Product focus
S. ganci
A Wimshurst influence machine: an electrostatic generator developed between 1880 and 1883 by British inventor James Wimshurst.
Thomas Phillips
Michael Faraday, by Thomas Phillips( oil on canvas, 1841 – 1842, 908mm × 711mm).
Awesome Stories
Hauksbee electrostatic generator, ca 1705.
The Van de Graaff generator uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, producing very high voltage direct current( DC) electricity at low current levels. It was developed at MIT in the early part of the 20th century, with the first model being demonstrated in October 1929, and in 1931, a version that could produce 1 000 000 volts was described in a patent disclosure.
Michael Faraday and beyond
The foundation for building electric motors was laid with the invention of the battery by Allessandro Volta in 1800, the generation of a magnetic field from an electric current by Hans Christian Oersted in 1820, and the invention of the electromagnet by William Sturgeon in 1825. Nearly 200 years after Guericke created the first electrostatic generator, British scientist
Michael Faraday built the first electric generator, comprising a tube of neutral material wound with a cotton-insulated coil of wire and a bar magnet. Connecting his apparatus to an instrument that detects electrical current, Faraday discovered that on passing the magnet back and forth through the stationary coil of wire, the instrument registered a current flowing.
Faraday was responsible for building the first electromagnetic generator, the Faraday disc( homopolar generator): a copper disc rotating between the poles of a horseshoe magnet and which produced a small DC voltage. This same method is used today, with the movement of a copper disc, or wire loop, between the poles of a magnet generating electricity. Long after the original Faraday disc had been abandoned as a practical generator, a modified version combining the magnet and disc in a single rotating part, or rotor, was developed.
Faraday’ s law
Faraday’ s contribution goes beyond the invention of the electric generator. Faraday’ s law of induction is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force. It summarises the ways in which a voltage( or electromotive force [ emf ]) can be generated by a changing magnetic environment; formulating that emf produced around a closed path is proportional to the rate of change of the magnetic flux through any surface bounded by that path. He would later use these principles to construct the electric dynamo. Even today, almost all electric power, regardless of primary source, is produced using Faraday’ s principles with the fuel driving a generator( or turbine) that then generates the electrical current.
32
SEPTEMBER 2017