The Littelfuse® 235P is designed to protect 5 to 15 hp, 230 VAC, 1-phase pumps from dry well, dead head, jammed impeller and overvoltage and undervoltage conditions. A calibration adjustment allows the 235P to be calibrated to your specific pumping applications, thereby reducing the possibility of false or nuisance tripping. A unique microcontroller based voltage and current sensing circuit constantly monitors the incoming power for fluctuations causing overcurrent and undercurrent. When an abnormality, such as loss of suction is detected, the 235P deactivates its output relay and directly disconnects the pump motor. The 235P communicates with a hand held diagnostics tool called the informer (sold separately). The informer displays parameters including calibration points, trip points, run time and last faults. An external current transformer is required for operation.