Analyze the reasons for the water pump tripping
Thread Content
Since the unit was put into operation, the water pump has been experiencing the problem of tripping immediately after being switched on after operating for a while. After ruling out faults in the switching mechanism, the cables, secondary circuit wiring, as well as all relays and their setting values were checked using conventional methods, and they were found to be normal; restarting the system then often succeeded. It was later suspected that it was caused by a software fault in the DCS system, but the same issue occurred even when operating from the control panel. Generally, the main reasons for a water pump to trip are as follows: (1) The head under which the pump operates is too low, resulting in excessive flow and an increase in current that exceeds the allowable level. To address this, the opening of the outlet valve can be reduced to control the flow rate and bring the current back within the acceptable range, or the diameter of the impeller can be decreased to lower the pump’s head. (2) Excessive current is caused by the water pump motor getting damp. (3) Quality issues with the water pump motor. (4) The voltage of the water pump is unstable. (5) Issues with the water pump control cabinet system.
At the beginning of pump startup, the current is 2-3 times the rated current. It trips easily. The specific reason can be seen from the water pump performance curve; at startup, the head is 0 and the flow rate is high. On the P–Q curve, the value of P is high, which results in a higher current level. To solve this issue, 1. Install an inverter to delay startup, 2. Open the inlet valve for water, and after the pump starts, slowly open the outlet valve.