What This Contactor Is and Where It Goes
The Siemens 3RT7037-1AH00 is a SIRIUS size S2 contactor with three normally-open main poles. It's rated for AC-3 switching duty up to 690 V, which covers most three-phase motor loads up to that line voltage. The control supply is AC only, so don't plan on wiring a DC coil into this unit. It fastens with screws or snaps onto a 35 mm DIN rail per EN 50022, and the mounting position allows ±180° rotation on a vertical surface plus ±22.5° tilt forward or back. That's a lot of flexibility for tight panel layouts. The front face carries an IP20 rating, meaning finger-safe against accidental contact, but the terminal area is IP00 — bare live parts when the panel door's open. Keep that in mind for touch-safe installation requirements.
Key Ratings and What They Mean for Your Load
Three main poles, all normally open, handle the power circuit. The AC-3 maximum operating voltage is 690 V, so it'll switch a 400 V motor without issue. For DC-13 loads at 220 V, the rated current drops to 0.3 A — that's a solenoid or brake coil, not a motor. The auxiliary contact reliability is specified as acceptable for PLC control at 17 V, 5 mA. That means the contacts are designed to switch low-energy signals without the oxidation problems that plague standard power contacts on PLC inputs. Fuse coordination is specified: for type 2 coordination, use a 100 A gL/gG NH 3NA fuse; for type 1, a 160 A fuse of the same class. That's the short-circuit protection the manufacturer expects for this contactor size. The magnet coil draws 0.79 W on closing and holds at 0.36 W DC. That's a low holding power, which keeps the coil cool in continuous-duty applications like conveyors or pumps.
Panel Fit and Wiring Notes
Dimensions are 55 mm wide, 112 mm tall, and 115 mm deep. That's the S2 frame footprint — it'll sit next to other SIRIUS S2 components on the same DIN rail without extra spacing, since side-by-side mounting is allowed. Main and auxiliary/control circuits both use screw-type terminals. The wire range accepts 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded, with or without ferrules. That covers standard control wiring up to about 14 AWG. The contactor accepts an auxiliary switch block as a product extension, so you can add feedback contacts for PLC status monitoring without replacing the whole unit.