CDPH Water Distribution Grade 2 Practice Test

Monitoring the speed of a variable speed pump is crucial primarily to prevent cavitation from occurring. Cavitation refers to the formation and collapse of vapor bubbles in a fluid, which can lead to severe damage to the pump impeller and other components. When the pump operates at a speed that causes the pressure within the pump to drop below the vapor pressure of the liquid, vapor bubbles form. As these bubbles travel towards higher pressure areas within the pump, they collapse, creating shock waves that can erode surfaces and compromise the integrity of the pump.

Maintaining an appropriate pump speed ensures that the pressure remains suitable for the specific fluid being pumped, thereby reducing the risk of vapor bubble formation. This is particularly important in systems where the fluid viscosity or temperature can change; adjusting the pump speed accordingly helps maintain optimal conditions for operation.

While other factors such as temperature, vibration, and speed oscillation are important aspects of pump operation, the prevention of cavitation is directly related to the control of the pump speed, making it a critical monitoring element in water distribution systems.