RMO Real Engineer Practice Exam

Increasing the speed of the motor is the most effective method to enhance the pressure output of a centrifugal compressor. This is because centrifugal compressors operate on the principle of increasing the kinetic energy of the gas, which is then converted into pressure. By driving the compressor at a higher speed, the centrifugal force acting on the gas increases, resulting in a greater velocity and subsequently higher pressure at the discharge. This speed increase directly correlates with the performance characteristics of the compressor, allowing it to handle higher pressure ratios effectively.

When assessing the other options, simply enlarging the size of the compressor may not yield the same immediate increase in pressure, as it primarily affects the volume flow rate rather than the discharge pressure. Reducing the refrigerant load can lower the overall system pressure, which is counterproductive if the goal is to increase pressure. Lastly, increasing the inlet temperature often results in a lower density of the gas, which can reduce the overall efficiency and pressure delivered by the compressor. Thus, enhancing the motor speed stands out as the most reliable approach to achieving higher pressure in a centrifugal compressor setup.