A rotating magnetic field is the resultant magnetic field produced by a system of coils symmetrically placed and supplied with polyphase currents. A rotating magnetic field can be produced by a poly-phase (two or more phases) current or by a single phase current provided that, in the latter case, two field windings are supplied and are so designed that the two resulting magnetic fields generated thereby are out of phase.
Rotating magnetic fields are often utilized for electromechanical applications, such as induction motors, electric generators and induction regulators.
In 1824, the French physicist François Arago formulated the existence of rotating magnetic fields using a rotating copper disk and a needle, termed “Arago's rotations.” English experimenters Charles Babbage and John Herschel found they could induce rotation in Arago's copper disk by spinning a horseshoe magnet under it, with English scientist Michael Faraday later attributing the effect to electromagnetic induction. In 1879, English physicist Walter Baily replaced the horseshoe magnets with four electromagnets and, by manually turning switches on and off, demonstrated a primitive induction motor.
The idea of a rotating magnetic field in an AC motor was explored by the Italian physicist and electrical engineer Galileo Ferraris and the Serbian-American inventor and electrical engineer Nikola Tesla. Ferraris wrote about researching the concept and built a working model in 1885. Tesla attempted several (unsuccessful) designs and working models through the early 1880s before building a working prototype in 1887 According to Ferraris principle of rotating magnetic field, Friedrich August Haselwander developed the first AC 3 phase generator in 1887. In 1888, Ferraris published his research in a paper to the Royal Academy of Sciences in Turin and Tesla obtained a United States patent () for his design. Based on the Haselwander generator, Mikhail Dolivo-Dobrovolsky will develop a three-phase generator and motor for the world's first three-phase power plant built in 1891 in Frankfurt, Germany.
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Le cours aborde les principales méthodes pour l'analyse de systèmes électromécaniques. Une étude des grandeurs physiques magnétiques est suivie par la conversion de l'énergie électrique en énergie méc
A polyphase system is a means of distributing alternating-current (AC) electrical power where the power transfer is constant during each electrical cycle. AC phase refers to the phase offset value (in degrees) between AC in multiple conducting wires; phases may also refer to the corresponding terminals and conductors, as in color codes. Polyphase systems have three or more energized electrical conductors carrying alternating currents with a defined phase between the voltage waves in each conductor; for three-phase voltage, the phase angle is 120° or 2π/3 radians (although early systems used 4 wire two-phase).
An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor can therefore be made without electrical connections to the rotor. An induction motor's rotor can be either wound type or squirrel-cage type. Three-phase squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable, and economical.
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc lamp street lighting running on high-voltage alternating current (AC), and large-scale low-voltage direct current (DC) indoor incandescent lighting being marketed by Thomas Edison's company.
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Magnetic nanorods driven by rotating fields in water can be rapidly steered along any direction while generating strong and localized hydrodynamic flow fields. Here we show that, when raising the frequency of the rotating field, these nanopropellers underg ...
In this work, isogeometric mortaring is used for the simulation of a six-pole permanent magnet synchronous machine. Isogeometric mortaring is especially well suited for the efficient computation of rotating electric machines, as it allows for an exact geom ...