In a three-phase system, what is the phase difference between each line?

In a three-phase system, what is the phase difference between each line?

• A. 90 degrees
• B. 120 degrees
• C. 180 degrees
• D. 360 degrees

Answer: (B)

In a three-phase system, each of the three phases is separated by a phase difference of 120 degrees. This means that the voltage waveforms of each phase reach their maximum and minimum values at different points in time, ensuring a more balanced and efficient distribution of power. The 120-degree phase separation is critical for maintaining the smooth operation of three-phase motors and generators, as it allows for continuous power delivery. When one phase is peaking, the other two phases are either at a negative peak or crossing zero, which contributes to a more stable power output. This design minimizes fluctuations in voltage and current, resulting in a more reliable power system that can efficiently drive electrical loads. The other options do not align with the structure of a three-phase system. A 90-degree phase difference is characteristic of a two-phase system, whereas 180 degrees represents an opposite phase, typically seen in single-phase systems where two currents are out of phase. Finally, 360 degrees would imply a full cycle, not relevant to the phase relationships in a three-phase context.

In a three-phase system, each of the three phases is separated by a phase difference of 120 degrees. This means that the voltage waveforms of each phase reach their maximum and minimum values at different points in time, ensuring a more balanced and efficient distribution of power.

The 120-degree phase separation is critical for maintaining the smooth operation of three-phase motors and generators, as it allows for continuous power delivery. When one phase is peaking, the other two phases are either at a negative peak or crossing zero, which contributes to a more stable power output. This design minimizes fluctuations in voltage and current, resulting in a more reliable power system that can efficiently drive electrical loads.

The other options do not align with the structure of a three-phase system. A 90-degree phase difference is characteristic of a two-phase system, whereas 180 degrees represents an opposite phase, typically seen in single-phase systems where two currents are out of phase. Finally, 360 degrees would imply a full cycle, not relevant to the phase relationships in a three-phase context.