The Siemens 3RT1044-1AP00 is a SIRIUS S3-frame power contactor rated for motor switching at 30 kW in AC-2 duty at 400 V, and 55 A in AC-4 duty at 400 V — the AC-4 figure governs reversing and plugging applications where the contactor makes and breaks stalled rotor current.
At 70 mm wide by 146 mm high by 139 mm deep, the S3 frame fits standard motor-starter footprints; the IP20 front enclosure with IP00 terminal area means the contactor is protected against finger contact on the front but the lug area is live — plan for terminal shrouds or a cover/box terminal accessory if the panel has a higher touch-protection requirement.
Coil operates at 50 Hz with a voltage tolerance factor of 0.8 to 1.1 times rated; the 24 V DC coil draws 10 A inrush, dropping to lower hold-in current. Mechanical life is typical 10 million operations; maximum switching rates are 1000 cycles/hour at AC-1 and AC-3, 400 at AC-2, and 300 at AC-4 — the AC-4 rate is the limiting factor for frequent reversing duty.
RoHS compliance date is 05/01/2012, covering the EU RoHS substance prohibitions. The part carries no UL/CSA/CE mark in the available spec record — verify with the factory or a local Siemens representative if your panel requires third-party certification.