AC GENERATOR - DIY kit for Students

How does the electric supply get into your house? The answer to this is the AC Generator. But have you seen anac generator working? And do you know how the mechanism behind it does? Well, let us study this more in detail. An AC generator is an electricgenerator that convertsmechanical energy into electrical energyin form of alternative emf or alternating current. AC generator works on the principle of ”Electromagnetic Induction”.

The Alternating Current Generator. An electric generator, or dynamo, is a device which converts mechanical energy into electrical energy. The simplest practical generator consists of a rectangular coil rotating in a uniform magnetic field. The magnetic field is usually supplied by a permanent magnet.

PRINCIPLE:

A.C. generators or alternators (as they are usually called) operate on the same fundamental principles of electromagnetic induction as D.C. generators. the speed at which the coil or magnetic field rotates. A.C. generators or alternators (as they are usually called) operate on the same fundamental principles of electromagnetic induction as D.C. generators.

Alternating voltage may be generated by rotating a coil in the magnetic field or by rotating a magnetic field within a stationary coil. The value of the voltage generated depends on- The number of turns in the coil. Strengthof the field. The speed at which the coil or magnetic field rotates.

PARTS OF AN AC GENERATOR:

An Ac generator consists of two poles i.e is the north pole and south pole of a magnet so that we can have a uniform magnetic field. There is also a coil. The coils rotate about an axis which is perpendicular to the magneticfield. There is also a shaft which rotates rapidly. What is the difference between DC generator and AC generator? - The major difference between an AC generator and a DC generator is that the DC generator requires a mechanism to provide a DC output. This can be done mechanically with a commutator or electronically with a rectifier. Internally, all generators producean alternating voltage.All generators require a magnetic field.

[NOTE: Pulleys representsimple machines used for many operations. Pulley systems are made from two pulley wheels on a shaft with a belt joining them. One pulley is the driver pulley, and the other is the driven pulley. Pulleys can change speed, provide torque and alter rotation direction. Changing speed with pulleys entails changing the diameter of a pulley wheel.]

Your AC Generator is ready…. Activate your energy source (i.e. Spin the Pulley). As you spin the shaftas fast as possible. You should get a small voltage, enough to light a 1.5 volt LED by manually spinning the shaft The LED will glow. You've just produced electricity

HOW IT WORKS: Instead of fixing the magnet and rotating the coil in a simple AC generator, a fixed coil generator is made by fixing the coil and rotating the magnet. A bicycle dynamo is an example of this as shown below. At most time, fixed coil generator is preferred due to following reasons:

It is more compact; It does not require carbon

brushes and slip rings; As the connection between carbon brushes and slip rings would become loose when carbon brushes wear and tear, this increases the resistance and hence the amount of heat generated. Therefore, without carbon brushes,it is less likely to break down from overheating. As the magnets are rotating clockwise, when coil is horizontal, by Fleming’s Right Hand Rule, the induced current will flow.

WORKING OF AN AC GENERATOR: When the armature rotates between the poles of the magnet upon an axis perpendicular to the magnetic field, the flux which links with the armature changes continuously. Due to this, an emf is induced in the armature. This produces an electric current through the galvanometer and the slip

rings and brushes. The galvanometer swings between the positive and negative values. This indicates that there is an alternating current flowing through the galvanometer.

What is an AC generator and how does it work? : An AC generator or an Alternator works on fara days law of electromagnetic induction, which states that when a conductor is rotated in a magnetic field, an emf is

induced in it. An Alternator has 2 sets of windings, namely main field findings and exciter windings. The exciter field winding is supplied with DC. In a dynamo, a split ring commutator changes the coil connections every half turn. As the induced potential difference is about to change direction, the connections are reversed.This means that the current to the external always in the same direction.