The Siemens SIRIUS 3RT2035-1AP00-1AA0 is a size S2 power contactor, rated for 40 A at 480 V in AC-3 duty — that's the motor-switching rating, so it handles a 40 A induction motor load at that voltage without welding the main contacts. The coil termination is screw-type, and the contactor carries an auxiliary switch block ready for add-on modules, so it's set up for a standard three-wire control scheme right out of the box.
AC-3 maximum switching frequency is 1 000 operations per hour — that's the motor-starting duty cycle; if you're cycling a conveyor or a pump more often than once every 3.6 seconds, you'll need to step up to a larger frame or a dedicated switching contactor. For resistive loads (AC-1), it can handle 1 200 ops/h; for the heavier AC-4 plugging/inching duty, it drops to 300 ops/h — the arcing time sits at 10 to 20 ms, which is typical for this class and tells you the arc chute is sized for the 40 A break. Mechanical life is listed at 10 000 000 typical operations — that's the coil and armature wearing out, not the contacts. The main contact electrical life is 18 to 1 million operations depending on load current and duty, so on a 40 A motor starting once a minute you'll get years of service before the contacts need attention.
Dimensions are 55 mm wide, 114 mm high, and 130 mm deep — the depth is the key number for enclosure depth planning: you need at least 130 mm from the DIN rail face to the back wall, plus clearance for wiring and any auxiliary block. Main power terminals accept 2x 0.5 to 1.5 mm² solid/stranded or 2x 0.75 to 2.5 mm² — that's fine for 40 A motor feeders with standard ring or fork terminals. The coil terminals are screw-type, so no special crimp tool needed.