Alternating current refers to the current that changes periodically at any time and direction, and the average current in a period is zero. Unlike direct current, its direction changes with time, while direct current does not change periodically.
Usually, the waveform of alternating current is sinusoidal. Alternating current can effectively transmit electricity. But there are actually other waveforms, such as triangle wave and square wave. The commercial power used in life is sine wave alternating current.
When electromagnetic induction was discovered, the method of generating alternating current was known. The early generators were invented by michael faraday, an Englishman, and Puzhengsu Percy, a Frenchman.
1882, British electrician James Gordon built a large two-phase alternator. Lord Kelvin and Sebastian ziani de Ferranti developed early alternators with frequencies ranging from 100 Hz to 300 Hz.
189 1 year, nikola tesla obtained the patent of high frequency alternator (15000Hz). 189 1 year later, power supply will be provided by multiphase alternator. Thereafter, the AC frequency of the alternator is usually designed between 16 Hz and 100 Hz, and it is used in conjunction with arc lamps, incandescent lamps or motors.
According to the law of electromagnetic induction, when the magnetic field around a conductor changes, an induced current will be generated in the conductor. Usually, the rotating magnet is called rotor, and the fixed group in the coil with conductor wound on the iron core is called stator. When it passes through a magnetic field, it generates an electric current. The basic machine that generates alternating current is called alternator. ?