Electromagnet used to generate a magnetic field in an electro-magnetic machine
A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. It consists of a coil of wire through which a current flows.
In a rotating machine, the field coils are wound on an iron magnetic core which guides the magnetic field lines. The magnetic core is in two parts; a stator which is stationary, and a rotor, which rotates within it. The magnetic field lines pass in a continuous loop or magnetic circuit from the stator through the rotor and back through the stator again. The field coils may be on the stator or on the rotor.
The magnetic path is characterized by poles, locations at equal angles around the rotor at which the magnetic field lines pass from stator to rotor or vice versa. The stator (and rotor) are classified by the number of poles they have. Most arrangements use one field coil per pole. Some older or simpler arrangements use a single field coil with a pole at each end.
Although field coils are most commonly found in rotating machines, they are also used, although not always with the same terminology, in many other electromagnetic machines. These include simple electromagnets through to complex lab instruments such as mass spectrometers and NMR machines. Field coils were once widely used in loudspeakers before the general availability of lightweight permanent magnets.
A fieldcoil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor...
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possible for the coil to hold a greatly increased amount of energy in its electric field, and lowers the resonant frequency of the coil drastically. Some...
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fed into the rotating fieldcoils through the voltage regulator (VR). This increases the magnetic field around the fieldcoils which induces a greater...
as its stator to create its magnetic field. It is a commutated series-wound motor where the stator's fieldcoils are connected in series with the rotor...
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applications. A coil of wire with a current running through it generates an electromagnetic field aligned with the center of the coil. The direction and...
on either the rotor or the stator, depending on the design, with the fieldcoil or magnet on the other part. Before the connection between magnetism and...
machine" employed self-powering electromagnetic fieldcoils rather than permanent magnets to create the stator field.[citation needed] Wheatstone's design was...
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basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the...
this instrument a stationary fieldcoil produces a rotating magnetic field, just like a polyphase motor. The fieldcoils are connected either directly...
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