down to about 50% rated speed, but efficiency is low. Multispeed AC
Motors. Consequent-pole ac
motors are designed for one speed. By physically reconnecting the leads, a 2:1 speed ratio can be obtained. Typical
synchronous speeds for 60-Hz ac
motors are:
3,600/1,800 rpm (2/4 pole), 1,800/900 rpm (4/8 pole), and 1,200/600 rpm (6/12 pole). Two-winding ac
motors have two separate windings that can be wound for any number of poles so that other speed ratios can be obtained. However, ratios greater...
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