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A permanent magnet synchronous generator is a generator where the excitation field is provided by a permanent magnet instead of a coil. The term synchronous refers here to the fact that the rotor and magnetic field rotate with the same speed, because the magnetic field is generated through a shaft-mounted permanent magnet mechanism, and current is induced into the stationary armature.
Diagram of a disk MHD generator showing current flows. The third and, currently, the most efficient design is the Hall effect disc generator. This design currently holds the efficiency and energy density records for MHD generation. A disc generator has fluid flowing between the center of a disc, and a duct wrapped around the edge.
Commutator of the Woolrich Electrical Generator. The first electrical machine used for an industrial process was a magneto, the Woolrich Electrical Generator. [3] In 1842 John Stephen Woolrich was granted UK patent 9431 for the use of an electrical generator in electroplating, rather than batteries.
The rotating magnetic field is the key principle in the operation of induction machines.The induction motor consists of a stator and rotor.In the stator a group of fixed windings are so arranged that a two phase current, for example, produces a magnetic field which rotates at an angular velocity determined by the frequency of the alternating current.
The magnetic field of the dynamo or alternator can be provided by either wire windings called field coils or permanent magnets. Electrically-excited generators include an excitation system to produce the field flux. A generator using permanent magnets (PMs) is sometimes called a magneto, or a permanent magnet synchronous generator (PMSG).
An electric generator or electric motor consists of a rotor spinning in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils . In the case of a machine with field coils, a current must flow in the coils to generate ( excite ) the field, otherwise no power is transferred to or from the rotor.
Magnetic field (green) induced by a current-carrying wire winding (red) in a magnetic circuit consisting of an iron core C forming a closed loop with two air gaps G in it. In an analogy to an electric circuit, the winding acts analogously to an electric battery, providing the magnetizing field , the core pieces act like wires, and the gaps G act like resistors.
Cancellation of magnetic components resulting in a one-sided flux. Although this magnetic flux distribution seems somewhat counter-intuitive to those familiar with simple bar magnets or solenoids, the reason for this flux distribution can be intuitively visualised using Mallinson's original diagram (note that it uses the negative y component, unlike the diagram in Mallinson's article).