SIRIUS Size S00 auxiliary contactor with 3 NO contacts
The Siemens 3RH1131-1TB00-0KV0 is a SIRIUS auxiliary contactor in the Size S00 frame, carrying three instantaneous normally-open contacts. It switches control signals and pilot loads — think PLC digital outputs driving contactor coils, indicator lamps, or small solenoid valves in a panel. The 45 mm wide body clips onto DIN rail or screws to a mounting plate, and the IP20 front keeps live terminals out of accidental contact during commissioning.
Contact ratings — what the voltage columns mean
The contact ratings follow the voltage you actually switch. At 24 V it carries 10 A; at 110 V it drops to 1 A; at 230 V it handles 6 A; at 400 V it's rated 3 A; at 690 V it's 1 A. These are thermal current limits for the contact set — the 24 V figure (10 A) is the highest because lower voltage arcs are easier to extinguish. For a 24 VDC control transformer feeding a row of contactor coils, that 10 A rating is the one that matters. The 230 V and 400 V columns matter when the auxiliary contacts directly switch small motor loads or heater contactors in a mixed-voltage panel.
Mounting and wiring flexibility
Screw and snap-on mounting means it fits a standard 35 mm DIN rail or a backplate. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the panel layout forces an odd angle. Wiring accepts solid conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or 2x 4 mm² per terminal. That covers most control wiring from 18 AWG to 12 AWG. The varistor surge suppressor is built in across the coil terminals, so you don't need an external flyback diode for DC coils.