The three-phase system has each sine wave displaced how far from the others?

The three-phase system has each sine wave displaced how far from the others?

• A. 120 degrees
• B. 90 degrees
• C. 180 degrees
• D. 60 degrees

Answer: (A)

In a balanced three-phase system, the three sine waves are equal in amplitude and frequency and are spaced evenly around the 360-degree cycle. Each phase is separated by 120 electrical degrees from the others, so if you take one phase as a reference, the others peak 120 degrees apart (one may be considered 120 degrees ahead and the other 120 degrees behind). This even 120-degree separation is what gives the three phases their symmetrical relationship and leads to smooth, constant power delivery. The other spacings don’t provide that equal three-way symmetry: 90 degrees is typical of quadrature relationships, 180 degrees would place a wave opposite another, and 60 degrees wouldn’t produce the even spacing characteristic of a balanced three-phase system.

In a balanced three-phase system, the three sine waves are equal in amplitude and frequency and are spaced evenly around the 360-degree cycle. Each phase is separated by 120 electrical degrees from the others, so if you take one phase as a reference, the others peak 120 degrees apart (one may be considered 120 degrees ahead and the other 120 degrees behind). This even 120-degree separation is what gives the three phases their symmetrical relationship and leads to smooth, constant power delivery. The other spacings don’t provide that equal three-way symmetry: 90 degrees is typical of quadrature relationships, 180 degrees would place a wave opposite another, and 60 degrees wouldn’t produce the even spacing characteristic of a balanced three-phase system.