The Siemens 3RT2038-1CP04 is a SIRIUS power contactor in size S2, rated for 65 A in AC-3 duty — that's the motor-switching current for a load up to that rating, so it handles a 30 kW motor at 400 V without derating. Screw-type terminals on the magnet coil, and the main contacts are screw-clamp as well, accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire. Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, with +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward allowed.
Duty Cycles & Switching Frequency
Mechanical endurance is typical at 10,000,000 operations. Electrical switching frequency depends on duty: 700 cycles/hour at AC-1 (resistive), 500 at AC-3 (motor starting), 350 at AC-2 (slip-ring motor), and 150 at AC-4 (plugging/inching). Arcing time runs 10 to 20 ms; the relay closing time is 10 to 18 ms. Ambient operating range is -25 to +60 °C, storage from -55 to +80 °C.
Integration & Panel Fit
The contactor body measures 114 mm high, 55 mm wide, 174 mm deep. Side clearance to adjacent devices is 6 mm; forward and upward spacing 10 mm; downward 10 mm. The S2 size means it fits the standard SIRIUS mounting footprint — mates with the 3RT19 series overload relays and 3RA6 series soft starters. No auxiliary switch block is fitted as standard, but the slot accepts the SIRIUS auxiliary contact range.