Siemens Allis-Chalmers OLR1253 Overload Relay

Siemens Allis-Chalmers OLR1253 Overload Relay is a thermal overload device designed to protect large three‑phase motors in industrial electrical systems. It is specified for 100–125 A current and up to 600 V AC, making it suitable for motor circuits in pumps, fans, compressors, and conveyors where the motor current can approach the upper end of its nameplate rating. As part of the Siemens Allis-Chalmers overload-relay family, the OLR1253 is used in conjunction with compatible contactors to provide automatic current-triggered protection and disconnection when an overload condition is detected. Installation requires pairing with the appropriate main contactor and wiring according to the machine’s electrical schematic, with adherence to relevant electrical codes and safety standards.