Which frequency is commonly used on distribution systems in countries other than the United States?

The choice of 50 Hz for frequency in distribution systems, particularly in countries outside the United States, is rooted in historical and engineering decisions made during the early developments of electrical systems. Many countries, especially in Europe, Asia, Africa, and Australia, adopted 50 Hz as their standard frequency. This frequency was largely influenced by the early designs and the equipment available at the time.

Using a frequency of 50 Hz offers certain advantages in terms of energy transmission efficiency and equipment design. Power transformers and motors designed to operate at 50 Hz generally have a specific physical size and weight characteristics that can be optimized for this frequency. This results in more efficient operation of electrical devices and systems across varying loads.

In contrast, 60 Hz, which is the standard in the United States and a few other countries, became prominent because of the early choices made by some electrical pioneers in North America. It has since remained the standard there due to the vast infrastructure already in place.

Choosing a frequency such as 40 Hz or 70 Hz is less common because those frequencies do not have the same level of historical adoption or compatibility with existing electrical devices and systems. Most equipment and appliances are designed to operate at either 50 Hz or 60 Hz, which supports why