The Siemens SIRIUS 3RH2131-4BB40 is a size S00 auxiliary contactor with three normally open instantaneous contacts, driven by a 24 VDC coil that draws 4 W closing and 4 W holding power. It mounts via screw or snap-on onto 35 mm DIN rail, occupying a 45 mm wide footprint with a depth of 73 mm and height of 57.5 mm — a compact slice for control-panel builders packing auxiliary circuits into tight enclosures.
Switching capacity across voltage classes
The contact ratings are given per voltage, not as a single blanket current. DC switching at 24 V is rated 10 A, at 60 V 4.7 A, at 220 V 1.2 A, and at 600 V 0.26 A. These numbers define the load envelope — a wireman sizing the contactor for a mixed-voltage panel reads the row that matches the circuit voltage, not the highest figure on the table.
These spacing rules govern gland-plate layout and side-by-side density — a panel builder derating for heat or arc flash respects the 6 mm side gap even when rail space is tight.
Mechanical endurance and arcing
Arcing time spans 10 to 15 ms; the maximum switching frequency at AC is 10,000 operations per hour. At DC the minimum on-time is 7 to 13 ms. These timing specs matter for a controls integrator coordinating the contactor with a PLC scan cycle or a safety relay's off-delay.