Conversion between the two can be done via a transformer.
The transformer is a device that uses the principle of electromagnetic induction to modify the alternating voltage. Its main components are the primary coil, secondary coil and iron core (magnetic core).
The main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage stabilization (magnetic saturation transformer), etc.
According to the purpose, it can be divided into: power transformers and special transformers (electric furnace transformers, rectifier transformers, industrial frequency test transformers, voltage regulators, mining transformers, audio transformers, medium frequency transformers, high frequency transformers, impact transformers, instrument transformers, electronic transformers, reactors, transformers, etc..).
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Three-phase electricity is the A.B.C. three-phase, phase-to-phase voltage is 380V, and two-phase electricity is the voltage of phase line and neutral line is 220V. Two-phase electricity is two wires, one is fire and the other is zero, which corresponds to ordinary 220 V.
Three-phase electricity is used by users with relatively high energy consumption. Take any phase and a zero is 220V, take any 2 phase is 380V. It should be distinguished according to the label of the electrical appliance. .
General house access lines have a total power supply of 220 V, but some buildings also have a three-phase junction box, designed by designers inconsidering that users can use it.
The difference between three-phase power and two-phase power: The power generated by the generator is three-phase. Each phase of the three-phase power supply and its neutral point can form a single phase. -phase loop to provide energy to users.
Note that in the AC circuit here, it cannot be called the positive pole or the negative pole. It should be called the end of the line (called the live wire in civil electricity) and the neutral line (called the neutral line). neutral line in civil electricity).
References:
Principle of converting three-phase electricity into two-phase electricity
Generally, three-phase 380V voltage and single-phase 220V voltage are used. If there is three-phase electricity and a neutral line, then any combinationison of phase line and neutral line can obtain single-phase 220V electricity.
Three-phase alternating current is a form of electrical energy transmission, called three-phase power. Three-phase AC power is a power supply consisting of three AC potentials with the same frequency, amplitude and phase differences of 120° from each other.
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This takes into account the performance of the leak protector function. (The working principle of leakage protector: If a human body touches the end of the power supply, that is, the live wire, or if there is a leak inside electrical equipment, then the current flows through the live wire If the human body or the shell of the electrical equipment flows into the earth instead of through the neutral wire, the currents in the live wire and. the neutral wire will be uneven. The leakage protector will trip immediately after detecting this current difference to protect the safety of people and electrical appliances. Generally, this differential current selection at tens of mA).
Ifhe neutral point of the power supply is directly grounded (this is not allowed in civil electrical construction), the leakage protector will lose its function and cannot protect people and electrical equipment from short-circuits. circuits.
In three-phase electricity, the voltage between the lines is 380 volts, and the voltage between each phase of three-phase electricity and the neutral line (earth) is 220. Volts.
Three-phase electricity cannot be converted to two-phase electricity. Many people mistakenly believe that two-phase electricity has two wires. In the motor, three-phase power supply is used at the same time, but the voltage is different from the wiring used. The delta connection uses 220 volts and the star connection uses 380 volts.
The electrical appliances that we usually use at home also use 220 volts, which are entered through two wires and are myophased. But why can the engine run? Is it because there is a large capacitor inside the electrical circuit? Appliance, after one phase of electricity enters, part of the current is divided into two phases through a large capacitor, and the household appliance can work with two phases. ?
Phase electricity is usually 380 volts, with four wires, three of which are live wires and one is a neutral wire; 380 volt electricity is used for industrial electricity.
Two-phase electricity is generally 220 volts, with two wires, one of which is the live wire and the other is the neutral wire. 220 volt electricity is used for civil electricity or small machines.
According to regulations, the neutral point of a 380 volt civil power supply (three-phase) must not be grounded at the input (grounded at the end of the transformer. This grounding is taken into accountaccount so as not to cause high voltage due to floating points. Depending on the supply voltage point, there is some resistance in the ground between the user side ground and the transformer side ground).
The power supply method is a live wire and a neutral wire (neutral point lead wire) forming a loop, and a ground wire is also connected to the single-phase three-conductor power socket . This takes into account the achievement of the function of the leak protector. (The working principle of the leakage protector is: if a human body touches the end of the power supply, that is, the live wire, or if there is a leak at the 'inside the electrical equipment.
At this time, the current flows from the live wire If it flows into the earth through the human body or the shell of the electrical equipment without passing through. the neutral wire, the currentss in the live wire and neutral wire will be uneven, and the leakage protectorAfter detecting this current difference, it will trip immediately to protect the safety of people and electrical appliances. Typically, this differential current is chosen to be several tens of milliamps.) If the neutral point of the power supply is directly grounded (this is not allowed). civil electrical construction), the leakage protector loses its function and cannot protect people and electrical equipment from short circuits.