What it is and where it fits
The Siemens 3RT7036-1AH20 is a size S2 contactor from the SIRIUS family, with three main poles for switching motor loads in industrial control panels. It is rated for AC-3 duty up to 690 V maximum, meaning it handles the inrush and breaking of squirrel-cage motors within that voltage range. The front face carries an IP20 rating, so it is protected against finger contact but not against moisture — it belongs inside a panel, not on a washdown line.
Mounting and integration
Mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022. The mounting position is flexible: it can be rotated ±180° on a vertical surface, and tilted forward or backward by ±22.5° on that same surface. Side-by-side mounting is allowed, so you can gang multiple contactors without spacing — useful when panel space is tight.
Electrical ratings and what they mean
The main contacts are three normally open poles. The insulation voltage is rated 690 V, and the surge voltage resistance is 6 kV — that covers the impulse withstand for most 400 V industrial networks. Pollution degree 3 means the contactor is designed for conductive environments (e.g., factory floors with dust and humidity), not just clean control rooms. The auxiliary contacts are rated for PLC-level signals: they are specified as reliable down to 17 V and 5 mA, so they can switch digital inputs without false triggering.
Mechanical endurance and environment
The contactor can handle up to 800 switching cycles per hour under AC-3 duty, and 250 per hour under the harsher AC-4 (plugging/inching) duty. It is shock-resistant to 15g for 5 ms and 8g for 10 ms, so it holds up in applications with vibration — think compressors or conveyors. Operating temperature range is -10 to +55 °C, storage from -25 to +70 °C.