What is Three Phase Supply?

A Three-phase supply is comprised of 3 single-phase supplies. This means that the first sine wave starts at 0 degrees, the second at 120 degrees, and the third phase sine wave starts at 240 degrees.

We can represent a Three-phase System as follows: 1st Phase: Sin(ωt), 2nd Phase: Sin(ωt + 120 degrees), 3rd Phase: Sin(ωt + 240 degrees), where ω is the Angular Frequency of the Sine Wave, t is the Time variable, and Sin represents the Sine Function.

  • We can denote as
  • 1st phase : Sin(wt)
  • 2nd phase: Sin(wt+120degree)
  • 3rd phase: Sin(wt+240degree)
  • w -Angular Frequency of Sin Wave
  • t- It is Time Variable
  • sin- Sine Function

Three-phase supply is more powerful compared to signal-phase supply.

It is widely used in the electrical power system, from power generation and power transmission to distribution.

how to check voltage in 3-phase supply?

In a 3-phase supply, there are three power lines: L1, L2, and L3.

To check voltage, connect a multimeter between any two wires, as shown in the figure.

Most Common Three Phase Connection Type.

1. Y connection

  1. All three phases are connected at a common central point by forming a Y shape.
  2. The central point where all three phases meet is called the Neutral point.
  3. As it has a neutral reference, it is widely used in power distribution purposes.

2. Delta connection

  1. All three phases are connected in a triangle shape.
  2. At both ends of each phase, the other two phases are connected to form a triangle shape.
  3. It doesn’t have neutral points.
  4. It is mainly used to supply high power requirements for motors and high-current industrial loads.

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