Motors and generators, are a group of devices that are used to convert mechanical energy into electrical energy or vice versa, with electromagnetic means. A machine that converts mechanical energy into electricity is called a generator, alternator or dynamo, and a machine that converts electrical energy into mechanical engine is called.
Two interrelated physical principles underlying the operation of generators and motors. The first is the principle of induction discovered by British scientist and inventor Michael Faraday in 1831. If a conductor moves through a magnetic field, or if located in the vicinity of a fixed driving circuit can vary the intensity of which is established or induce a current in the conductor. The opposite of this principle was observed in 1820 by French physicist André Marie Ampère. If a current passed through a conductor in a magnetic field, the mechanical force exerted on the driver.
dynamoelectric machine is the simplest disk dynamo developed by Faraday, which is a copper disk that is mounted so that the disc that lies between the and the edge is located between the poles of a horseshoe magnet. When the disc spins, induces a current between the center of the disk and its edge due to the action of the magnet field. The disc can be made to function as an engine by applying a voltage between the edge and center of the disk, which makes the disk to rotate by the force produced by magnetic reaction.
The magnetic field of a permanent magnet is strong enough to power a small dynamo or motor alone. Therefore, the electromagnets are used in large machines. Both motors and generators have two basic units: the magnetic field, which is the electromagnet with its coils, and the armature, which is the structure that supports the conductors which cut the magnetic field and carries the current induced in a generator, or excitation current in the case of the engine. The armor is usually a laminated soft iron core around which coils are wound in the leads.
DC GENERATORS GENERATORS
DC generators are machines that produce stress function decreases whenever the rotating coil principle within a field magnetico.Si an armature rotates between two fixed magnetic poles the armature current flowing in a direction during half of each revolution, and in the other direction while the other half. To produce a steady flow of current in one direction, or DC, in a particular device, you must have a means to reverse the current flow outside the generator once during each revolution.
In older machines this investment was carried out by a switch, a metal ring mounted split on an armature shaft. The two halves of the ring is isolated from one another and served as terminals of the coil. The fixed metal brushes or coal were in contact with the switch, electrically connected to the rotating coil to external cables. When the armature rotated, each brush was in contact alternately with the halves of the switch, changing the position at the time in which current reversed its direction in the armature coil. This produced a current flow is a sense in the external circuit to which the generator was connected. DC generators normally operate at voltages low enough to prevent a spark produced between brushes and commutator to high voltages. The highest potential developed for this type of generator is usually 1,500 volts. In some modern machines this reversal is accomplished using power electronic devices such as rectifiers diode.
modern generators use armatures current drum, which usually consist of a large number of coils grouped into longitudinal grooves in the armature core and connected to the appropriate segments of a series switch. If an armor has only one cable circuit, the current rise and fall occurs depending on the magnetic field through which the circuit is moving. A multi-segment switch used with a drum armature always connect an external circuit to a cable that moves through an area of \u200b\u200bhigh field intensity, and as a result the current supplied coils armor is almost constant. The fields of modern generators are equipped with four or more electromagnetic poles to increase the size and strength of the magnetic field. In some cases, smaller interpoles added to compensate for distortions caused by the magnetic effect of the reinforcement in the power flow of the field.
A dynamo is a machine that produces electrical power as DC exploiting the phenomenon of electromagnetic induction. To do so is provided with a fixed frame (stator) in charge of creating the magnetic field inside which rotates a cylinder (rotor) which will create the induced electromotive forces.
Stator: consists of an electromagnet in charge of creating the fixed magnetic field by the name of inductor.
Rotor: is a cylinder which are wound copper coils, which is rotated at a certain speed and stopping the flow inducer is called induced.
operatre PRINCIPLE:
Spinning a loop in a magnetic field produces an induced emf in their drivers. The tension obtained abroad through a slip ring and brush at each end of the loop is sinusoidal character.
Connecting the ends of the loop about insulated ring halves together, we will make each brush is in contact with the armature that has a certain polarity.
During a gives the same half-period alternating voltage, but in the next half period, the connection is reversed by converting the negative into a positive half cycle.
The armature usually has many more turns and slip ring is divided into a greater number of parts or thin, isolated from one another, forming what is called the collector.
The brushes are graphite or pure carbon brush holder mounted by a spring which ensures a good contact.
By increasing the number of thin, the voltage obtained has a ripple moving closer to the DC voltage that is desired.
