The Siemens SIRIUS 3RT2036-1AD00 is a Size S2 power contactor rated for 52 A at 480 V in AC-3 duty — the standard motor-switching category per IEC 60947-4-1. That rating means it handles the locked-rotor inrush and breaking of an induction motor up to that current without welding the main contacts.
AC-3 at 480 V is the number that decides whether this contactor lives in your motor starter. It carries 52 A continuously and breaks the same current during a stop. The AC-3 electrical life at maximum rate is 800 operations per hour, which is fine for a conveyor or pump cycling at moderate speed; for high-speed jogging you'd derate. That gives you options in a crowded panel. The 55 mm width and 114 mm height fit the standard S2 footprint — same as other SIRIUS S2 contactors, so a panel laid out for a 3RT2028 or 3RT2037 will accept this one without re-drilling the DIN rail.