What the ratings mean for fit
The Siemens 3RT2035-1AC24 is a SIRIUS power contactor in size S2, rated for 40 A at 480 V — that's the AC-1 resistive load curve, so it handles heating elements, lighting banks, and non-inductive loads up to that current. The 24 V 50 Hz coil pulls 6 A inrush at rated voltage, which means the control transformer or PLC output driving it needs to source that peak without dropping below the dropout threshold. Mechanical life is 10 million cycles typical, so this is built for high-cycle applications like conveyor indexing or press control where the contactor sees frequent operation.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The S2 footprint is 55 mm wide, 114 mm tall, 174 mm deep — that's a standard three-module-wide slot on the rail, so it fits alongside a motor-protective circuit breaker or overload relay in a typical motor starter lineup. Clearance requirements: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side. The contactor can be rotated ±180° on a vertical mounting surface, and tilted forward/backward ±22.5°, which gives flexibility in tight enclosures.
Coil and switching performance
Coil is screw-type terminals, accepting 2x 0.5–1.5 mm² or 2x 0.75–2.5 mm² solid or stranded. Arcing time is 10–20 ms, and the contactor can switch at up to 1,200 operations per hour at AC-1, 1,000 at AC-3, and 300 at AC-4. The main contacts are 1 NO (normally open) — no auxiliary switch built in, so if you need a feedback contact for the PLC, you'll add a separate auxiliary contact block. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.