SIMPLE AC GENERATOR

AMIT KUMARSHRUTI PRIYA

AAKARSH KUNWERFRANCIS HARSHIT

AC GENERATOR

• It is also called dynamo or alternator.• It converts one form of energy into another

form ,i.e, Mechanical to Electrical energy.• It operates through the interaction between a

magnetic field & coil.• It is work on the principle of ELECTROMAGNETIC

INDUCTION

Principle

• The working of an A.C. generator is based on the principle of "electromagnetic inducion".

• When a coil is rotated in a uniform magnetic field with its axis perpendicular to the magnetic field.

• The magnetic flux linked with the coil changes and an induced emf and hence a current is set up in it.

Components

• Field magnet

• Armature

• Slip rings

• Brushes

• Prime mover

Field magnet

• It is a powerful electromagnet or permanent magnet.

• It produce strong magnetic field in the region between its pole.

Armature

• It consists of a rectangular coil having a large number of turns of insulated copper wire wound on a soft iron cylinderical core.

• It can be rotated in the magnetic field of the field magnet about an axis perpendicular to field.

Slip rings• Two ends of armature coil are connected to two

coaxial brass ring called slip rings.• A slip rings are rigidly fixed to same shaft which is used to rotate the coil.• As the armature coil rotate the slip rings also rotates about the same axis of rotation

Brushes

• Two graphite or flexible metalic rods called brushes are lightly pressed against slip rings.

• Through brushes the current induced in the armature coil is fed to the external circuit by the means of line wires.

Prime mover

• The prime mover is the component that is used to drive the AC generator.

• The prime mover may be any type of rotating machine,such as diesel engine, a steam turbine, or a motor.

Working

• The ac generator uses Faraday's laws of induction, it consists of a coil of wire rotating a magnetic field. As the coil rotates it cuts the magnetic flux generating an EMF, the EMF produced is given by Faraday's law. The angle is changing at the angular frequency ω.

Working• The ac generator uses Faraday's laws of induction,

it consists of a coil of wire rotating a magnetic field. As the coil rotates it cuts the magnetic flux generating an EMF, the EMF produced is given by Faraday's law. The angle is changing at the angular frequency ω. Therefore at a given moment in time the angle between the normal to the area and the magnetic field lines will be ωt. Therefore the flux linkage, φN will be BAN cos(ωt). Differentiating cos(ωt) function with respect to time gives -ω sin(ωt).

Working• Therefore, the EMF is given by

• The electrons flow first in one direction and then, in the other. The generator produces an alternating current.

DESCRIPTION OF AN AC DYNAMO - Electric Generator 720.mp4

Application• Electric generators: Alternators are used in modern automobiles to charge the battery and to power the electrical system when its engine is

running.• Diesel electric locomotive alternators: Diesel electric locomotives and diesel electric multiple units, the prime mover turns an alternator which provides electricity for thetraction motors

Application

• Marine alternators: Marine alternators used in yachts are similar to

automotive alternators, with appropriate adaptations to the salt-water environment.