What Is The Control Principle Of The Fully Protected Submersible Sewage Pump

Feb 23, 2026

Fully protected submersible pumps usually include signal detection for overload, leakage, and phase loss protection to prevent pump burnout caused by overcurrent, leakage, and other reasons, which may endanger the normal operation of other equipment and human safety. In order to monitor the operation status of the pump in real time, submersible pumps are usually equipped with these sensors. Below is a brief analysis of the detection principle.

Temperature detection

Due to bearing problems or improper selection, the pump may experience excessive axial force, resulting in damage to the pump bearings or even to the motor. Therefore, temperature sensors are installed at the bearing locations to provide motor protection when the pump experiences overload and the motor winding heats up.

 

 

The temperature sensor adopts a thermistor, which mainly considers the high temperature resistance value of the pump winding and the temperature rise value at full load of the pump. When a sudden situation occurs in the pump, heat is quickly transferred to the protector through the thermal sensor, cutting off the power supply.

Leak detection

When water enters the stator winding of an electric motor due to poor sealing, a detection probe needs to be designed. The detection principle of the leakage probe is to use two electrode probes buried in the submersible pump. Once water enters, the resistance value between the two poles greatly decreases, thus achieving the purpose of signal detection.

Detection of vibration signals

When the blades of a submersible sewage pump are entangled by impurities in the water, causing the impeller of the pump to rotate out of balance, it will cause severe vibration of the pump. A piezoelectric vibration sensor is installed in the pump. The sensor consists of a spring, a mass block piezoelectric plate, and a base. Rigidly fix the sensor base near the bearing between the submersible pump motor and to sense the mechanical vibration of the pump. When the sensor is subjected to vibration, due to the considerable stiffness of the spring and the relatively small mass of the mass block, it can be considered that the inertia of the mass is very small.

 

 

Therefore, the mass block feels the same vibration as the sensor base and is subjected to an inertial force in the opposite direction of acceleration. In this way, the mass block has an alternating force proportional to the acceleration acting on the piezoelectric element. Due to the piezoelectric effect of piezoelectric elements, alternating charges are generated on their two surfaces.