What it is and what it does
The Siemens 3RT1036-1BW40 is a SIRIUS power contactor in the S2 frame size, designed for switching motor loads in industrial control panels. It's a three-pole contactor with screw-type terminals for the main current circuit, rated for AC-3 duty at 30 kW on a 500 V supply — that's the motor-switching rating that matters for pump, fan, and conveyor applications. The 41 A AC-4 rating at 400 V covers reversing or inching duty where the contactor makes and breaks stalled-rotor current.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. The 55 mm width and 112 mm height fit a standard panel layout; side-by-side mounting is permitted without derating for most applications. The front panel carries IP20 protection — safe for finger contact inside an enclosure — while the terminal area is IP00, meaning the live parts need enclosure protection. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C.
Wiring and termination
Screw terminals accept a wide wire range: solid conductors from 2x 0.5 to 4 mm², stranded from 2x 0.75 to 25 mm². For the main circuit, the maximum solid or stranded is 2x 16 mm². At 40 °C the minimum permissible conductor size is 16 mm² — relevant when sizing for continuous full-load current. The coil draws 10 A at 24 V rated value, dropping to 0.3 A at 220 V rated value.