Allen-Bradley 817S-PTC-48 Thermistor Monitoring Relay

The Allen-Bradley 817S-PTC-48 Thermistor Monitoring Relay is a DIN-rail mounted, single-phase protection device that monitors a motor’s thermistor input (PTC) to detect overheating and trips its SPDT output when a fault is detected. It operates on 24- to 48-volt AC or DC control power, making it compatible with many motor-control circuits. As part of the 817S Thermistor Relay family, this unit provides supplemental motor protection functions that can be added to existing circuits to guard against thermal overload and to signal or shut down the motor on temperature events. The SPDT output simplifies integration with starters or controllers for straightforward fault signaling and control.