The Siemens 3RT1024-1BB40-ZW95 is a SIRIUS power contactor in the S0 frame size, built for switching motor loads and resistive circuits in industrial control panels. The 24 VDC magnet coil draws 5.4 W on closing and holding, so the control transformer or DC supply needs to deliver that continuously. Screw-type terminals on the main circuit accept up to 2x 10 mm² stranded or 1x 8 AWG — enough for the 10 A AC-12 maximum or the 12.5 A AC-4 at 400 V.
Mounting and panel fit
Snaps onto a 35 mm DIN rail per DIN EN 50022, or can be screw-mounted. The S0 footprint is 45 mm wide, 85 mm tall, 101 mm deep — side-by-side mounting is allowed with a 6 mm gap to the side. IP20 on the front, IP00 at the terminals, so it lives inside a closed panel; not for washdown zones.
Coordination and protection
With type 2 coordination (no welding after a short circuit), the required upstream fuse is gL/gG 25 A. For type 1 (replace after fault), it's 63 A. That's the short-circuit protection sizing; the contactor itself is rated for pollution degree 3, so it handles the conductive dust and humidity typical of a mill or crusher panel without creeping.