The Siemens 3RK1300-0KS01-1AA4 is an electromechanical reversing starter from the SIRIUS family, designed for direct-on-line reversing of three-phase motors up to 0.37 kW at 400 V AC-3 duty. It integrates a bimetal overload relay with a setting range of 0.9 to 1.25 A, so the same device handles motor protection and reversing contactor function in one package — no separate overload relay to wire. That saves panel space and cuts installation time on conveyors, packaging lines, or food-processing equipment. PROFIBUS DP is onboard, so the starter reports motor status and accepts reversing commands over the fieldbus — no extra gateway or I/O block needed. The integrated motor brake output handles DC braking for holding loads, with a brake contact rated DC 500 V / 1 A.
The 3RK1300-0KS01-1AA4 measures 270 mm high by 140 mm wide by 134 mm deep. The form factor is sized for direct machine mounting — not a standard DIN-rail footprint — so plan for screw-fixing or a backplate. Ambient operating temperature range is 0 to 55 °C, which covers most industrial hall conditions but not freezer or high-temp oven zones. The short-circuit breaking capacity at 400 V is 50 A, adequate for branch-circuit protection when coordinated with a suitable upstream MCCB or fuse.