S2 contactor, AC-3 rated, screw terminals
The Siemens 3RT7037-1AP00 is a SIRIUS S2-size contactor with three normally-open main poles, screw-type terminals on both main and auxiliary circuits, and an AC coil. It is rated for AC-3 switching up to 690 V, with a maximum operating rate of 800 switching cycles per hour under AC-3 duty. The front face carries an IP20 rating; the terminals themselves are IP00. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, and side-by-side mounting is permitted without derating.
What the ratings mean for fit
The AC-3 rating at 690 V defines its motor-switching capability — it handles the inrush of a squirrel-cage induction motor up to that line voltage. The 800 1/h maximum at AC-3 means it can cycle a motor start roughly every 4.5 seconds; the AC-4 maximum of 250 1/h applies for plugging or inching duty, where the contacts break stalled-rotor current. The 6 kV rated surge voltage resistance (impulse withstand) tells you it's suitable for 400 V and 690 V industrial networks without external surge suppression. Pollution degree 3 confirms it's rated for the conductive-dust and condensation environment typical of an unsealed control panel.
Panel integration and wiring
Dimensions are 112 mm high, 55 mm wide, 115 mm deep — the S2 frame fits alongside other SIRIUS components on the same DIN rail. The screw terminals accept two conductors per clamp: solid or stranded up to 2.5 mm², or finely stranded with ferrules. The coil draws 0.79 W on closing and holds at 0.36 W DC, so the control transformer sizing is modest. The auxiliary contact block is field-addable (product extension auxiliary switch is supported). Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward or backward, which helps in tight enclosures.