Integrator's first look — 3RT7037-1AN20
The Siemens 3RT7037-1AN20 is a Size S2 SIRIUS contactor — three main poles, all normally open, rated for AC-3 switching up to 690 V maximum. Screw-type terminals on both main and auxiliary circuits, with IP20 protection on the front face and IP00 at the terminal block itself. Coil holds at DC with 0.35 W holding power, pulls in at 0.76 W. Surge voltage resistance is 6 kV, insulation rated at 690 V.
Panel fit and mounting
Snaps onto 35 mm DIN rail per DIN EN 50022, or screws directly to the backplate. Width is 55 mm, depth 115 mm, height 112 mm — occupies one standard modular slot. Side-by-side mounting is allowed, so no mandatory spacing between contactors on the rail. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward.
Coordination and protection
For type of coordination 2 (no welding under short-circuit), the required backup fuse is a gL/gG NH 3NA: 100 A. For type of coordination 1 (welding allowed), the same fuse type at 160 A. Pollution degree 3 applies — suitable for industrial environments with conductive contamination. Mechanical shock resistance is 15g for 5 ms sine pulse, 8g for 10 ms.