Residential constant pressure water tank repair case
Customer: Longgang City, Shenzhen city center of a garden district
Name: variable frequency constant pressure water supply tank
Model: the Quartet inverter + MITSUBISHI PLC
Fault reason: the frequency changer fault does not automatically switch the pump
Fault analysis: constant pressure water supply system the district is using variable frequency PID control parameters, through the PID output frequency converter control to automatically adjust the pump motor speed closed-loop pipeline pressure regulation (PID), the automatic water supply system of constant to the set pressure value: the water consumption increases, the frequency increases, the pump speed is accelerated, water supply increases; reduce water consumption, reduce the frequency of pump speed slow down, water supply is reduced, so as to ensure the water supply efficiency requirements of water pressure and water at the same time, to improve the water quality and water supply efficiency. The system adopts a pressure sensor (feedback 4~20mA or 0-10V) detection in pipe network pressure, the pressure sensor signal into the PID converter circuit, PID circuit, sends a quantity to increase or decrease the signal to control the motor speed. If in a certain delay time, the pressure is still insufficient or too large, then through the PLC for power frequency / frequency conversion switch, so that the actual pipe network pressure and set pressure. According to the principle of choice to check the output of the inverter inverter, in the fault is the output, only the signal to the MITSUBISHI PLC control. In the PLC program. That program is a bit long delay time of the test can not change the pump automatic time shortened, PLC is to remove the PLC output relay contact measurement found there are 3 poor contact after the replacement test can automatically convert. Fault repair.
Jia Hong Wei maintenance hotline: 13640994287 075528916839 Shaw