Siemens 3RU2126-1HB0 IEC Thermal Overload Relay

Siemens 3RU2126-1HB0 IEC Thermal Overload Relay is a three‑pole motor protection device designed for mounting on Siemens 3RT2 size S0 contactors. It provides overload protection in a 5.5–8.0 A setting range, class 10, enabling precise matching to a motor’s nameplate current. The relay integrates with screw terminal wiring for both the main circuit and the auxiliary circuit and supports manual, automatic, and reset operating modes for flexible control logic. Built for industrial duty, it withstands shocks up to 8 g for 11 ms and is rated for insulation up to 690 V with a 6 kV surge resistance, enabling reliable operation in demanding environments. Operable across a wide ambient range, the device is specified for temperatures from -40 °C to 70 °C, incorporating temperature compensation to maintain accurate protection as conditions change. As part of the SIRIUS 3RU2 family, the 3RU2126-1HB0 is commonly paired with size‑S0 contactors to protect pumps, fans, conveyors, and other three‑phase motors from overload conditions, while allowing straightforward replacement and integration within existing Siemens control systems.