Questions about variable-frequency water supply
Thread Content
I know the basic principle of variable-frequency water supply, but I have a few questions: 1) Can a frequency converter directly control the water pump to achieve simple variable-frequency water supply? But how is its pressure setting done? 2) When using a PLC to control multiple water pumps for constant-pressure water supply, when the water consumption is low or even zero, it is appropriate to reduce the speed of the pumps. However, reducing the speed lowers the pumping capacity of the pumps; could this lead to backflow of water? Generally, check valves are installed in such systems. If the check valve closes, then the motor should stop running, right? I’m not very knowledgeable; could some expert please help me understand this? Thank you!
First, regarding the pressure setting issue, you can refer to the manual; it usually contains relevant information. Most modern frequency converters have PI control functionality, and by connecting an external remote pressure gauge to the frequency converter, the pressure setting can be adjusted using the built-in parameters. Secondly, since it is a constant-pressure water supply system, when the water consumption decreases, the motor speed drops. However, the pressure at the pump outlet must remain constant; therefore, once the pump speed reaches its equilibrium point, it will not drop any further, and water will not flow back