Explain how a reduced-voltage motor starter functions and the benefits it provides compared to an across-the-line starter.

A reduced-voltage motor starter is a device that starts an electric motor at a reduced voltage, gradually increasing the voltage to the motor's full rated voltage. This is in contrast to an across-the-line starter, which applies the full voltage to the motor immediately upon starting. When a motor is started across-the-line, it draws a very high inrush current, typically 6 to 8 times the motor's full-load current. This high inrush current can cause voltage dips in the power system, potentially affecting other equipment connected to the same circuit. It also places significant stress on the motor windings and connected mechanical equipment. A reduced-voltage starter reduces the inrush current by starting the motor at a lower voltage. There are several types of reduced-voltage starters, including autotransformer starters, part-winding starters, and solid-state starters (soft starters). Autotransformer starters use an autotransformer to reduce the voltage applied to the motor during starting. Part-winding starters connect only a portion of the motor windings during starting, reducing the current. Solid-state starters use solid-state devices, such as silicon-controlled rectifiers (SCRs), to gradually increase the voltage applied to the motor. The benefits of using a reduced-voltage starter compared to an across-the-line starter include reduced inrush current, which minimizes voltage dips and stress on the power system; smoother acceleration, which reduces mechanical stress on the motor and connected equipment; and increased motor lifespan, due to reduced stress on the motor windings. Reduced-voltage starters are typically used for larger motors, where the high inrush current of across-the-line starting would be problematic.