Three-Phase Industrial Power (Different from Household Single-Phase Electricity)

First, let’s understand what phase means:
(phase: phase angle in physics; also refers to the coil winding in electrical systems).
From this we can see that the difference between three-phase power and household electricity is not simply “more wires”, but the difference in electrical phase angles between multiple windings.
So how does the current actually change in these windings?

In a three-phase circuit, the phases are usually labeled U phase, V phase, and W phase as circuit identifiers.

The electromotive force relationships are:

• U phase leads V phase by 120°
• V phase leads W phase by 120°
• W phase leads U phase by 120°
  
  

This repeating relationship forms the cyclic phase sequence of the electromotive force.