Which alternator configuration has three legs that all connect in the middle?

The Wye configuration, also known as the Star configuration, features three legs that connect at a common center point. This method allows for improved voltage regulation and a better balance of loads across each phase. In a Wye configuration, each leg represents one phase of the alternating current (AC), and the center connection often serves as a neutral point, which can handle unbalanced loads effectively.

In contrast, the Delta configuration connects each leg end-to-end, forming a closed loop and does not provide a neutral point for balance. The other configurations, namely series and parallel, are related to arranging components in a circuit rather than specifically addressing the phase connections of an alternator.

This makes Wye the correct answer, as it uniquely describes a configuration where all three phases converge at a central point, essential for specific electrical applications and stability.