The Siemens 3RT2036-3NB30 is a SIRIUS power contactor in the Size S2 frame, designed for switching motor loads and resistive circuits in industrial control panels. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, which keeps panel integration straightforward — the same rail your other SIRIUS gear and terminal blocks ride on. The coil is rated 20-33 V, with a pickup threshold at 0.8 of rated value. Inrush current peaks at 3 A, so factor that into your 24 VDC supply sizing if you're cycling multiple contactors from the same PSU.
Duty cycle and switching rates
Switching frequency depends on the load type: AC-1 (resistive) allows up to 1,000 1/h, AC-3 (motor starting) 800 1/h, AC-2 (slip-ring motors) 600 1/h, and AC-4 (plugging/inching) 250 1/h. If your application involves frequent reversing or jogging, the AC-4 ceiling is the number that governs contact life — not the AC-3 figure.
Termination and environment
Main contact terminals accept 2x (0.5... 2.5 mm²) solid or stranded — spring-type for the coil, which saves a screwdriver turn during commissioning. Operating temperature range is -25 to +60 °C, storage down to -55 °C. The contactor can be rotated ±180° on a vertical surface and tilted ±22.5° forward/backward, giving flexibility in tight enclosures. Keep 10 mm clearance upwards, downwards, and forwards; 6 mm at the sides. Depth is 130 mm, width 55 mm, height 114 mm — the Size S2 footprint fits standard DIN-rail spacing.