Siemens 3RU2136-4BD0 Thermal Overload Relay

Siemens 3RU2136-4BD0 is a three-pole thermal overload relay from the SIRIUS 3RU2 motor-protection family, designed to protect a three-phase motor in low-voltage installations by tripping on overload within the 14–20 A main-circuit range. Sized for installation with Siemens 3RU2 contactors (Size S2), it uses screw terminals for the main circuit and for the auxiliary circuit, and offers a Manual-Automatic-Reset option for how the device recovers after a trip. This relay is intended for motor protection in industrial panels and is commonly used with conveyors, pumps, fans, and other general-purpose motors in protected motor circuits. The 3RU2136-4BD0 variant is one of several 3RU2 models that share core construction and mounting with the same family, distinguished by its 14–20 A setting and the corresponding terminal configuration, enabling straightforward integration into existing Siemens control architectures.