Page 234 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

because due to heavy traffic in big cities, the vehicle cannot be driven at high speed. The dynamo is unable to
charge the battery properly at low speeds of the vehicle.
Alternator, which is AC. There is a generator, so it is D.C. AC instead of current. Produces current, which is again
converted into DC. The battery is charged by converting. The weight of alternator is less than that of dynamo. It
does not have commutator, carbon bush and armature winding etc.
Hence copper is saved. It produces relatively high current even at low engine speed. It requires less care. A small
regulator is used with it, because the diodes used in it only allow the current to flow in one direction and do not
allow it to come back, due to which there is no need to install a cut-out coil.

As shown in the picture, it consists of an armature magnet with insulated copper wire wound on it. In this, the north
pole of the magnet is at the top and the south pole is at the bottom.
When the armature magnet is rotated, an electric force is generated in the wires in half of its revolution, the
direction of which is one way. After this the position of the magnetic poles changes to opposite. In the forward half
of the movement of the amateur magnet, the current flows in the other direction. Thus, current flows on both sides
in one turn of the armature magnet, hence it is called alternating current (AC).

Importance of checking charging circuit for proper
functioning

Objectives: At the end of this lesson you shall be able to
• explain Importance of checking charging circuit for proper functioning.

Charging System
Introduction
Electronic devices used in automotive vehicles; For example, horn, light, indicator etc. require a direct current
energy source and the best source for obtaining pure direct current is the battery. Battery is basically a group of
chemical cells, in which electrical energy is obtained through the electromotive force (emf) generated as a result
of chemical reaction. This can be termed as a reliable device. All batteries, once charged, get discharged after
some time when used.
Therefore, the process done to recharge them is called charging system. of charging system

It has two essential functions - one is to produce electrical power to operate the vehicle’s electrical system and
the other is to produce current to recharge the battery installed in the vehicle. In these, electrical power means
the power which is provided to the vehicle as per its requirement at low engine speeds. At high engine speeds the
charging system meets all the vehicle’s electrical needs. The charging components mainly include alternators. In
the present chapter, a detailed description of the charging system and its components has been given.

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CITS : Automotive - Mechanic Diesel - Lesson 67 - 70