SIRIUS S0 contactor with DC coil — what the ratings mean for your panel
The Siemens 3RT2325-1BM40-ZX95 is a SIRIUS S0 frame contactor with a DC coil rated at 220 V. The DC coil type means it holds in without hum and drops out cleanly — no AC ripple to filter. Rated operating current on the main contacts at 230 V is 10 A, which is the figure to size motor loads against in AC-1 duty. At 400 V the same contacts carry 3 A, so the voltage derating is real: if your line runs 400 V three-phase, that 3 A is the hard limit, not the 10 A at 230 V. Mechanical life is rated at 10,000,000 cycles typical. Arcing time is 10 ms. Mounting is screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The S0 frame footprint is 60 mm wide, 85 mm high, and 107 mm deep. Clearance requirements: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. That side clearance is tighter than the vertical — if you're packing contactors side-by-side in a panel, the 6 mm gap is the binding constraint for heat dissipation and arc flash separation.
Wire termination and auxiliary contacts
Main contacts accept stranded wire from 1 to 10 mm², or solid wire in two ranges: 2x (0.5... 1.5 mm²) and 2x (0.75... 2.5 mm²). Coil terminals are screw-type. The contactor includes an auxiliary switch and can accept up to 2 attachable auxiliary contact blocks.
Coil characteristics and operating conditions
The DC coil picks up at 0.8 times rated voltage and drops out at 1.1 times rated voltage. Operating time at DC is 15 to 18 ms. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The mounting position allows +/-180° rotation on a vertical surface and can be tilted forward/backward by +/-22.5° on a vertical mounting surface. That flexibility helps in tight enclosures where the DIN rail isn't perfectly level.