The Siemens SIRIUS 3RW3035-1AA12 is a soft starter in size S2, carrying a rated operating current of 38 A at 40 °C — that's the current it delivers continuously through the thyristor stack at that ambient. Derate to 32 A at 50 °C and 27 A at 60 °C, so if the panel sits near a curing press or other heat source, size the motor load against the derated figure, not the 40 °C headline. The control supply accepts 110-230 VDC, which covers common DC bus voltages in industrial panels; no separate AC control transformer needed. An integrated bypass contact system means the thyristors are shorted out once the motor reaches full speed — the bypass carries the running current, not the semiconductors. That cuts heat dissipation in the enclosure and extends the life of the power stack. No external bypass contactor or wiring needed; it's built in. Minimum load is 9 % of the rated current — the soft starter can regulate down to about 3.4 A before the firing angle control loses precision. Below that, the motor may not start smoothly. For very small motors, oversize the starter or check the application note.
Clearance: 60 mm above, 40 mm below, 30 mm at the sides for airflow and wiring access. Power wiring lands on screw-type terminals sized for 2x (1.5... 25 mm²) stranded or 2x (0.5... 2.5 mm²) solid — the larger cross-section handles the 38 A feed without doubling up. Auxiliary control wiring uses the front or back clamping points accepting 16... 2 AWG. Maximum wire length from starter to motor is 100 m; beyond that, voltage drop and reflected-wave effects on the thyristors need evaluation. Mounting position is vertical with the surface, rotatable ±10° or tiltable ±10° front-to-back. That's enough to align the display in a sloped panel door without derating.