The difference between single-phase electricity, two-phase electricity, and three-phase electricity

Single-phase electricity and two-phase electricity are two different power supply methods, and there are obvious differences between them in the form and voltage of power transmission.

Single-phase electricity refers to the form of power transmission consisting of one phase line and one neutral line. The phase line, also known as the live wire, provides power to the load, while the neutral line serves as the path for the return current. The voltage of single-phase electricity is 220 volts, which is the voltage between the phase line and the neutral line.

In home and office environments, single-phase electricity is the most common type of power supply. On the other hand, two-phase power supply is a power supply circuit consisting of two phase lines, referred to as two-phase electricity. In two-phase electricity, the voltage between the phase lines is called line voltage, which is usually 380 volts.

In contrast, the voltage of single-phase electricity is the voltage between the phase line and the neutral line, which is called phase voltage. In industry and certain household appliances, such as welding machines, two-phase electricity is widely used.

In summary, the main difference between single-phase electricity and two-phase electricity is the form and voltage of power transmission. Single-phase electricity consists of one phase line and one neutral line, which is suitable for home and office environments, and the voltage is 220 volts. The two-phase power supply consists of two phase lines, which is suitable for industry and certain household appliances, with a voltage of 380 volts.

Single-phase power supply: usually refers to any phase line (commonly known as live wire) + neutral line in the 380V three-phase four-wire AC power supply, the voltage is 220V, the phase line will glow when measured with an ordinary low-voltage electric pen, and the neutral line will not glow. It is the most common energy source in daily life. Single-phase is any phase line in the three phases to the neutral line. It is often called “live wire” and “neutral wire”. Usually refers to 220V, 50Hz AC. Single-phase voltage is also called “phase voltage” in electrical engineering.
Three-phase power supply: A power supply composed of three AC potentials with the same frequency, equal amplitude, and phase difference of 120 degrees is called a three-phase AC power supply. It is generated by a three-phase AC generator. The single-phase AC used in daily life is provided by one phase of the three-phase AC power supply. The single-phase AC power supply generated by a single-phase generator is rarely used.

3 single-phase watt-hour meter transformer wiring
The difference between single-phase power supply and three-phase power supply is that the power generated by the generator is three-phase, and each phase of the three-phase power supply and its neutral point can form a single-phase circuit to provide power energy for users. Simply put, three-phase electricity has three phase wires (live wires) and one neutral wire (or neutral wire), and sometimes only three phase wires are used. According to the Chinese standard, the voltage between phase wires is 380 volts AC, and the voltage between phase wires and neutral wires is 220 volts AC. Single-phase electricity has only one live wire and one neutral wire, and the voltage between them is 220 volts AC. Three-phase alternating current is a combination of three groups of single-phase alternating currents with equal amplitude, equal frequency, and 120° phase difference. Single-phase electricity is a combination of any phase wire and neutral wire in three-phase electricity.

Nan-Dou-Xing-Intelligent-Leakage Protector (Smart Power Use)
What are the advantages of comparing the two? Three-phase AC has many advantages over single-phase AC. It has obvious advantages in power generation, transmission and distribution, and conversion of electrical energy into mechanical energy. For example, the manufacture of three-phase generators and transformers saves materials compared to the manufacture of single-phase generators and transformers of the same capacity, and the structure is simple and the performance is excellent. For example, the capacity of a three-phase motor made of the same material is 50% larger than that of a single-phase motor. Under the condition of transmitting the same power, a three-phase transmission line can save 25% of non-ferrous metals compared to a single-phase transmission line, and the power loss is less than that of a single-phase transmission line.