The Littelfuse 235P is designed to protect 5-15 hp, 230 V, single-phase pumps from dry-well, dead-head, jammed impellers, rapid-cycle, and overvoltage and undervoltage conditions. A calibration adjustment allows the 235P to be calibrated to your specific pumping applications, 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 (sold separately).
Special considerations for pump cables larger than #10 AWG: In some cases where larger motors are installed with deep-set pumps, pump cables are used that exceed the relay’s terminal size. In these conditions, a short splice of #10 AWG or #12 AWG may be a solution at the control box. Note: All local, state, and national electric codes should be followed when applying this solution.
Features & Benefits:
- Proprietary microcontroller-based circuitry: Constant monitoring of voltage and current for reliable pump protection
- Onboard sensitivity adjustment: User-adjustable sensitivity knob makes the unit more adaptable to varying pumping applications
- Adjustable restart delay: Allows user to select well recovery time delay after a dry-well condition occurs, or to select manual reset
- Built-in IR communications link: When used with the Informer, allows user to see stored faults, run time, and troubleshoot the pump while it’s running
- LED indication: Provides status and diagnostics for troubleshooting
- Flexible reset: Reset can be done through a push button on the relay or remotely with optional 777-MRSW or OL-Reset remote reset kit
