Which is NOT a part of an air motor?

An air motor typically consists of components such as a rotor, shaft, and vane, which play essential roles in its operation. The rotor is responsible for converting airflow into rotational motion, while the shaft transmits that motion to the output. The vane helps in guiding airflow within the motor, ensuring efficient operation.

In this context, a chamber refers to the enclosed space within the air motor where the working fluid (air) is contained and where various motion and pressure interactions occur. While chambers are critical in the design and function of many pneumatic devices, they are not classified as a separate, distinct part like the rotor, shaft, or vane. Therefore, it is accurate to say that "chamber" is not a specific part of an air motor in the same way the other components are identified, making it the correct choice for the question.