Siemens 3RU2116-1AC1 SIRIUS Thermal Overload Relay
The Siemens 3RU2116-1AC1 is a SIRIUS-brand thermal overload relay, size S00, designed for motor protection in control panels. Its Class 10 trip characteristic means it will trip within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during a stall or locked-rotor condition without nuisance tripping on normal starting inrush. The relay mounts in any position and uses spring-loaded terminals for the main circuit, accepting 2x (0.5... 2.5 mm²) solid or stranded wire.
Key Ratings and What They Mean for Fit
Rated insulation voltage is 690 V, with AC-3e rated maximum at the same 690 V — this relay is suitable for 400 V, 480 V, 500 V, and 690 V motor circuits. Motor power ratings are given at several voltages: 0.55 kW at 400 V, 0.75 kW at 500 V, and 1.1 kW at 690 V. The integrated auxiliary switch (one N/O + one N/C) carries 2 A at 24 V, 2 A at 230 V, 1 A at 400 V, and 3 A at 120 V — enough to signal a trip to a PLC input or drop out a contactor coil. Power loss per pole is 1.9 W, which matters for thermal buildup in a crowded panel.
Deployment Context
This relay is designed for stand-alone installation — it does not require a separate base or contactor mounting. The 45 mm width and 79 mm depth fit a standard DIN-rail footprint, and the spring-loaded terminals speed wiring in panel builds. Temperature compensation is active from -40 to +60 °C, so the trip curve stays accurate across the operating range of most industrial enclosures.