Electrical Frequency

Frequency, Electrical


the time parameter of a periodically (cyclically) varying electric current, expressed by the ratio of the number of complete cycles of current variation to unit of time; the quantity is the inverse of the period of current variation. It is measured in hertz (Hz). For a sinusoidal alternating current the concept of angular frequency is used, which is related to the electrical frequency by the formula ω = 2πf (where ω is the angular frequency and f is the electrical frequency).

In many countries of the world, including the USSR, the frequency of the current generated by electric power stations and commercially distributed to industry is 50 Hz; in the USA it is 60 Hz. Railroads in many countries use current with a frequency of 16⅔ Hz (for electric traction) as well as frequencies of 25 and 75 Hz (for automatic block signaling, for example, on track circuits). In aviation, the current used has a frequency of 400 Hz (for independent power-supply systems). In certain industrial and agricultural equipment the operating frequency is raised to 200–400 Hz.

References in periodicals archive ?
23, 2015 /PRNewswire/ -- About DC drives A drive is an adjustable device that regulates the speed and torque of motors by varying electrical frequency and voltage.
6 cycles per second, which is close to a key electrical frequency in the brain.
In The Theory of Homogeneous Turbulence, 2002, metaphor came true in a nighttime winter installation in the woods at the Villa di Medici in Rome (at Chiara Parisi's invitation): Assael hid three powerful fans behind bushes; a white light rotated and flashed high in the trees while its electrical frequency was miked and amplified.
The controller senses electrical frequency and functions as an automatic on/off switch for stand-alone pumps.
The engines can also be operated at their optimal speed for peak efficiency and lowest emissions while generating power at an electrical frequency selected by the operator.
Moreover, the electrical frequency will be adjustable and the voltage can be modulated at the grid connection point to accommodate any sudden fluctuations in solar intensity.
Independently of any electrical frequency, users can call on a maximum power of 3,440 kWmec at 2,100 rpm.