Project - Analysis of a practical automotive wiring circuit

1. Identify each of the major elements in the above automotive wiring diagram.

A) Battery

B) Starter

C) Fuse

D) Ignition switch and ingnition coil set up

E) Gas tank unit and gauge set up

F) Instrument lights set up

G) Generator

H) Distributor

I) Junction box/block

J) Ammeter

K) Breaker and set up

L) Horn and horn set up

M) Current and voltage regulator

N) Foot selector switch

2. Explain the purpose and working of any three elements briefly.

BATTERY:

Definition: The battery is an electro-chemical device. It uses chemical to produce electricity. The amount of
electricity it can produce is limited. As the chemical in the battery is depleted, the battery runs
down and is discharged. It can be recharged by supplying it with electric current from the vehicle
alternator or from a battery charger. The depleted chemicals are restored to their original
condition as the battery becomes charged.

Purpose: The automotive battery supplies electric current to operate the starting motor and ignition system
while starting the engine. It also acts as a voltage stabilizer by supplying current for the lights,
radio and other electrical accessories when the alternator is not handling the load. In addition, the
battery supplies a small amount of current to the volatile memory in the electronic control
module while the ignition key is off. The specific gravity test and the open voltage test are
conducted to find out the state of charge in the battery. Load test is performed to find out the
battery condition.

STARTER:

Definition: A starter or starter motor is an electrical device that used to rotate (crank) internal combustion engines so as to initiate the engine’s operation under its own power. As soon as the engine begins to run, it got disconnected from the engine, which now relies on the combustion process. The component is mounted on the engine’s gearbox housing, and the starter motor gear meets flywheel’s teeth.

Purpose: The engine cannot start the combution process on its own, and while at zero rpm. It has to be turned over by an external force. The external force is provided by starter.

It converts the electric energy from the battery into mechanical energy.

It provides the mechanism to engage with the flywheel crank the engine.

FUSE:

Definition: An electrical fuse is a safety device that operates to provide protection against the overflow of current in an electrical circuit. An important component of an electrical fuse is a metal wire or strip that melts when excess current flows through it. It helps to protect the device by stopping or interrupting the current.

Purpose: Prevents device failure due to faulty circuit operation.

Fuse prevents short-circuits.

Prevents overload and blackouts.

Prevents damage that is caused due to mismatched loads.

3. If the total load is 10A from battery, what should be the fuse rating?

Fuse Rating = Wattage / Voltage

Wattage = Current * Volatge

Fuse Rating = Current * Volatge / Volatge

Given, I = 10A & V = 12 V

Fuse rating = 10 * 12 / 12

Fuse rating = 10 A (Minimum fuse should be used).

4. If 500W is the load, what is the voltage and capacity of battery you recommend?

Assume 500W load is need for the system for 1 hour,

Energy need E = Power x time

= 500 W x 1 h

E = 500Wh

Given,

Voltage = 12 V

Battery Capacity Q (Ah) = E (Wh) / V (V)

= 500/12

Battery Capacity Q (Ah) = 41.66 Ah

Battery capacity needed is 41.6 Ah

60Ah battery is standard battery available.

So, the recommended battery voltae and capacity is 12V 60Ah battery.

5. Identify any two elements which are connected parallel to each other. Why they are connected in parallel?

Horn button with horns: Horn button with horns is connected in parallel,because it is operate in same voltages

but in different currents.

Light switch with the lights: Light switch is connected with parallel to all the lights,because each light

requires different power.

6. Identify any two elements which are connected in series. Why they are connected in series?

Battery and Ammeter: The battery is connected to the Ammeter in series to measure the current from the battery, In series connection current is same.

Battery and Starter: Battery and starter are connected in series because the starter needs the direct and high current from the battery.