Multispeed induction motors

Author(s): H. G. Reist ; H. Maxwell
Publisher: IEEE - Institute of Electrical and Electronics Engineers, Inc.
Publication Date: 1 July 1909
Volume: 28
Page(s): 971 - 979
ISSN (Paper): 0097-2444
DOI: 10.1109/PAIEE.1909.6660054



The induction motor, as generally used, has a speed which varies slightly with the load but which is usually spoken of as being constant. For work where variable speed is required, a motor with collector rings is used, the speed variation being produced by varying the amount of resistance inserted in the secondary circuit. Such a motor is wasteful of power whenever resistance is used, and the speed varies greatly with the load when much reduction in speed is required.