The Siemens SIRIUS 3RH1911-1HA12 is a 4-pole auxiliary switch block with 1 normally open and 2 normally closed contacts, designed for snap-on mounting onto contactor relays and power contactors in the SIRIUS family. Rated for a maximum of 10 A, the switching current varies significantly with voltage: 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, 6 A at 250 V, 3 A at 400 V, and 0.3 A at 220 V. At AC-15 duty up to 690 V it is rated at 1 A. The block uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16) and 2x (18 to 14) AWG for auxiliary circuits.
The 10 A maximum rating governs the resistive load curve; the voltage-specific ratings (6 A at 24 V, 3 A at 400 V, etc.) define the inductive switching capability at each control voltage level. For a 24 VDC control circuit, the 6 A rating is the one that determines whether this block handles the inrush of downstream contactor coils.
Dimensions are 36.5 mm wide, 41.5 mm deep, and 37.5 mm high — a compact footprint that fits standard SIRIUS contactor relay envelopes without consuming additional DIN rail space.