Induction motor versatility the nature of its applications

I ODAY the induction motor bids fair to bring about another revolution of ideas as regards its use and capabilities. Heretofore, particularly in respect to the squirrel cage motor, it has been confined to rather restricted fields of application. Its starting characteristics and the need of special starting devices were against it. Now, limited-starting-current motors such as those employing double cage rotors are overcoming these starting objections. The use of these “across-the-line” motors has encouraged the idea of throwing standard motors directly on the line as well as the use of induction motors for applications demanding frequent starting or reversing. Formerly the squirrel cage motor was looked upon as one to be applied only for constant speed service; today there are many applications where the operating range covers wide variations in speed.