What it is and what it does
The Siemens SIRIUS 3RU2116-1CB0-ZW97 is a size S00 thermal overload relay designed for motor protection in control panels. It mounts directly onto a contactor and provides Class 10 tripping, meaning it will trip within 10 seconds at 7.2× the set current — the standard for protecting standard induction motors during start-up. The relay uses a thermal bimetallic release mechanism to sense motor current and protect against overload conditions. An integrated auxiliary switch provides a "Tripped" signal, rated for switching at various control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. It is rated for main circuit voltages up to 690 V and can protect motors up to 0.75 kW at 400 V, 1.1 kW at 500 V, and 1.5 kW at 690 V. The relay is temperature-compensated across -40 to +60 °C, ensuring consistent trip performance regardless of ambient conditions in the enclosure.
Mounting and integration
This overload relay is designed for direct contactor mounting — it snaps onto the bottom of a SIRIUS contactor without additional hardware. The mounting position is unrestricted, so it can be installed horizontally, vertically, or flat in the panel. Dimensions are 45 mm wide, 76 mm high, and 70 mm deep — a compact footprint that fits standard DIN-rail layouts when paired with its contactor. Main circuit connections use screw-type terminals accepting 2× (0.5 to 1.5 mm²) or 2× (0.75 to 2.5 mm²) solid or stranded wire. The auxiliary contact is integrated into the relay body, so no separate block is needed for the trip signal. Terminal screws require a Pozidriv PZ2 tip with a 5–6 mm shaft diameter.
Lifecycle and sourcing
The relay carries a substance prohibition compliance date of October 1, 2009, indicating it meets RoHS and similar material restrictions. MTTF is listed at 2,280 years under high-demand rate operation, reflecting the reliability expected in continuous-duty industrial applications.