Millwright Level 3 Practice Test 2025 – Complete Exam Prep

Displacement inside a hydraulic motor is measured in cubic inches per revolution. This measurement indicates the volume of hydraulic fluid that the motor displaces with each full rotation. Understanding the displacement is crucial for determining the motor's performance characteristics, such as its torque and speed capabilities.

When assessing the efficiency and power of a hydraulic motor, knowing how much fluid is moved per revolution allows engineers and technicians to match the motor's specifications with the requirements of the application. This is particularly important in hydraulic systems, where precise control over movement and force is essential.

Other units like gallons per minute (GPM), cubic inches per minute, and gallons per revolution (GPR) relate to different aspects of hydraulic systems, such as flow rate or volume over time, but they do not directly reflect the specific volume displaced with each rotation of the motor. Therefore, cubic inches per revolution provides the most direct measurement of a hydraulic motor's displacement, making it the correct choice.