How do we define a Single Phase System?

A Single Phase System is defined as one that is energized by a single alternating voltage. This means that the electrical supply consists of only one sine wave, which alternates between positive and negative values. In practical terms, a single phase system typically involves two conductors: one carrying the alternating voltage and the other as a return path or neutral.

This type of system is commonly used for residential power distribution and smaller applications because it provides a simpler and cost-effective way to supply electricity.

The other choices involve conditions that do not apply to a single-phase system. For instance, multiple alternating voltages would indicate a multi-phase system, which incorporates more than one sine wave for distributing power, typically seen in industrial applications. Direct current systems are characterized by a steady flow of electricity in one direction, which differs entirely from the alternating nature of a single-phase system. Finally, the requirement for three wires pertains to three-phase systems, which utilize three alternating currents to deliver a more stable and efficient power supply, particularly for heavy electrical loads.