What this contactor is and what it carries
The Siemens 3RT2037-1AH00 is a SIRIUS power contactor, Size S2, rated to switch motor loads at 65 A in AC-3 duty at 480 V — that's the figure that decides whether it fits a 30 to 50 hp motor circuit on a 480 V line. It pulls in with a 48 V 50 Hz coil, so the control transformer needs to match that voltage. Screw-type terminals on the magnet coil and main contacts accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire. An integral auxiliary switch is built in, rated 10 A at 24 V and derating down to 0.3 A at 220 V, so it can drive a PLC input or a pilot light without a separate relay block. The contactor also carries a 10 hp rating at 230 V for single-phase or lower-voltage three-phase loads.
Mounting and panel fit
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. Dimensions are 55 mm wide, 114 mm tall, and 130 mm deep, so it takes up a standard S2 footprint on the rail. Clearance needs: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side — keep those gaps for arc flash and airflow. The mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward or backward by +/-22.5°.
Duty cycle and operating conditions
Rated for 10 million mechanical operations typical, so it'll outlast most panel refreshes. Switching frequency maxes out at 800 cycles per hour for AC-1 resistive loads, 700 for AC-3 motor loads, and 200 for AC-4 plugging/reversing duty. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C — fine for a warm panel room or a cold warehouse. Arcing time runs 10 to 20 ms; operating time (closing) is 10 to 18 ms.