The Siemens 3RN2000-1AA30 is a SIRIUS thermistor motor protection relay — a compact evaluation unit designed to monitor motor winding temperature via PTC thermistors (bimetallic switch). It operates on a 24 V AC/DC supply (rated value 24... 24 V at both 50 Hz and 60 Hz) and provides a 1 A output at 24 V for signaling or direct contactor control. Housed in a 17.5 mm wide, 100 mm high, 90 mm deep enclosure, it mounts on 35 mm DIN rail with screw and snap-on fastening. IP20 rated, with screw-type terminals accepting solid or stranded wire from 20 to 12 AWG (1x 20–12, 2x 20–14). The relay features auto-reset (no external reset), an LED display version, and an initial value (response threshold) of 0.85 times the full-scale value of 1.1. Relative metering precision is 9 %. No galvanic isolation between input and output. Pollution degree 3 rated.
The compact 17.5 mm width (one standard module) saves panel space — fits a single slot in a typical terminal-block row. Clearance: 0 mm upwards, downwards, forwards, backwards, and at the side — no mandatory air gaps for this relay, though adjacent heat-generating devices should be considered in dense layouts. Screw-type terminals accept 1x 20–12 AWG solid or 2x 20–14 AWG solid (stranded 20–12 AWG). Strip length and torque follow standard Siemens terminal practice for this class. The design allows jumpering terminal A1 with the root of the changeover contact for bimetallic switch compatibility — see the manual for the exact wiring pattern.
Output Ratings & Application
The relay's output contact is rated 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V. These are the maximum switching currents — use them to size the downstream contactor or PLC input. For typical motor protection duty, the 1 A at 24 V is sufficient to energize a small contactor coil or signal a digital input. No galvanic isolation between input and output means the PTC circuit and the output share a common reference.