In what situation would a permanent split capacitor motor typically underperform?

A permanent split capacitor (PSC) motor is known for its ability to run efficiently at various speeds and is often used in applications that don't require high starting torque. The design of this motor includes a capacitor that helps to create a phase shift, allowing for smoother operation and better efficiency. However, when it comes to providing high starting torque, PSC motors tend to underperform because the capacitor is used only during the start-up phase of the motor and is not designed to provide the levels of torque required for high-load applications.

In applications requiring high starting torque, alternatives such as split-phase motors or capacitor-start motors are typically preferred, as they can deliver the necessary torque to get the motor moving under heavy loads. This fundamental limitation is why a PSC motor would struggle in situations where high starting torque is essential, making it the correct answer for the question.

The other situations listed do not typically present challenges for PSC motors. They can handle low-speed operations, are often suitable for continuous duty applications, and can even function with soft starters, but their design inherently limits their performance for high-torque applications.