What it is and where it fits
The Siemens SIRIUS S2 power contactor 3RT2035-3AB00-1AA0 is a size S2 frame contactor with spring-type terminals on the magnet coil and a built-in auxiliary switch. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, standing on a horizontal surface — standard panel integration for a control cabinet.
Key ratings and what they mean for the panel
Rated for AC-1 maximum switching rate of 1 200 operations per hour, AC-3 at 1 000 ops/h, and AC-4 at 300 ops/h. That AC-3 figure is the one that matters for motor loads — it tells you the contactor can handle the make/break duty of starting a squirrel-cage motor under full load at that pace. The AC-4 rate is lower because reversing or inching duty puts more arc wear on the contacts. Auxiliary contact ratings span 24 V at 10 A up to 500 V at 2 A, covering control-circuit needs across common control voltages. The 480 V rating at 40 A on the main contacts confirms this contactor handles 480 V motor circuits — common in North American 480Y/277 V panels.
Panel fit — dimensions and clearances
The contactor measures 55 mm wide, 114 mm tall, and 130 mm deep. Minimum clearances around the unit: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. That 130 mm depth is the full body depth — check your enclosure depth if the contactor sits near the backplane or behind a gland plate.