Project - Analysis of a practical automotive wiring circuit

Project - Analysis of a practical automotive wiring circuit

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

• Battery
• Generator
• Current and Voltage regulator
• Starter
• Breaker
• Fuse
• Foot selection switch
• Gas tank unit
• Ignition coil

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

Battery: It is an essential component of the automotive system, as it serves as a source of electrical power. It stores energy in chemical form and convert it into electrical energy. The batteries are connected in series and parallel combination to get the required voltage and capacity. The starter motor of the engine is directly connected to the battery and it helps to start the engine. As the engine keeps running, the alternator (generator) charge the battery. When the engine is not running, the battery can supply the required power to the electrical components.

Generator (Alternator): A generator is one of the vital component of an automotive charging system and it plays a very crucial role. It converts mechanical energy into electrical energy. It supplies the required power to the battery as well as other electrical components of the automotive system. Since the alternator output is AC, it is converted to DC using rectifiers in order to charge the 12V battery. The energy required for the components of the vehicle system is supplied directly by the alternator, by the battery, or combination of both based on the conditions under which the alternator is functioning.

Voltage regulator: It controls the alternator’s power output. It contains a transistor, zener diode and other components. Voltage regulator keeps the output voltage of the alternator with in the safety limit to protect the electrical components in the vehicle. The current regulator or a current limiter prevents the alternator output from increasing beyond the rated output value of the alternator. If the voltage drops below 13.5V, the regulator’s sensors close the circuit, the alternator is switched on, increasing the power to the battery. If the battery voltage reaches 14.5V, the regulator disconnects the alternator and preventing it from charging the battery. This avoids the overcharging of the battery.

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

Given:

Load current = 10A

Normally the fuse rating is given by 125% of the rated current.

So, the required fuse rating for 10A load is = 1.25*10 =12.5A

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

Given,

Load power = 500W

Battery voltage =12V

Power = V*I

500 = 12*I

I= 500/12 = 41.66A

Capacity = current * time

The recommended capacity = 41.66*1hr = 41.66Ah

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

Generator and voltage regulator are connected parallel to each other. If two components are connected in parallel, the voltage across them are equal. In order to measure the voltage across the generator, the voltage regulator is connected parallel to the generator

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

The battery and the starter are connected in series. In the series connection, the current flows through them are equal. So, the starter is connected in series with the battery to get the required current.