In a three-phase power system, how many electrical degrees are each conductor out of phase with the others?

In a three-phase power system, each conductor is separated by a phase difference of 120 degrees. This means that when one phase reaches its peak voltage, the other two phases are at different points in their voltage cycles, specifically, 120 degrees behind and 240 degrees behind, respectively. This configuration ensures that power delivery is balanced and continuous, minimizing pulsations in the power output.

The choice of 120 degrees corresponds to the fundamental characteristics of three-phase systems, which are designed to provide a consistent supply of power. By spacing the phases this way, the system achieves a smoother delivery of electrical energy, which is one of the primary advantages of three-phase power over single-phase systems.

The other options represent different degrees that do not reflect the phase separation in a standard three-phase system. For instance, 90 degrees is typically related to the phase difference in two-phase systems or represents the quarter cycle of a sinusoidal wave, while 180 degrees indicates complete opposition between two phases, which does not apply in a balanced three-phase system. Finally, 360 degrees represents a full cycle, not the phase displacement between the phases. Therefore, 120 degrees is the correct and relevant separation in a three-phase power system.