There are two connection methods:
1. Simply connect two phases of three-phase electricity. Never connect the neutral wire, otherwise it will become 220V electricity.
2. There is also a three-phase. Simply connect the three live wires to electrical devices. If there are steering devices. Just swap the two lines arbitrarily.
The difference between three-phase power and single-phase power: The power generated by the generator is three-phase. Each phase of the three-phase power supply (x, y, z in Fig. 1) is connected to its neutral point. (For example, O0 can form a single-phase circuit to provide power to users. Note that the AC circuit here cannot be called positive pole or negative pole. It should be called the phase line (called live wire in civil electricity) and the neutral line (called the zero line in civil electricity
). Detailed information:
Three-phase power refers to the part number power channels on the motherboard, which is often called the number of power phases. Three-phase power refers to the number of phases of the computer motherboard power supply.
Three-phase alternating current has many advantages over single-phase alternating current. It has obvious advantages in power generation, transmission and distribution, as well as the conversion of electrical energy into mechanical energy. phase generators and transformers save materials compared with single-phase generators and transformers of the same manufacturing capacity, are simple in structure and have excellent performance. Another example is that the capacity of a three-phase motor made with the same materials is 50%. bigger than thatof a single-phase motor.
When transmitting the same power, three-phase AC power can save 25% of non-ferrous metals compared with single-phase power transmission and power loss. is lower than that of single phase AC power
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As shown in the figure, which generator is the neutral wire and the live wire?
The differences are as follows:
1. Star Connection: Star connection refers to connecting the three-phase ends of the motor windings together, the first end of the three. The phases are the power end, and the output voltage is 220V. The starting output power is small, and it is often used for small power motors with high torque or larger power motors, this qwhich will result in less losses for the machine.
2. Triangle connection method: The triangle connection method refers to the three connections. The phase windings are connected at the beginning and end, and the three end points are the power terminals. , the delta connection method is used after the motor begins to operate normally.
3. When the delta connection is used, each winding of the three-phase motor carries the line voltage (380 V). In star connection, each motor is subjected to a phase voltage (220 V) when the motor power is the same. In this case, the winding current of the angle-connected motor is lower than that of the star-connected motor.
Detailed information:
The triangular connection method of the motor is to connect each enroululation of phase end to end in turn and to bring out each point connected as three-phase wires of three-phase electricity. In delta connection, the motor phase voltage is equal to the line voltage; the line current is equal to the phase current three times the square root.
Star connection
The star connection of the motor is to connect one end of each phase winding to a point, and their other ends are used as lead wires, each of which is of three phase lines. In star connection, the line voltage is three times the root of the phase voltage and the line current is equal to the phase current.
Since the power output of the star connection is low, it is often used for low-power, high-torque motors, or when starting motors with higher horsepower. This will cause less losses for the machine then. move to triangleafter normal operation. This is often called star-triangle initiation.
Selection of motor connection method
This is a three-phase motor, and single-phase motors do not have the above two connection methods. Generally, motors under 3 kW have a star connection and motors over 3 kW usually have an angle connection. According to regulations, motors over 15 kW require star start angle operation to reduce starting current.
There are also small angular start motors. If they are to be connected to a three-phase 220 V supply, they must be star connected.
The three-phase power supply has two connection methods: star and delta on the power side and the load side. Both connection methods will have three three-phase transmission lines and three power supplies (or loads), but the methodsconnection of the power supplies (or loads) are different.
The voltage in the three-phase four-wire system of the daily power system is 380/220 V, that is, the phase voltage is 380 V. The phase voltage varies depending on the wiring method in case of star connection; The method is used, the line voltage is 220 V, the phase voltage of the triangle connection is 380 V.
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The neutral line also comes from the power plant. The line is the neutral line. The generator only has three phases, but when passing through the step-down transformer (DY connection), the secondary side of the transformer brings a cable out from the neutral point. This is called the neutral line, which is also the zero line. mentioned by the poster.
The fait that the poster can think about the final destination of the neutral line shows that the poster is also a person who likes to think. Our electrical network is a mesh structure, and the neutral line comes out of it. this transformer will eventually be connected to another transformer.
I also suggest that the poster takes a look at the TN system. The neutral wire should be grounded.