| Popis: |
Recent advance in the design and application of motors for use with pumps merits the attention of all connected with water and sewerage systems. I assume that all of you are familiar with the direct current constant and varying or adjustable speed motors for driving reciprocating and centrifugal pumps. Also you are no doubt acquainted with the common squirrel cage induction motor for constant speed drive and the slip ring induction motor for either constant or varying speed drive. However, it is doubtful if many realize the possibilities of the synchronous motor for constant speed drive or know anything about the brush shifting polyphase motor for varying speed drive. These types of motors offer advantages that should receive your consideration. While the induction motor has been and still is a very satisfactory motor for pump drive, it has one bad feature, that is, low power factor. This ?neans extra losses incurred by transmitting the excitation to the load and extra investment in larger generators, transformers, and power lines to carry the excitation. Many of the power supply companies are now insisting that the power factor must be a certain amount and the power bill is increased if the power factor |
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