In a three-phase AC power system, by how many degrees is each phase offset?

In a three-phase AC power system, each phase is offset by 120 degrees from the others. This configuration is fundamental to the operation of three-phase systems and is designed to ensure that the power supplied is stable and continuous. The 120-degree phase shift allows each phase to reach its peak voltage sequentially, maintaining a balanced load across the system.

This setup provides various advantages, such as efficient power transmission and the ability to deliver a constant power output, which is particularly beneficial for industrial applications. It also minimizes the ripple effect in the electrical system, reducing the potential for power surges or interruptions.

The other options do not accurately reflect the phase relationship in a three-phase system: 90 degrees is characteristic of a two-phase system, 180 degrees would imply a complete opposition between two phases, and 360 degrees would represent a full cycle of a single phase, which does not apply here. Therefore, the correct offset of 120 degrees is crucial for the effective and balanced operation of three-phase AC systems.