What is the function of the air gap in a synchronous motor compared to an induction motor?

The air gap in a synchronous motor can indeed be larger compared to that in an induction motor due to the differing operating principles of these two types of motors. In a synchronous motor, the rotor is locked in synchronism with the rotating magnetic field of the stator, and it requires a specific alignment and magnetic interaction to maintain stable operation.

To accommodate its unique operational characteristics, a synchronous motor can safely operate with a larger air gap without compromising performance, allowing for more flexibility in design and construction. This is in contrast to an induction motor, where a smaller air gap is usually preferred to enhance the magnetic coupling between the stator and rotor, which is essential for its operation based on the principle of electromagnetic induction.

The larger air gap in synchronous motors does not inherently affect the rotor's stability or overheating directly but accommodates the way these motors achieve their magnetic alignment. By allowing this variability, designers can optimize performance for different applications, making it a key factor in understanding motor design and functioning.