SIRIUS S0 power contactor with integrated RC suppression
The Siemens 3RT1024-3XG28-0MV0 is a SIRIUS S0-frame power contactor rated for AC-4 duty at 12.5 A on 400 V — the switching category that matters for reversing or plugging motor loads where the contactor makes and breaks stalled-rotor current. The built-in RC surge suppressor across the coil saves panel space and eliminates the separate suppressor selection step; just verify free-wheel diode polarity if you add external suppression downstream.
Mounting and integration
Snaps onto 35 mm DIN rail per EN 50022 or screws directly to a backplate. The S0 footprint — 45 mm wide, 88 mm tall, 140 mm deep — fits standard panel layouts; side-by-side mounting is allowed with no derating gap. Screw-type terminals on the main circuit accept 2x (1 … 2.5 mm²) stranded or solid, up to 2x 10 mm² max. Ambient range of -25 to +60 °C during operation covers most indoor panel environments without forced cooling.
Coordination and protection
For Type 2 coordination (no weld-shorting after a fault), the required upstream fuse is gL/gG 25 A. Pollution degree 3 means it's rated for the conductive-dust and humidity levels typical of industrial control panels — not just clean-room switchgear. The contactor's mechanical life is 10 million operations typical, so it holds up on frequent cycling applications like conveyor diverters or reversing stations.