The Siemens 3RT1044-3BB40-ZX95 is a SIRIUS-branded power contactor in frame size S3, rated for motor switching up to 37 kW at 500 V and 18.6 kW at 690 V. The 24 VDC coil pulls in at 0.8 of rated voltage and drops out below that threshold, with an arcing time of 10 to 15 ms at DC and a DC switching window of 14 to 20 ms. Main circuit connections use screw-type terminals accepting 2x (10 to 50 mm²) stranded or 2x (2.5 to 16 mm²) solid/stranded; control terminals take 2x (0.25 to 2.5 mm²) solid.
AC-3 switching at 1000 operations per hour is the motor-duty benchmark — this contactor handles frequent starting of squirrel-cage motors at that rate. The IP20 front enclosure with optional cover/box terminal protects against finger contact; the terminal block itself is IP00, so panel builders must maintain clearance in the wiring compartment.
Dimensions are 70 mm wide, 146 mm high, 152 mm deep — fits standard S3 panel cutouts.