What it is and what it does
The Siemens SIRIUS 3RH1344-2AP00-0KA0 is an auxiliary contactor in size S00, carrying four NO instantaneous contacts. It's the signal-routing half of a motor starter or a standalone logic element for control circuits — switching pilot loads, PLC inputs, or indicator lamps up to its rated current. Rated AC-12 at 10 A on 24 V, it handles the resistive control-circuit loads typical of relay coils and electronic inputs. At 230 V the rating drops to 6 A, and at 690 V to 1 A — the voltage derating curve matters if you're switching a 690 V control transformer secondary. Mechanical life is 10 million cycles typical, so it's built for high-duty applications like packaging lines or conveyor interlocks where the contactor cycles every few seconds.
Mounting and integration
Snap-on or screw-mount onto a DIN rail — the 45 mm width and 60 mm height fit the S00 footprint common across the SIRIUS contactor family. Side clearance is 0 mm, so you can gang them tight in a panel without derating for heat buildup. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when you're squeezing it into a crowded gland plate or a swing-frame subpanel. Solid wire from 0.25 to 2.5 mm² fits the screw terminals. Pollution degree 3 means it's rated for industrial environments with conductive dust or occasional condensation — no conformal coating required for most panel builds.
What the ratings mean for your panel
The 10 A AC-12 rating at 24 V is the maximum resistive current per contact. If you're switching inductive loads (contactors, solenoid valves), you'll need to derate — AC-15 or DC-13 ratings are what govern those, and they're lower. For a 24 VDC solenoid bank, stay under 1 A per contact unless you verify the DC switching capacity from the full datasheet. Operating temperature range -25 to +60 °C covers most indoor panel environments. Storage range -55 to +80 °C means it can sit in an unheated warehouse or truck without damage. Shock resistance rated at 10g for 5 ms and 5g for 10 ms — enough for mounting on a machine frame or a vibrating conveyor section without contact bounce.