Final answer:
A motor with copper bars in the rotor is classified as an induction type. Unlike DC motors, which use commutators and brushes, induction motors operate through electromagnetic induction, where the rotor bars induce current to produce torque.
Step-by-step explanation:
A motor that has copper bars in the rotor is classified as an induction type. Induction motors, also known as asynchronous motors, operate on the principle of electromagnetic induction, where the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the magnetic field of the stator windings. Therefore, these motors require conductive rotor bars, typically made of copper or aluminum, to facilitate this process. In contrast, synchronous motors, DC motors, and universal motors have different construction and operating principles. DC motors, for example, utilize a commutator and brushes for current direction, while induction motors do not.
The operation of DC motors is explained by figures such as Figure 11.15, illustrating how these DC motors use brushes and commutators to maintain rotation by switching the current's direction. This feature is not found in induction motors, highlighting the distinctive characteristics between different types of motors. Understanding the basic working principles of motors is essential in identifying them correctly based on their physical and functional attributes, such as the presence of copper bars in the rotor.