TABLE OF CONTENTS In induction machines, the rotor voltage (which produces the rotor current and the rotor magnetic field) is not physically connected by wires to the rotor windings it is induced in the rotor. The main advantage of induction motors is that there is no need for dc field current to run the machine. An induction machine can be used as a motor or a generator. However, it has many disadvantages as a generator.
Figure 6.1 illustrates a typical two-pole stator for an induction motor. The two main types of rotors are squirrel-cage and wound rotors. Figures 6.2 and 6.3 illustrate squirrel-cage induction motor rotors.
The rotor consists of a series of conducting bars installed into slots carved in the face in the rotor. These bars are shorted at both ends by shorting rings. This design is known as a squirrel-cage rotor. The second type is known as a wound rotor. A wound rotor (Figs. 6.4 and 6.5) has three phase windings that are...
