In a squirrel‑cage induction motor, the rotor is composed of which of the following?

• A. The rotor consists of heavy bars or rods connected together at the ends
• B. Winding on the rotor
• C. Permanent magnets embedded in the rotor
• D. Laminated iron with no bars

Answer: (A)

The rotor in a squirrel-cage induction motor is a shorted cage of conducting bars embedded in a laminated iron core, with the ends of the bars joined by end rings to form a closed circuit. This cage is what allows the stator’s rotating magnetic field to induce currents in the bars; the end rings complete the circuit, and the interaction between those rotor currents and the stator field produces torque. There are no windings on the rotor and no permanent magnets embedded in it, which distinguishes this design from wound-rotor or permanent-magnet machines. The laminated structure helps reduce eddy current losses while still providing a solid path for the induced currents.