In December 2003, Shanghai Fujita Brewing Co., Ltd. transformed the production water system into a variable frequency and constant pressure water supply method. The whole system is equipped with one set of constant voltage frequency conversion electrical control cabinet, which controls three sets of water pump motors. The electrical control of the system adopts variable frequency and constant voltage mode. When the system is working, the pressure sensor detects the change of the water consumption of the system, sends the pressure signal to the frequency conversion control system, and automatically adjusts the working state of the motor and water pump after program processing, so that the system pressure is always maintained in a certain pressure range. Thereby improving the water supply environment and improving the energy-saving effect.

  The constant voltage frequency conversion control electrical system adopts Danfoss inverter from Denmark, LG/PLC programmable controller from South Korea and LG low-voltage electrical appliances. It has the characteristics of manual/automatic switching, slope start, energy-saving operation, constant water pressure, no need to be on duty, and automatic rotation of water pumps. The constant voltage variable frequency control device has protection functions such as short circuit, over current, over voltage, and overload. When the system fails, it can automatically stop working and alarm output: the system has functions such as self-check, fault judgment, fault memory, fault display, automatic start-up backup, overpressure and underpressure alarm, set pressure and actual pressure display.