Integrator's note on the 3RT1036-1BD44
The Siemens 3RT1036-1BD44 is a SIRIUS power contactor in size S2, designed for screw-type main circuit connections and snap-on mounting onto 35 mm DIN rail per EN 50022. It carries a 30 kW motor rating at 500 V in AC-3 duty, with a mechanical life of 10 million operations typical. The front face is IP20; the terminal area is IP00, so panel builders should plan for finger-safe shrouding or clearance around the wiring zone.
What the ratings mean for fit
The AC-3 rating of 30 kW at 500 V is the figure that governs motor switching for standard squirrel-cage induction motors — that is the load a panel designer sizes against. At 400 V AC-3 the contactor is rated for 22 kW, and at 690 V it drops to 11.4 kW, reflecting the current derate at higher voltage. The AC-4 rating of 41 A at 400 V covers inching and plugging duty where the contactor makes and breaks stalled-rotor current; the maximum mechanical switching rate of 800 operations per hour in AC-3 sets the thermal cycle limit for repetitive conveyor or pump starts. The coil circuit is rated for 24 V DC at 10 A, 60 V DC at 2 A, 110 V DC at 1 A, and 220 V DC at 0.3 A — these are the contact ratings for the auxiliary contacts, not the main poles. The arcing time of 10 to 15 ms at DC and 20 to 25 ms at DC indicates the interval the arc extinguishes after the coil drops out; this matters for coordinating with downstream fast-acting semiconductor protection. Pollution degree 3 means the contactor is rated for industrial environments where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation may occur — typical for an unsealed panel in a factory floor setting. The operating temperature range of -25 to +60 °C covers most indoor industrial enclosures without active cooling, and storage from -55 to +80 °C allows for warehouse extremes.
Panel integration and wiring
The 3RT1036-1BD44 occupies a 55 mm wide footprint on the DIN rail, with a depth of 179 mm and height of 112 mm. Side-by-side mounting is permitted, so multiple contactors can be ganged without spacing gaps — useful for compact motor control centers. The screw-type terminals accept solid conductors up to 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) for control wiring, and stranded conductors up to 2x (0.75 to 25 mm²) for the main circuit. At 40 °C ambient, the minimum permissible cross-section is 16 mm² for the main power path.