What it is and what it does
The Siemens 3RT1046-3XB40-0LA2 is a SIRIUS power contactor in size S3, designed for switching motor loads in industrial control panels. It is rated for 55 kW at 500 V and 25.4 kW at 690 V under AC-3 duty, meaning it handles the high inrush of induction motors up to those power levels without welding contacts.
Mounting and integration
Mounts via screw or snap-on onto 35 mm or 75 mm standard DIN rail — common in European-style panels. Dimensions are 70 mm wide, 176 mm tall, 152 mm deep, so it fits a standard S3 footprint. Side-by-side mounting is allowed with no derating gap, which saves rail space in dense layouts.
Coil and control circuit
Coil is 24 V DC rated, with a pickup dropout range typical for SIRIUS contactors — holds at 24 V nominal, drops out below 18 V. The DC coil draws 10 A at 24 V rated value, 2 A at 60 V, and 0.3 A at 220 V, so verify your control transformer sizing for the inrush.