The relationship between line current and phase current is as follows

For a star connected motor, the phase current is equal to the line current.

For motors with triangular connections, the line current is equal to √ 3 times the phase current, and the line current lags behind the phase current by 30 °.

Phase current refers to the current flowing through each phase load in a three-phase power supply. Represented by Iab, Ibc, and Iac. Line current refers to the current in each wire of a three-phase power supply, represented by IA, IB, and IC.

The practical application of three-phase current

Our country produces and distributes three-phase AC power. Three phase alternating current has many advantages, such as using three-phase alternating current in electric motors, generators for energy and material conservation, and convenient maintenance

The three-phase AC power used in industry, some of which directly comes from three-phase AC generators, but most of it still comes from three-phase transformers. For loads, they are all three-phase AC power sources, and in low voltage power supply, three-phase four wire system is often used.

In the three-phase four wire power supply, the three coils of the three-phase AC power supply adopt a star (Y-shaped) connection method, which connectsthe ends X, Y, and Z of the three coils together to form a common point of the

three coils, usually referred to as the midpoint or zero point, and represented by the letter O.

When supplying power, four wires are led out: the wire leading out from the midpoint O is called the neutral or neutral wire; The three wires leading out from the first end of the three coils are collectively referred to as phase wires or

live wires. In a star connection, if the midpoint is connected to the ground, the midpoint is also known as the ground wire. The four wires introduced in our common three-phase four wire power supply equipment are three live wires

and one ground wire.

The voltage between each live wire and the ground wire is called phase voltage, and its effective value is represented by UA, UB, UC; The voltage between live wires is called line voltage, and its effective value is represented

by UAB, UBC, and UCA. Because the phase difference of the AC voltage generated by the three coils of a three-phase AC power supply is 120 °, when the three coils are connected in a star shape, the line voltage is equal to twice

the phase voltage.