The RSE4812-BS38 is a compact AC soft starter motor controller designed for smooth starting and stopping of three-phase squirrel-cage induction motors. It operates at a nominal supply voltage of 480 VCA rms (±15%, 50/60 Hz) with a rated output current of 12 A in AC-53b category, featuring an integrated semiconductor bypass for enhanced reliability. The device provides independent adjustment of start ramp time, stop ramp time, and initial starting torque (70–100%) through potentiometers, with ramp times ranging from 1 to 7.5 seconds. Control input accepts 24–110 VCA/CC or 110–480 VCA (±15%), with a minimum load current of 200 mA AC rms, and includes built-in transient overvoltage protection and LED indicators for power and operation status. This controller is ideal for applications requiring soft motor acceleration to reduce mechanical stress, inrush current, and energy consumption in industrial motor control systems.