SIRIUS S0 power contactor with 48 VDC coil
The Siemens 3RT2025-2BW40 is a SIRIUS-brand power contactor in the S0 frame size, designed for switching motor loads and resistive circuits in industrial control panels. It carries a 48 VDC coil and uses spring-type terminals for the main and auxiliary circuits — no screw torque to verify, no periodic retightening on a vibrating panel door. The contactor mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 60715, and the mounting position allows ±180° rotation on a vertical surface plus ±22.5° forward/backward tilt — useful when the panel layout forces an unconventional orientation.
DC switching capability and coil data
For DC load switching, the 3RT2025-2BW40 is rated at 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V — these are the maximum continuous currents the main contacts can interrupt under DC conditions, which are more demanding than AC due to the lack of a natural zero-crossing. The coil pick-up and drop-out timing is specified at 15…17.5 ms at DC, with an arcing time of 10…10 ms. The coil holds at 48 VDC nominal; the initial pick-up value is 0.8 × rated voltage, and the full-scale operating range is 1.1 × rated voltage.
Physical integration and wiring
Dimensions are 107 mm deep, 45 mm wide, and 102 mm tall — the S0 frame is a compact footprint that fits standard panel layouts. Required clearances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the sides. Spring-type terminals accept solid or stranded conductors from 1…10 mm², and two conductors of 0.5…2.5 mm² can be paralleled in the same clamp. The auxiliary switch is included as standard.
Lifecycle and sourcing posture
Operating temperature range is -25…+60 °C during operation, with storage from -55…+80 °C. The contactor's mechanical endurance is rated at 10 million operating cycles typical.