In a squirrel-cage induction motor, how are the conductor bars in the rotor core insulated?

In a squirrel-cage induction motor, the conductor bars in the rotor core are not insulated from the core itself. This means that the rotor bars are directly connected to the iron core, allowing for efficient electromagnetic interaction between the rotor and the stator’s magnetic field.

This design is essential for the functioning of the motor because it enables the bars to effectively carry induced currents, which generate the rotor’s magnetic field necessary for torque production. Additionally, the close coupling between the rotor bars and the core helps in minimizing resistance and enhancing the performance of the motor.

The absence of insulation in this case is intentional, as insulating the rotor bars from the core would hinder the performance by introducing additional resistance and reducing the efficiency of the induced currents. This design choice is a fundamental characteristic of squirrel-cage induction motors, contributing to their simplicity, robustness, and efficiency.