At a given pressure, what decreases the torque output of an air motor as speed increases?

The decrease in torque output of an air motor as speed increases is primarily attributed to friction losses. As an air motor operates, various components such as bearings, seals, and other moving parts experience friction. This friction creates resistance to the motion of the motor, which becomes more significant as the speed increases. At higher speeds, these frictional forces can consume a larger percentage of the available power, leading to a decrease in the torque that is effectively delivered to the load.

In addition to the losses from friction, the relationship between torque and speed is intrinsic to how most motors function; they tend to deliver less torque at higher RPMs due to these resistive forces. Understanding the mechanics behind friction losses is crucial for optimizing the efficiency of air motors and ensuring they operate effectively at desired speeds.