What happens to voltage after a generator has completed a half-turn (180 degrees)?

When a generator completes a half-turn (180 degrees), the voltage generated at that point decreases to zero. This occurs because of the way alternating current (AC) generators work. In an AC generator, the output voltage is produced by the mechanical rotation of coils within a magnetic field. The voltage is generated as the coil cuts through magnetic field lines.

Initially, as the generator begins its rotation, the coil produces a positive voltage, rising towards its maximum value. At 90 degrees, the voltage reaches its peak positive value. However, as the generator continues to rotate towards 180 degrees, the voltage falls back towards zero. By the time the generator completes a half-turn, the position of the coil aligns such that it no longer cuts through the magnetic field in a way that produces voltage, resulting in a reduction to zero.

After this, the generator continues to turn, moving towards 270 degrees, where it will generate negative voltage as it starts cutting through the magnetic field in the opposite direction. Understanding this progression of voltage is crucial for grasping the principles of AC generation and the behavior of electrical grids.