Siemens 3RU2116-1FB0 Thermal Overload Relay

Siemens SIRIUS 3RU2116-1FB0 thermal overload relay delivers current‑dependent motor protection for three‑phase loads, designed to mount directly on size S00 contactors in the 3RU2 family. It offers an adjustable trip range of 3.5–5 A for protection of 3‑pole main circuits, with screw terminals on both the main and auxiliary circuits and a choice of manual or automatic reset. Rated for up to 690 V AC with 690 V insulation, the relay is built for harsh panel environments (ambient operating range −40 to +70 °C) and IP20 protection on the front. In operation, it provides inverse‑time thermal overload protection to prevent motor damage due to overload, phase imbalance, or phase loss, and is specified as a stand‑alone protective device or as an integral part of a Siemens 3RT contactor assembly. Typical power loss at the rated current is about 6.1 W total (roughly 2.2 W per pole), reflecting its compact S00 package while maintaining reliable protection. This model is identified as part of the SIRIUS 3RU2 family, Class 10 accuracy, and is suitable for applications in pumps, fans, conveyors, and other equipment where controlled motor protection and straightforward reset are required.