The 3RT1044-1AL00 occupies 70 mm width on a standard 35 mm or 75 mm DIN rail, secured via the integrated snap-on latch or screws through the base.
This is a size S3 power contactor from the SIRIUS family, designed for motor starting and general power switching in control panels. The headline rating is 55 A in AC-4 duty at 400 V — that's the current it can interrupt during inching, plugging, or jogging cycles where the motor is re-energized before it has stopped. For normal AC-3 motor starting (run-up to speed), the contactor handles up to 37 kW at 500 V and 18.6 kW at 690 V. The AC-2 rating of 30 kW at 400 V covers slip-ring motor applications. Resistive loads (AC-1) are switched at up to 1 000 operations per hour; AC-3 allows the same rate, while AC-4 is limited to 300 operations per hour due to the heavier arc stress.
The auxiliary contact block terminals accept 2x (0.5... 1.5 mm²) solid or 2x (0.75... 2.5 mm²) stranded. This covers control wiring from 18 AWG up to power feeds for the S3 frame.
Environmental and protection
The contactor body is rated IP20 on the front with the cover or box terminal installed; the terminal area itself is IP00. This supports installation in unheated enclosures or near process heat sources, as long as the ambient stays within the operating window. The 50/60 Hz coil operates with a voltage tolerance of 0.8 to 1.1 times the rated value at 50 Hz.