Physics - Motors and Generators Test

Topics: Electrical generator, Alternator, Electricity Pages: 7 (2394 words) Published: March 20, 2011
The stator is the stationary part of a rotor system, found in an electric generator, electric motor and biological rotors. Depending on the configuration of a spinning electromotive device the stator may act as the field magnet, interacting with the armature to create motion, or it may act as the armature, receiving its influence from moving field coils on the rotor. The first DC generators (known as dynamos) and DC motors put the field coils on the stator, and the power generation or motive reaction coils on the rotor. This was necessary because a continuously moving power switch known as the commutator is needed to keep the field correctly aligned across the spinning rotor. The commutator must become larger and more robust as the current increases. The stator of these devices may be either a permanent magnet or an electromagnet. Where the stator is an electromagnet, the coil which energizes it is known as the field coil or field winding. DC Armature (electrical engineering)

In electrical engineering, an armature generally refers to one of the two principal electrical components of an electromechanical machine–generally in a motor or generator, but it may also mean the pole piece of a permanent magnet or electromagnet, or the moving iron part of a solenoid or relay. The other component is the field winding or field magnet. The role of the "field" component is simply to create a magnetic field (magnetic flux) for the armature to interact with, so this component can comprise either permanent magnets, or electromagnets formed by a conducting coil. The armature, in contrast, must carry current so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque (rotating machine), or force (linear machine). The armature's role is two-fold. The first is to carry current crossing the field, thus creating shaft torque in a rotating machine or force in a linear machine. The second role is to generate an electromotive force (EMF). In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine is acting as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical torque, and power, unless the machine is stalled, and transfers it to the load via the shaft. When the machine is acting as a generator, the armature EMF drives the armature current, and shaft mechanical power is converted to electrical power and transferred to the load. In an induction generator, these distinctions are blurred, since the generated power is drawn from the stator, which would normally be considered the field. Terminology

The parts of an alternator or related equipment can be expressed in either mechanical terms or electrical terms. Although distinctly separate, these two sets of terminology are frequently used interchangeably or in combinations that include one mechanical term and one electrical term. This may cause confusion when working with compound machines such as brushless alternators, or in conversation among people who are accustomed to work with differently configured machinery. In alternating current machines, the armature is usually stationary, and is known as the stator winding. In DC rotating machines other than brushless DC machines, it is usually rotating, and is known as the rotor. The pole piece of a permanent magnet or electromagnet and the moving, iron part of a solenoid, especially if the latter acts as a switch or relay, may also be referred to as armatures. Mechanical

Rotor: The rotating part of an alternator, generator, dynamo or motor. Stator: The stationary part of an alternator, generator, dynamo or motor Electrical
Armature: The power-producing component of an alternator, generator, dynamo or motor. The armature can be on either the rotor or the stator. Field: The magnetic field component of an alternator, generator, dynamo or motor. The field can be on either...
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