In a three-phase generator the degree of separation between each phase is ______.

• A. 120°
• B. 90°
• C. 180°
• D. 60°

Answer: (A)

Three-phase systems are built so that the voltages are evenly spaced in time. Each phase is separated by 120 degrees, so the phase voltages reach their peaks one-third of a cycle apart. In phasor form, the three vectors sit 120 degrees apart around the circle, which keeps the instantaneous sum of the voltages in balance and provides smooth, constant power delivery to a load. Angles like 90°, 180°, or 60° would not produce that even, balanced arrangement, so they don’t describe a proper three-phase set. Therefore, the separation between each phase is 120 degrees.