Why don't single-phase induction motors require brushes?

Single-phase induction motors operate on the principle of electromagnetic induction, which is fundamental to their functionality. In these motors, the rotating magnetic field is created through alternating current (AC), which induces current in the rotor, resulting in motion. This process relies entirely on electromagnetic principles without the need for physical contact points that brushes provide in other types of motors.

The absence of brushes means that these motors can operate with less maintenance, as brushes typically wear out over time and require replacement. In contrast, the design of single-phase induction motors allows them to function smoothly without the mechanical components that would necessitate brushes. This contributes to their reliability and longevity.

While other motor types, such as those using direct current, do require brushes due to their specific engineering needs, single-phase induction motors are built to utilize AC and its magnetic characteristics effectively. Thus, the design eliminates the need for brushes altogether, simplifying their construction and operation.