When is a run capacitor typically used in motors?

A run capacitor is predominantly utilized in motors during continuous operation to enhance efficiency and performance. It works by providing a phase shift for the current, which helps in creating a rotating magnetic field. This is particularly important in single-phase induction motors, where the capacitor allows the motor to run smoothly and efficiently once it has started.

In contrast, the other options do not accurately reflect the function of a run capacitor. A run capacitor is not exclusively for startup; rather, it continues to operate throughout the motor’s runtime, making it distinct from capacitors used only for starting a motor. Furthermore, it is not involved solely when the motor is idling or during repair, as its primary role is to support efficient operation while the motor is actively running.