Q. What is Induction machines?
We shall first consider polyphase induction motors and then single-phase induction motors. The polyphase induction motors used in industrial applications are almost without exception three- phase. The stator winding is connected to the ac source, and the rotor winding is either short- circuited, as in squirrel-cage machines, or closed through external resistances, as in wound-rotor machines. The cage machines are also known as brushless machines; the wound-rotor machines are also called slip-ring machines.