The Siemens 3RW3038-1BB14 is a SIRIUS soft starter rated 72 A at 40 °C (derates to 62 A at 50 °C, 60 A at 60 °C). That 72 A figure is the AC-53a motor-starting current — it handles the inrush of a 37 kW motor on 400 V three-phase, but the continuous bypass carries the full load. The integrated bypass contact system means the thyristors are shorted out after start, so no heat sink derating for sustained running; the bypass takes the steady current. Control supply is 110–230 V DC, which is common for 24 V DC panels with a DC/DC converter or a separate control transformer — verify your control voltage matches before wiring. Size S2 means the footprint is 55 mm wide, 160 mm high, 170 mm deep. Clearance: 60 mm above, 40 mm below, 30 mm at the sides — tight for a 72 A device, so plan the enclosure layout accordingly. Minimum load is 10 %.
Terminal and wiring notes
Solid wire: 2x (0.5 … 2.5 mm²); stranded: 2x (1.5 … 25 mm²). Auxiliary and control circuits also screw-type, accepting 2x (20 … 14 AWG). The back clamping point accepts 16 … 2 AWG; the front clamping point accepts 18 … 2 AWG. Using both clamping points: 2x (16 … 2). That's a wide range — fine for panel wiring with ferruled stranded up to 25 mm² on the power side.