The Siemens 3RT7037-1AH20 is a SIRIUS S2-size 3-pole contactor with screw-type terminals for main and auxiliary circuits. The 55 mm width and 112 mm height fit a standard 35 mm DIN rail (DIN EN 50022) with screw and snap-on fastening; side-by-side mounting is supported, and the mounting position allows ±180° rotation on a vertical surface plus ±22.5° tilt forward/backward. The IP20 front enclosure protects against finger contact during panel access, while the terminal area is IP00 — bare terminals, so the contactor relies on the panel enclosure for overall ingress protection.
Rated insulation voltage is 690 V, and surge voltage resistance is 6 kV — this contactor is built for 400/480 V panels with headroom for 690 V systems. The AC-3 and AC-3e maximum operating frequency is 800 operations per hour; for AC-4 (plugging/reversing) it drops to 250 1/h. That 800 1/h figure governs how fast you can cycle the contactor under motor load — exceeding it risks overheating the coil or welding the contacts.
Integration notes for panel builders
Screw terminals accept 2x (0.5…1.5 mm²) solid or stranded, or 2x (0.75…2.5 mm²) finely stranded with ferrule. The auxiliary switch extension option is supported — you can add a side-mount auxiliary block without changing the contactor body. For short-circuit protection, Type 1 coordination requires a gL/gG NH 3NA fuse rated 160 A; Type 2 requires 100 A. The shock resistance is 15g for 5 ms and 8g for 10 ms sine pulse, so it withstands typical panel vibration from adjacent contactors or drives.