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. Coil holds at DC with 0.35 W holding power, pulls in at 0.76 W.
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.
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. Mechanical shock resistance is 15g for 5 ms sine pulse, 8g for 10 ms.