The Siemens SIRIUS 3RH7131-1AB00 is a contactor relay in the S00 frame size, carrying 3 normally-open and 1 normally-closed auxiliary contacts (31 E switching element identification). It is designed for AC control voltage at 24 V, 50/60 Hz, with a rated operating range of 0.8 to 1.1 times the rated voltage at 50 Hz and 0.85 to 1.1 at 60 Hz — meaning the coil pulls in reliably even with a sagging line down to about 19 VAC. Its auxiliary contacts are rated for PLC-level signals — the datasheet certifies contact reliability at 17 V, 5 mA, so it switches low-energy logic loads without the oxidation failures that plague general-purpose relays on dry circuits. Switching capacity varies with voltage: 6 A at 24 VAC, 110 VAC, 230 VAC, and 400 VAC; 1 A at 690 VAC; and 0.3 A at 220 VAC. The surge voltage resistance is 14 kV, giving it solid margin for industrial line transients.
The S00 footprint — 45 mm wide, 57.5 mm tall, 72 mm deep — fits standard control-panel spacing. Connections are screw-type terminals accepting 2 x 0.5 to 1.5 mm² solid or stranded, 2 x 0.75 to 2.5 mm², or 2 x 4 mm². Finely stranded wire with ferrule is also supported in the same ranges.
Coil and performance
The AC magnet coil draws 27 VA inrush (pick-up) and 5.4 VA holding, with inductive power factors of 0.8 and 0.27 respectively. That holding power is low enough to keep thermal rise minimal in a densely packed panel. Rated for 1 000 operations per hour at DC-13 duty, with shock resistance of 15g / 5 ms and 8g / 10 ms for sine pulse, and 10g / 5 ms, 5g / 10 ms for rectangular pulse. Maximum installation altitude is 2 000 m above sea level. The auxiliary switch extension is supported — the product designation includes product extension auxiliary switch capability, meaning add-on blocks can be stacked on this relay.