The standard of the national civil grid in the United States is 110 volts at 50 Hz, and the standard in China is 220 volts at 50 Hz. There are also countries with 55 Hz and 60 Hz, and the voltage is different!
Specifically, there are several reasons why the voltage standards of household grids in the world are inconsistent.
China’s power grid is a three-phase four-wire system with a frequency of 50 Hz, a phase voltage of 220 volts and a line voltage of 380 volts. The US phase voltage is 110 volts at 60 Hz. Compared with electrical equipment of the same power, China’s cost is low, the transmission distance is small, the cross-sectional area of the wire is reduced by half, and the motor power-to-volume ratio is small, saving motor manufacturing materials and reducing production costs.
As for why it is not unified, it is because there are already so many electrical appliances that use this voltage, and all the original electrical appliances will not be able to be used if they are replaced. No one wants to bear the cost. For electrical appliance manufacturers, most appliances do not move, so as long as the power supply or power is designed according to the national standard, the marginal cost of this part is infinitely close to zero for large-scale production. . For mobile appliances like notebooks, it is enough to use a power adapter that is suitable for all voltages and frequencies in the world, and it also ensures the stability of the power supply used by the notebook.
Because the actual situation of each country is different, the advanced level of development is not the same, the popularization of electrification in Europe and the United States is relatively early, and the developing countries are relatively lagging behind. Therefore, those who lag will refer to the standards of developed countries. Some developed countries consider safety and lower voltage, while others choose higher voltage considering line costs. The 110-volt U.S. voltage is influenced by the history of Edison’s recommendation. Edison recommended 110-volt voltage, so there are more and more 110-volt electrical appliances. Low voltage really wastes materials such as wires, but the voltage is not easy to change, because the power system continues to 110v, change The electrical appliances of the common people have become obsolete, so it has been continued. The country started late. Considering the energy saving and cost reduction, of course, high voltage 220v is used. The frequency is 50Hz because considering the country’s vast territory and low frequency is good for long-distance power transmission.
Because the time when countries in the world have electricity is not uniform. Some have electricity earlier, some later. And these power stations are also built by different countries. The standard of voltage transmission varies from country to country (because different voltage performance has advantages and disadvantages). However, there are only a few main power transmission and transformation voltages in the world, and there are not many, and the voltages can be converted to each other through technology. There will be no impact on users.