S2 contactor for motor and resistive loads
The Siemens 3RT7035-1AV00 is a SIRIUS S2-frame contactor with three main poles (3 NO contacts) and an AC control coil. Rated insulation voltage 690 V and surge voltage resistance 6 kV place it in the standard 690 VAC class for industrial motor switching. The AC-3 maximum operating frequency of 800 switching cycles per hour suits frequent start/stop duty on conveyors or pumps; the AC-4 rating of 250 cycles per hour covers plugging or inching applications where the contactor makes and breaks stalled-rotor current. Screw terminals on both main and auxiliary circuits accept up to 2x 2.5 mm² stranded or solid wire. The contactor mounts via screw or snap-on onto 35 mm DIN rail (EN 50022) and allows side-by-side mounting without derating, which simplifies panel layout when grouping multiple contactors on a rail.
Coil power and control circuit considerations
The AC coil draws 0.42 A at both 50 Hz and 60 Hz. Closing power is 0.78 W DC holding power, meaning the coil's inrush is brief and the steady-state thermal load on the control transformer is low. The auxiliary contact block (field-installable) is rated for PLC-level reliability at 17 V, 5 mA — dry-switching compatible, so you can feed a 24 VDC PLC input directly without a separate interface relay. Mounting position is flexible: the contactor can be rotated ±180° on a vertical surface and tilted ±22.5° forward/backward. This helps when fitting into tight enclosures or angled subpanels. Side-by-side mounting is permitted, so no extra spacing is needed between units on the same rail.
Fault coordination and auxiliary ratings
For type of coordination 2 (no-weld condition), the required backup fuse is gL/gG 80 A; for type 1 coordination (allowable weld), 125 A. The auxiliary contact ratings at 230 V AC are 6 A, at 400 V AC 3 A, and at 690 V AC 1 A. DC-13 switching at 220 V is rated 0.3 A. These numbers define the maximum load the auxiliary contacts can break — useful when driving small contactors or indicator lamps directly.