Maximum Power and Torque
Power in rotational form is the product of both torque and angular speed, and so it follows that no power is required if either of these two terms is zero. Torque, for example, commonly exists without any power being required to sustain it. A weight hanging on a cable wound around a stationary winch drum will twist the drum’s shaft, but as long as no movement occurs, no power is ever needed to hold that weight in place. Rotation too can exist without power if torque is zero, but since friction is always present to impede movement, we never experience constant unpowered rotation. It is only when both torque and angular speed act together that power exists.
The generalized definition of rotational power involves ...