The Siemens 3RT2037-1AR64 is a SIRIUS power contactor in Size S2, rated 65 A at 480 V in AC-3 duty — that's the motor-switching current, so it handles a 30–40 hp induction motor on a 480 V line without derating. The coil pulls 400 V at 50 Hz (0.36 A holding, 0.39 A at 60 Hz). Screw terminals on the magnet coil; main contacts accept 2x (0.75...2.5 mm²) solid or stranded.
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward — handy when you're squeezing it into a tight panel. Clearance: 10 mm upwards, forwards, and downwards; 6 mm at the sides. Dimensions: 114 mm high, 55 mm wide, 174 mm deep.
Operating temperature range -25 to +60 °C; storage -55 to +80 °C. Mechanical endurance typical 10 million operations. Switching rates: 800 cycles/h at AC-1, 700 at AC-3, 200 at AC-4. Arcing time 10–20 ms; closing time 10–18 ms. No auxiliary switch built in — you'll need a separate block if you're feeding a PLC input or status lamp.