The Siemens 3RT2446-6NB30 is a SIRIUS power contactor in the S3 frame size, rated for AC-1 resistive loads at 140 A and 690 V at 40 °C. It switches motor loads up to 45 kW at 400 V (AC-3 duty) and handles 75 kW at 690 V, making it a fit for medium-horsepower induction motors on pumps, fans, and compressors in a 400 V or 690 V plant distribution. The coil accepts 20-33 V AC/DC with an integrated varistor for surge suppression — no external snubber needed on the control transformer. Holding current averages 75 mA, so the control transformer sizing is modest even across a long daisy chain of contactors. Lifecycle status is active, so this is a current-production part, not a phase-out item.
Switching frequency and inrush behavior
Rated for up to 850 operations per hour in AC-3 and AC-3e duty — that is about one cycle every 4.2 seconds, which covers most conveyor and pump cycling but not high-speed indexing. The inrush current peak is 6.5 A lasting 50 µs, and the locked-rotor current holds at 3.2 A for 150 ms. Those numbers matter when coordinating the upstream breaker or fuse: the inrush is short enough that a C-curve MCB or gG fuse will ride through, but the locked-rotor duration could trip a fast electronic relay if the motor stalls.
Motor power across voltages
Rated motor power at 230 V is 22 kW, at 400 V it is 45 kW, at 500 V it is 55 kW, at 690 V it is 75 kW, and at 1000 V it drops to 37 kW. The 1000 V rating is lower because the contactor's insulation voltage is 1000 V — at the ceiling of its rated voltage, the switching capacity derates. For a 690 V line, this contactor covers a 75 kW motor; for a 400 V line, 45 kW. That is a solid match for a 55 kW motor at 500 V or a 37 kW motor at 1000 V.
Substance prohibitance date is June 12, 2019, indicating RoHS and REACH compliance for that cutoff. The contactor carries the SIRIUS brand and is designed to IEC/EN 60947-4-1. No UL or CSA listing is explicitly in the evidence, but the SIRIUS line typically holds those approvals for North American panels — verify the specific UL file number on the nameplate if the panel requires a marked device.