# Detailed explanation of electrician terms such as Three-Phase electricity, line voltage, neutral line, live line, line Voltage, etc.

[Introduction]The voltage between the live wire and the neutral wire is 220 volts, called “line voltage”; and the voltage between the two live wires is 380 volts, called “phase voltage”.

What is the relationship between line voltage and phase voltage?
The voltage between the live wire and the neutral wire is 220 volts, called “line voltage”; and the voltage between the two live wires is 380 volts, called “phase voltage”.
The line voltage is the voltage between the two phase wires, and the phase voltage is the voltage between the phase and the neutral point. This is for the star connection, but for the angle connection, there is no neutral point, and the phase voltage is Equal to the line voltage. Because the voltage that each phase winding can withstand is the phase voltage, one of the phase windings in the angular connection is always connected between the two phase wires, that is, one winding is directly connected to the line voltage, so the lowest is Standard, in the angle connection method, the line voltage must be equal to the phase voltage to meet the voltage level of the winding.
It can be understood like this:
1. Three-phase electricity-the three fixed coils in the generator produce three induced voltages when they move in the magnetic field, and the phase angle of each voltage differs by 120 degrees. This is the so-called ABC three-phase in daily life;
2. If the three-phase electrical output connection of the generator adopts the “three-phase four-wire star connection”, there will be one neutral wire and three phase wires;
3. Neutral line-the low-voltage side of the transformer generally adopts Y-type connection. The neutral point is connected to the earth with a wire, and a wire is pulled out at the neutral point. This wire is the neutral line. The advantage of the neutral line is to keep the potential of the neutral point at zero potential, so that the voltage between the phase line (the wires drawn by the phases A, B, and C) and the neutral line remains relatively stable, which is beneficial to the use of electrical appliances.
4. Line voltage and current-the voltage between the phase line and the phase line is called the line voltage (for example, the voltage between the AB phase line, generally 380V), and the current generated by the loop between the phase line and the phase line is called Line current.
Phase voltage, phase current-the voltage between the phase line and the neutral line is called the phase voltage (generally 220V), and the current generated by the loop between the phase line and the neutral line is the phase current.
5. Bus-the main line in the transmission line is called the bus
6. The phase voltage is the voltage between each phase and the ground. The line voltage is the phase-to-phase voltage, that is, the three-phase four-wire system is 380 volts, the phase voltage is 220 volts, and the line voltage is 380 volts.The relationship between the two is 1.732
The difference between line voltage and phase voltage
The line voltage is the voltage between the live wire and the live wire (380V), and the phase voltage is the voltage between the live wire and the neutral wire (220). For phase voltage and line voltage, they may be equal or unequal. If it is a star power connection, the line voltage is definitely not equal to the phase voltage, and the difference between them is √3 times the value, that is, the phase voltage is 220V and the line voltage is 380V. If it is an angular power connection, the line voltage must be equal to the phase voltage, that is, the line voltage is equal to the phase voltage equal to 380V.However, the electricity used in our lives is both 380V and 220V. The star power connection is used in the step-down transformer. Three fires and one zero are three-phase four-wire system.
In a three-phase four-wire power distribution system, phase voltage and line voltage can be matched. The voltage between each phase line and the neutral line of the three-phase power supply is called the phase voltage, and the voltage between any two phases of the three-phase power supply is called the line voltage. U, V, W three-phase line voltage is generally represented by Uuv, Uvw, Uwu, and phase voltage is generally represented by UuN, UwN, Uw N
In a three-phase four-wire AC system, the voltage between any two phase wires is called the line voltage, and the voltage between any phase wire and the neutral wire (zero wire) is called the phase voltage. In our country’s daily circuits, the phase voltage is 220 volts, the line voltage is 380 volts, and the line voltage is 1.732 times the phase voltage, as shown in the formula: 1.732*220=380v. For the phase voltage, it is generally understood that the voltage between the phases is 380V, and the line voltage is understood as 220V.
The phase voltage refers to the voltage between the phase line, that is, the live line and the neutral line, and the line voltage is the voltage of any two live lines ON the line, that is to say, the phase voltage should be 220V, and the line voltage is 380V.
From the power plant are three live wires (line voltage). When using a transformer to boost the output, the point used is to use a step-down transformer to step down to 400V (still the three live wire voltages).
The neutral wire is drawn from the contacts of the three sets of coils of the winding of the step-down transformer. The transformer is star-shaped, and the four wires here are aligned.
The users (loads) are respectively connected through the accompanying power cabinet. The three live wires are generally named A, B, and C, and the zero wire is N. Use 380V line voltage to connect to A, B, C. Our family uses AN, BN, and CN. Both 220V phase voltage. 400 and 380 are not waiting! Yes, the 20V voltage there is consumed in other equipment such as lines. The so-called line voltage refers to the line-to-line voltage 380, and the phase voltage is the line-to-zero voltage 220.