What it is and what it does
The Siemens 3RT2036-3SB30 is a SIRIUS S2 power contactor, part of the SIRIUS modular contactor system. It switches motor and resistive loads in industrial control panels, rated for AC and DC switching with arcing times between 10 and 20 ms.
Key ratings and what they mean for fit
The MTBF of 52 a indicates a mean time between failures of 52 years under typical operating conditions, a strong reliability figure for continuous-duty applications. The contactor mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, with a width of 55 mm and depth of 130 mm, fitting standard panel layouts. The operating temperature range of -25 to +60 °C covers most indoor industrial environments, while storage from -55 to +80 °C allows for unheated warehouses. The coil is rated 21 to 33 V with spring-type terminals, drawing 2 VA at 50 Hz and 60 Hz. The spring-type terminals accept 2x (0.5 to 2.5 mm²) solid or stranded wire, speeding wiring and reducing torque errors compared to screw terminals. Mechanical life is typical 5,000,000 operations, with maximum switching rates of 1,000 cycles per hour at AC-1 (resistive), 800 at AC-3 (motor starting), and 250 at AC-4 (plugging/inching). The AC-3e rate matches AC-3 at 800 cycles per hour. These rates govern how fast the contactor can be cycled without overheating.
Where it is used
This SIRIUS S2 contactor is deployed in motor control centers, conveyor systems, pump panels, and general switching applications. The DIN-rail footprint and screw/snap-on mounting simplify integration into new builds or retrofit panels.