Project - Analysis of a practical automotive wiring circuit

Aim: Analysis of a practical automotive wiring circuit

Given Data:

Hint- take battery voltage =12V

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

Battery

Starter Motor

Connecting Wires

Ignition Coil

Distributor

Breaker

Generator

Current and voltage regulator

Ammeter

Junction Block

Horns

Lamps

Foot selector switch

Explain the purpose and working of any three elements briefly.

Battery:

To store the electrical energy and use it as per the requirement.

Generator:

With engine as prime mover its purpose is to generate electricity and power the electrical system and also to charge the battery when the vehicle is running.

Breaker:

Its purpose is to disconnect the electrical supply in case of any faults in the circuit which may lead to fire.

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

A fuse is a weak link in an electrical circuit. It may seem odd to design a purposeful weak link but, by choosing where this link is, appliances, people and businesses are kept safe.

When a circuit overloads, the following happens:

• The wire fuse element heats up quickly.
• The fuse then melts or explodes, depending on the current.
• The broken fuse interrupts the flow of electricity.

The conditions for this to happen are dependent on the fuse rating. The fuse rating relates to the strength of current allowed through the circuit, which changes depending on the type of appliance.

If an appliance has a motor, for example, it will have a rating of around 13 Amps, while a more dangerous appliance with a heating element, like a toaster, will have a smaller rating of 7 Amps.

The more potentially dangerous an appliance is, the lower the fuse rating will be.

To calculate the fuse rating

Power (watts) = Voltage x Current (amps)

Power = 12*10 = 120W.

Amps = Watts / Voltage

Amps = 120/12 = 10A

For factor of safety and to avoid short circuit current fuse rated current should be more than 25% of the max current .

So 25% of 10A = 12.5A.

So a fuse of rating nearby 12.5A should be used.

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

Given data;

I=10A (from the previous question)

P=500W

V=?

C=?

we know that,

From the power formula,

P=V*I

V=P/I

V=500/10 = 50V.

Voltage of the battery should be =50V

capacity (C)= I*T = =10*1 = 10Ah

So the capacity of the battery should be= 10Ah.

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

Lamps should be connected in parallel as there are many lamps and they are switched on as desired like while braking brake lamps should be on. 

Parallel connection is desired when the appliances need to work independently even when the other is not working. In series connection all the appliances connected in the circuit should work.

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

battery and starter Motor  are in series to each other because same current flows throw them.

Ammeter:An ammeter is a device which measures the amount of current flowing in a circuit. It is a very low resistance(nearly zero) device. If it is connected in parallel, it wiil draw most of the current due to the negligible resistance and will be damaged.