What is a notable disadvantage of shaded pole motors?

Shaded pole motors are known for their simple construction and reliability, but one of their notable disadvantages is their low starting torque compared to other types of motors. This characteristic arises from the way shaded pole motors are designed, where the starting mechanism relies on the interaction between the electromagnetic fields created by the multiple shaded poles.

In applications where a higher starting torque is crucial, such as in fans or pumps, the low starting torque of shaded pole motors can be a significant limitation, making them less suitable for tasks requiring immediate power or heavy loads. This is particularly relevant in comparison to other single-phase motor types, such as split-phase or capacitor-start motors, which are designed to provide higher starting torque.

While the other options touch on important aspects of shaded pole motors, they do not define a principal limiting factor as strongly as the low starting torque. For example, while shaded pole motors can produce operational noise, this is not as defining a disadvantage as their inability to start under load effectively. Overheating and energy consumption can also be factors, but they do not outweigh the critical impact of low starting torque in terms of performance in various applications.