What it is and what it does
The Siemens 3RT1024-1BD40-1AA0 is a SIRIUS S0-frame power contactor, screw-terminated, designed for switching motor loads in industrial control panels. It carries a 7.5 kW motor rating at both 400 V and 690 V AC-3 duty, so it handles standard 400 V three-phase motors up to that power and also works at 690 V without derating the power rating — useful on 690 V line supplies common in mining or heavy industry. For reversing or plugging duty (AC-4), the contactor is rated 12.5 A at 400 V, which is the current it can interrupt under those higher-stress switching conditions. The S0 frame keeps the width to 45 mm, and the 85 mm height and 101 mm depth fit standard 35 mm DIN rail enclosures with side-by-side mounting permitted without derating.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022. Side-by-side mounting is allowed, with a 6 mm clearance specified at the side — no extra air gap needed between adjacent contactors of the same frame. The front face carries IP20 finger protection; the terminal area is IP00, so gland-plate clearance and live-part guarding are the panel builder's responsibility. Main circuit terminals accept solid/stranded copper: 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), max 2x 10 mm², with AWG equivalents 2x (16 to 12), 2x (14 to 10), 1x 8. Auxiliary contact terminals are smaller: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Strip lengths follow standard screw-terminal practice — no special tooling needed.
Coordination and protection
For Type 1 coordination (no damage to the contactor, but it may need replacement after a fault), use a gL/gG fuse rated 63 A. For Type 2 coordination (contactor remains operable after a fault), the fuse drops to 25 A gL/gG. These are the manufacturer's specified maximums — the actual fuse size depends on the upstream breaker and cable rating, but these values set the coordination boundary. The contactor is rated for pollution degree 3 (industrial environment with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation). Operating temperature range is -25 to +60 °C, and maximum operating altitude is 2000 m without derating.
Coil and auxiliary ratings
The magnet coil draws 5.4 W both for closing and holding (DC), so the coil power supply sees a constant load once picked up. Auxiliary contact switching capacity is rated at various voltages: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — these are the maximums for the built-in auxiliary contacts, not the main poles. Mechanical endurance is rated at 10 million operating cycles typical for the contactor, which is standard for the S0 frame in cyclic applications like conveyor or pump control.