首先启动1号水泵电机工作在调速状态。当变频器运行频率到达上限时，并稳定

First, start the motor of the No. 1 water pump to work in the state of speed regulation. When the operating frequency of the inverter reaches the upper limit and runs stably, if the pipe network pressure is lower than the set value of water pressure at this time, add No. 2 water pump. Under the logic control of the PLC, the electromagnetic switch connecting the No. 1 pump motor and the inverter is disconnected, the No. 1 pump motor is switched to power frequency operation, and the inverter is connected with the No. 2 pump motor to make the No. 2 pump motor work in speed regulation. status. When the water supply pressure is greater than the set value, it needs to enter the process of reducing the pump. At this time, the output frequency of the inverter decreases, and the speed of the water pump motor decreases. When the output frequency of the inverter reaches the lower limit and runs stably for a period of time, the water pump controlled by the inverter is stopped. If both water pumps are running at this time, reduce the No. 2 water pump, and make the No. 1 water pump motor work in the speed control state. Otherwise, the No. 1 water pump stops. If the pipe network pressure is still greater than the set value, stop.

First start the No. 1 pump motor to work in the speed control state. When the frequency of the drive reaches the upper limit and is stable, if the pipe network pressure is below the water pressure setting at this time, add pump No. 2. Under the logical control of PLC, the electromagnetic switch connecting the No. 1 pump motor to the drive is disconnected, the No. 1 pump motor is switched to the frequency operation, and the inverter is connected to the No. 2 pump motor, so that the No. 2 pump motor is operating in the speed control state. When the water supply pressure is greater than the set value, the pump reduction process is required. At this time, the drive output frequency is reduced, the pump motor speed is reduced, when the output frequency of the drive reaches the lower limit, and stable operation for a period of time, the drive-controlled water pump shut down. If both pumps are operating at this time, subtract pump 2 and put pump 1 motor in the speed control state. Otherwise pump No. 1 shuts down. If the pipe network pressure is still greater than the set value, stop.

Firstly, start the motor of No.1 water pump to work in the speed regulation state. When the frequency of frequency converter reaches the upper limit, and after stable operation, if the pipe network pressure is lower than the set value of water pressure, add No. 2 water pump. Under the logic control of PLC, the electromagnetic switch connecting the No.1 water pump motor and the frequency converter is disconnected, the No.1 water pump motor is switched to the power frequency operation, and the frequency converter is connected with the No.2 water pump motor to make the No.2 water pump motor work in the speed regulation state. When the water supply pressure is greater than the set value, it is necessary to enter the pump reduction process. At this time, the output frequency of the frequency converter decreases, and the speed of the water pump motor decreases. When the output frequency of the frequency converter reaches the lower limit and operates stably for a period of time, the water pump controlled by the frequency converter is stopped. If both pumps are running at this time, reduce No.2 water pump and make No.1 water pump motor work in speed regulation state. Otherwise, No.1 water pump stops. If the pipe network pressure is still greater than the set value, stop the machine.<br>