What it is and what it fits
The Siemens 3RT7036-1AN20 is a Size S2 3-pole contactor with screw-type terminals for the main and auxiliary circuits. It carries three normally-open main contacts and is rated for insulation voltage up to 690 V. The front face is IP20; the terminals are IP00, so expect that in a panel environment — no washdown protection here, but that's normal for a panel-mounted contactor. Mounts on 35 mm standard mounting rail per DIN EN 50022, either by screw or snap-on. You can rotate it ±180° on a vertical surface or tilt it ±22.5° forward/backward — handy when you're squeezing it into a crowded panel and need to orient the wiring access.
Key ratings and what they mean for your load
The auxiliary contact ratings are given at three voltages: 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V. That's the contact's ability to break a resistive or lightly inductive load at those voltages — don't try to switch a motor directly through the aux contacts; that's what the main poles are for. The main circuit is rated for AC-3 and AC-3e duty up to 690 V, with a maximum switching rate of 800 operations per hour for AC-3 and AC-3e, and 250 ops/h for AC-4 (plugging/inching). The coil draws 0.36 A at 50 Hz and 0.38 A at 60 Hz. Closing power of the magnet coil is 0.76 W DC; holding power drops to 0.35 W DC. That low holding power means the coil runs cool in continuous duty — less heat build-up in a tight panel. Shock resistance is rated at 15g for 5 ms and 8g for 10 ms under sine pulse — tough enough for most industrial machinery, but if you're mounting it on a vibrating conveyor or a press, you'll want to check your own shock profile against those numbers.