Project - Analysis of a practical automotive wiring circuit

1.The major elements in the above automotive wiring are:

• Battery
• Generator
• Starter
• Distributor
• Breaker
• Fuse
• Ammeter

2.Battery:

A battery is a device that stores chemical energy and coverts it to electrical energy. It is a source of elctric power consisting of one or more electrochemical cells with external connections for powering electrical devices.

working:

A battery works on the oxidation and reduction reaction of an electrolyte with metals. When two dissimilar metallic substances, called electrode, are placed in a diluted electrolyte, oxidation and reduction reaction take place in the electrodes respectively depending upon the electron affinity of the metal of the electrodes. As a result of the oxidation reaction, one electrode gets negatively charged called cathode and due to the reduction reaction, another electrode gets positively charged called anode.difference in electron concentration causes an electrical potential difference developed between the metals. This electrical potential difference or emf can be utilized as a source of voltage in any electronics or electrical circuit.

a.Breaker:A circuit breaker is an electrical switch designed to protect an electrical circuit from damage caused by overcurrent/overload or short circuit

working:

The circuit breaker is opened by applying pressure to the trigger. When there is a faulty current flowing through any part of the system, the trip coil of the breaker gets energized thereby moving away from each other, thus opening the circuit.

b.Ammeter:

An ammeter is a measuring instrument which is used for the measurement of electric current in an electric circuit.

working:

An ammeter has a low resistance. The ammeter is connected in series with the load to measure the electric current flowing through it. As, the ammeter has a very low resistance, therefore when it is connected in series with any circuit, it does not change the current.

When the ammeter is connected in series with the load, the same current flows through the ammeter that flows through the load, this is because the current in a series circuit remains same through all the circuit elements. Therefore, the deflection in the ammeter coil is according to the amount of load current. In such a way, the ammeter measures the load current in an electric circuit.

3. The fuse rating should be always 125% of the load current.

Therefore, for the load of 10A the fuse rating should be 12.5A.

6. Ammeter and ignition switch are connected in series.They are connected in series because the current flowing through them is same, but the voltage between them is different.

5.Two horns are connected parallel to each other, these two horns are situated near the junction block. They are connected in parallel because the voltage is same between them and current flowing will be different.

4. Power P = 500W

P = V*I

500 =12*I

I = 500/12

I = 41.66A

Therefore, Battery capacity = A*T

Assuming time = 1 hr

Battery capacity = 41.66*1

= 41.66Ah

if we take time as 3 hours

Battery capacity = 41.66*3

=124.98Ah

if we take battery capacity of 125Ah it will take 3 hours to discharge when 500W load is connected, so i would recommend 125Ah battery.