SIRIUS Size S0 power contactor — 3RT1024-1AH04
The Siemens 3RT1024-1AH04 is a SIRIUS power contactor in the Size S0 frame, with three normally-open main contacts and no normally-closed main contacts. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022, making it a direct fit for standard industrial control panels. The screw-type main terminals accept 2x (0.5 to 1.5 mm²) solid, 2x (0.75 to 2.5 mm²) stranded, and up to 2x 4 mm² or 1x 10 mm² — covering the common wire sizes for motor circuits in this frame. Rated for AC-3 duty at 7.5 kW on both 500 V and 690 V supplies, this contactor handles three-phase induction motors up to that power class. The AC-4 rating of 12.5 A at 400 V covers reversing or inching applications where the contactor makes and breaks the load under full current. For Type 1 coordination, a 63 A gL/gG fuse protects the contactor; for Type 2 coordination (limited weld risk), the fuse drops to 25 A gL/gG.
Mounting and integration
The 45 mm wide, 85 mm high, 140 mm deep footprint fits the S0 frame standard. Side-by-side mounting is permitted without derating, with a 6 mm clearance required at the side for heat dissipation. The front face carries an IP20 rating (finger-safe), while the terminal area is IP00 — expect exposed live parts at the wiring point. Operating temperature spans -25 to +60 °C, with a maximum altitude of 2,000 m. Pollution degree 3 means it's rated for industrial environments with conductive pollution.
Auxiliary contact ratings
The built-in auxiliary contact block (1 NO + 1 NC) carries a rated operational current of 10 A at AC-12 (resistive loads). For DC switching, the ratings are: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, and 6 A at 230 V AC. The coil operates at 50 Hz with a voltage tolerance of 0.8 to 1.1 times the rated voltage (48 V). Mechanical endurance is rated at 10 million operating cycles typical.