Project - Analysis of a practical automotive wiring circuit

1) The major elements in the above given diagrm are:

• battery
• generator
• starter
• current and voltage regulator
• distributer
• breaker
• ignition coil
• fuse
• foot selection switch
• ammeter

2)

BATTERY:

Purpose:

It convertrs chemical energy into electrical energy. The chemical reactions in the battery causes flow of electrons between electrodes which can be used to operate electrical devices in a car depending upon the nature of the car(just starters or drive a car in hybrid vehicles etc.)

Working:

It contains two elctrode of different metals or compounds and an conductive medium known as electrolyte. Battery operates through electrochemical reactions known as oxidation and reduction. Oxidation is a process in which an element loses one or more electron (which occurs at the anode) and Reduction is a process in which the element gains one or more electron (which occurs at the cathode).

The electrons flow from anode to cathode when they are connected through a conducting wire. This is the source of the electricity in a battery. Now if we need to operate an electrical device we just connect it to the anode and cathode end of the battery through a wire and the current starts to flow and the device starts working (it depends on the power rating of the battery and the device, preferably it should be equal).

GENERATOR:

Purpose:

It converts the mechancal energy from the engine to the electrical energy which is either used to directly operate a vehicle or charge a battery for further uses.

Working: It converts the rotational motion of electromagnets or permanent magnets in an electromagnetic field to generate electric current. There are two parts in a generator - rotor and stator. Stator in a generator can be permanent magnet which provides the electromagnetic field. Rotor is basically coils of electrical wires, generally copper wire tightly wound around a metal core of the rotor. The rotor rotates and converts the rotational kinetic energy into electrical energy.

IGNITION COIL:

Purpose:

It converts the vehicles low voltage supply to high voltage supply in the spark plug to ignite the fuel-air mixture in the engine.

Working:

It is basically a trasnsformer which converts low voltage power to high voltage power. It consists of a laminated iron core surrounded by two coils of copper wire. An ignition coil has an open magnetic circuit, it means iron core doesnot form a closed loop aoung the windings as in a normal transformer. Theenergy transferred to the spark plug is the energy that is stored in the magnetic field in the coil.

3) Total load = 10 A

Power = V. I

= 12 * 10 W

=120 W

THe fuse rating is generally 25 percent more than the actual power rating.

Hence, power for fuse rating= 120 W * 1.25

= 150 W

Currnet = P/V

=150 / 12

= 12.5 A

Hence, fuse rating for 10 A load should be 12.5 A

4) Recommended voltage is 12V

Since, Power = V. I;

I = P/ V

Hence, I = 500/ 12 A

= 41.67 A

Battery capacity = current * time

= 41.67 * 1 AH

= 41.67 AH

Hence, the recommended capacity is 41.67 AH.

5)

• Generator and the Current and voltage regulator

They are cunnected in parallel because they have the same potential difference of the voltage across their ends.

6)

• Battery and the Starter

Because same current flow between the battery and the starter is desired.