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Why is alternating voltage induced in the rotating armature of a generator?
Wiki User
∙ 12y ago
The windings of the armature are constantly cutting magnetic lines of force of opposite polarities
Wiki User
∙ 12y ago
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Operation of DC generator?
1) PRINCIPLE:Whenever a conductor cuts magnetic flux, dynamically induced emf is produced in it. ( Faraday's Laws of Electromagnetic Induction ). This emf causes a current to flow if the conductor circuit is closed.2 ) OPERATION:Field winding produces magnetic field in D.C. generator. Armature is coupled to the prime mover. Prime mover produces torque so the armature rotates. The armature cuts the magnetic field so the emf is induced in the armature. When load is connected to the armature, electric current flows from the armature conductors, through load and back to the armature conductors. Now, as current flows through the armature and it is in the magnetic field, torque is produced due to it. (This torque is called back torque). If the load on the generator is increased, the back torque increases so the torque of the prime mover also increases and the input power to the prime mover increases. In this way, the generator converts mechanical energy into electrical energy.It should be observed that the emf induced in D.C. generator, is A.C. ( so the emf induced in the armature is alternating in nature. ). Then with the help of commutator, it is converted into D.C. Rings and brushes are used to take the emf outside.
Why the induction motor does not have armature reaction?
Because the armature (or rotor) has no external connection. The currents that produce torque from the rotor are induced by the magnetic field in the machine, so there is no commutator, no brushes and no armature reaction.
Difference between statically and dynamically induced emf?
STATICALLY INDUCED EMFThe emf induced in a coil due to change of flux linked with it (change of flux is by the increase or decrease in current) is called statically induced emf.Transformer is an example of statically induced emf. Here the windings are stationary,magnetic field is moving around the conductor and produces the emf.DYNAMICALLY INDUCED EMFThe emf induced in a coil due to relative motion of the conductor and the magnetic field is called dynamically induced emf.example:dc generator works on the principle of dynamically induced emf in the conductors which are housed in a revolving armature lying within magnetic field
What makes the armature in the electric motor rotate?
from Faraday's law of electromagnetic induction : when a current carrying conductor cuts the magnetic field an E.M.F (electro motive force) is produced and it sets up in such a direction so as to oppose the cause of it. the stator winding of a motor which produces the R.M.F (rotating magnetic field) serves as the magnetic field and the armature winding is the current carrying conductor which cuts the magnetic field , thus an EMF is induced in the armature which again produces a force to oppose the emf produced in the armature winding.
What is the purpose of commutator in a dc generator?
Commutators are used to get unidirectional current Flow through the external circuits in DC generator system.A commutator is an electrical switch that periodically reverses the current direction in an electric motor or electrical generator.
How the generator and motor works ALTERNATING CURRENT GENERATORS BASIC AC GENERATORS Regardless of size all electrical generators whether dc or ac depend upon the principle of magneticinduction.?
An emf is induced in a coil as a result of (1) a coil cutting through a magnetic field, or (2) a magnetic field cutting through a coil. As long as there is relative motion between a conductor and amagnetic field, a voltage will be induced in the conductor. That part of a generator that produces the magnetic field is called the field. That part in which the voltage is induced is called the armature. Forrelative motion to take place between the conductor and the magnetic field, all generators must have two mechanical parts - a rotor and a stator. The ROTor is the part that ROTates; the STATor is the part that remains STATionary. In a dc generator, the armature is always the rotor. In alternators, the armature may be either the rotor or stator. ROTATING-ARMATURE ALTERNATORSThe rotating-armature alternator is similar in construction to the dc generator in that the armature rotates in a stationary magnetic field as shown in figure 3-1, view A. In the dc generator, the emf generated in the armature windings is converted from ac to dc by means of the commutator. In the alternator, the generated ac is brought to the load unchanged by means of slip rings. The rotating armature is found only in alternators of low power rating and generally is not used to supply electric power in large quantities.
Operation of DC generator?
1) PRINCIPLE:Whenever a conductor cuts magnetic flux, dynamically induced emf is produced in it. ( Faraday's Laws of Electromagnetic Induction ). This emf causes a current to flow if the conductor circuit is closed.2 ) OPERATION:Field winding produces magnetic field in D.C. generator. Armature is coupled to the prime mover. Prime mover produces torque so the armature rotates. The armature cuts the magnetic field so the emf is induced in the armature. When load is connected to the armature, electric current flows from the armature conductors, through load and back to the armature conductors. Now, as current flows through the armature and it is in the magnetic field, torque is produced due to it. (This torque is called back torque). If the load on the generator is increased, the back torque increases so the torque of the prime mover also increases and the input power to the prime mover increases. In this way, the generator converts mechanical energy into electrical energy.It should be observed that the emf induced in D.C. generator, is A.C. ( so the emf induced in the armature is alternating in nature. ). Then with the help of commutator, it is converted into D.C. Rings and brushes are used to take the emf outside.
What is alternating current normally produced by?
Alternating current is normally produced by rotating the magnet in the coil of an induced alternating voltage. When connected to a circuit, an alternating current will flow.
How is alternating current produced in a generator?
In an AC generator an armature is rotated in a magnetic field. This induces an electric current in the armature. if you want more look on the bottom. As the crank turns the armature rotates in the magnetic field. One side of the armature moves up, and the other side moves down. The up and down motion induces a current in the wire. The current is in opposite directions on two sides of the armature. After the armature turns halfway, each side of it reverses direction in the magnetic field. The side that moved up moves down, vice versa. The current is induced. As the Armature turns, slip rings turn with it. They are attached to the ends of the armature. As they turn, they make contact with the brushes. The brushes can be connected to the rest of the circuit. In this way, a generator becomes energy source.
What is armature current according to generator terms?
Generator is a machine which converts mechanical energy into electrical energy.For conversion of mechanical energy in to electrical energy, it uses electromagnetic induction principle.For electromagnetic induction to happen, three things are required.These are:Magnetic fieldConductorMotionSo, when the conductor starts rotating through the magnetic field or the magnetic field cuts the conductor, emf( electromotive force) or voltage is induced in the conductor.So, the conductor in which the voltage is induced in it is known as armature
Why the induction motor does not have armature reaction?
Because the armature (or rotor) has no external connection. The currents that produce torque from the rotor are induced by the magnetic field in the machine, so there is no commutator, no brushes and no armature reaction.
How does a small generator produce current?
It doesn't! It produces voltage. It does this by the relative movement between an armature (winding into which a voltage is induced) and a magnetic field (set up by field windings). Either the armature rotates inside a fixed field (small generators) or the field rotates within a fixed armature (larger generators).Current is only supplied when a load is connected to the generator.
What are the parts of an generator?
There is no such thing as an AC generator, if it's DC it's a generator, if it's AC, it's an alternator.CommentThe above answer isn't correct, as 'generator' is a generic term applied to both d.c. and a.c. machines. It is perfectly correct to use the terms 'd.c. generator' or 'a.c. generator'. It is also correct to call an a.c. generator an 'alternator'.To answer the question, an a.c. generator can be broken down into two main parts: the 'stator' (stationary part) and the 'rotor' (rotating part). The field winding is part of the rotor assembly, and the armature windings (the windings into which the generated voltages are induced) are part of the stator assembly.
Working of DC generator?
dc generator is mechanical energy into convert electrical energy which used in machine part of stator in a out part & rioter is inner part and voltage induced armature winding and current pass is Field winding it is magnetic flux generate
Can emf induced without an alternating magnetic flux?
No. EMF can only be induced in a wire by a varying magnetic flux. It does not have to be alternating, but it must be varying.
What are field windings and armature windings in a dc motor and generator?
generators have two types of winding , * at armature also called armature winding( winding around shaft , we can say), which is the moving part. note that armature also consists of magnets along with windings. hence produces field arount it. * and at stator also called field winding, because when armature rotates its flux(field) is cutted by the stator windings and produces mutually induced e.m.f in it( in stator windings off course) causing current to flow. this current also produces some electric field around it which is in return cutted by the armature windings hince a little amount of e.m.f ( also called back e.m.f) produced in armature due to stator winding current. know this current in armature (due to back e.m.f produced by stator winding) produces additional field , hence causing more current in stator winding. this is the reason that why stator windings are called field winding( as they cause electric field of armature stronger and cause more current in output). note that out put is taken from the stator windings in generators.
What is back motor effect in generator?
When current is induced in the rotating coil in an electric generator then a counter couple acts on the current carrying rotating coil in the magnetic field(in accordance to the principle of dc motor). This counter couple is called back motor effect.
