students and those ... and its applications a practical treatise - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ...as sheets held in place by the windings, when no ventilating ducts are provided, or moulded to correct form and held between sheets of tough insulating material where ducts are provided for air or oil circulation. Ques. Describe the "minor" insulation. Ans. It is the insulation placed between adjacent turns of the coils. Since the difference of pressure is small between the adjacent turns the insulation need not be very thick. It usually consists of a double thickness of cotton wrapped around each conductor. For round conductors, the ordinary double covered magnet wire is satisfactory. Ques. What is the most efficient insulating material for transformers? Ans. Mica. FlG. 1,974.--Three Westinghouse 20 kva, outdoor transformers, for irrigation service. These are mounted on a drag so that they may be readily transported from place to place. 33,000 volts high tension; 2,200 and 440 volts low tension, 50 cycles. These outdoor transformers are of the oil immersed, selfgcooling type and have been developed to meet the requirements for transformers of capacities greater or of voltages higher than are usually found in distribution work. They are in reality distributing transformers for high voltage, outdoor installations, single or three phase service, for voltages up to 110,000. Where the magnitude of the load does not warrant an expensive installation, transformers of the outdoor type are particularly applicable. The cost of a building and outlet bushings which is often the item of greatest expense is eliminated where outdoor type transformers are installed. It has a high dielective strength, is fireproof, and is the most desirable insulator where there are no sharp corners. Oil Insulated Transformers.--High voltage transformers are insulated with oil, a...
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