Project - Analysis of a practical automotive wiring circuit
1 Answer :
Followings are the major element in given automotive wiring diagram :
1. Battery - An automotive battery is a type of rechargeable battery that supplies electric energy to an automobile vehicle.
2. Starter - A starter (also self-starter, cranking motor, or starter motor) is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power.
3. Ignition Coil - An ignition coil is an induction coil in an automobile's ignition system that transforms the battery's voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel.
4. Distributor - A distributor is an ignition component that, as its name implies, distributes spark to each of the engine’s spark plugs.
5. Generator - a unit that converts mechanical energy into electrical energy and provides a constant and continuous battery charge when the engine is running
6. Current and Voltage regulator - It controls the voltage and current produced by the car's alternator to recharge the battery.
7. Ignition Switch - It is a switch in the control system of an vehicle that activates the main electrical systems for the vehicle as well as responsible for starting the vehicle.
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2. Answer :
1. Battery :
The Battery is a collection of cells.
The chemical reactions occurs in the battery results in flow of electricity in a circuit.
The first battery was invented by Alessandro Volta in 1800.
It stores Energy and provide DC current.
Purpose of Battery :
The primary purpose of an automobile battery is to provide power for starting the vehicle. Initially battery provides high current for short period of time to start the starter motor.
It also acts as a surge protector for the car's computer.
And provides power for short-term use of electrical accessories like lights, stereo or wipers when the engine is off.
Battery also stores energy from car's generator(called as altenator which converts mechanical energy to electriacal energy) and provides current to other electrical components when needed.
Working of Battery :
Below are the major components of batteries used in automotive Vehicle
Container – Is a part made of the steel can, used to enclose the substances of the cell to form a cathode, which is a part of the electrochemical reaction.
Cathode – is a manganese dioxide and cathode.it is the electrode reduced by the electrochemical reaction.
Anode – anodes are electrodes that oxidized. They are made of powered zinc metal.
Electrolyte – is the medium for movement of ion within the cell. It carries the ionic current inside the battery.Different types of batteries rely on different types of chemical reactions and different electrolytes. Generally,an automobile lead-acid battery usually uses sulfuric acid to create the intended reaction.
Collector – is a brass pin in the middle of the cell that conducts electricity to the outside circuit.
A battery converts a chemical reaction into electrical energy.
Typically, automobile batteries have six cells, containing two plates at each.
One of the plates is made of lead and the other with lead dioxide.
Each cell can produce about 2-volts of energy.
The plates are submerged in Sulphur acid that allows the two plates to react.
This acid will trigger a reaction on the lead dioxide plate causing it to create ions and lead sulphate.
The ions created by the lead dioxide plate react to the other plate to produce lead sulphate and hydrogen.
This result in a chemical reaction that produces electrons, the electrons move around the plates and generate electricity.
The electricity flows out through the terminals to start the car and power other electrical components of the car.
2. Starter
Purpose of Starter Motor
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.
Being an electrical component, a starter consists of a powerful DC (Direct Current) electric motor and a solenoid.
The solenoid receives positive power direct from the battery and hearth current from the engine body. In order to turn the engine, a 12-volt battery must be used to run the starter. This means the battery has to be sufficient enough to power the device.
The starter motor has only one main function which is the first and second rotations the engine needed.
Working of Starter
Below are starter motors parts and their functions:
Armature :
An armature is an electromagnet component that is mounted on the driveshaft or bearings for a guide. It is made of a laminated soft iron core which is wrapped with numerous conductor loops or windings.
Commutator :
A commutator is a section of the shaft at the rear of the housing on which brushes run to conduct electricity. It is made of two plates mounted to the axle of the armature, the plates provide connections for the coil of the electromagnet.
Brushes:
Brushes are parts that run on a section of the commutator at the rear of the housing. it rubs the commutator and conducts electricity.
Solenoid :
The solenoid features two coils of wire that are wrapped around the core. This solenoid serves as a switch that connects and close the electrical connection between the starter motor and the vehicle’s battery.
Plunger :
The function of a plunger in a starter motor is to push forward so the pinion can be engaged.
Lever fork
The lever fork is connected to the plunger which makes them push forward together to engage the pinion.
Pinion
A pinion is a small mechanism containing gear and springs. It engages immediately the engine started, by extending the gear to the flywheel teeth. The flywheel is the source of engine rotation.
Field coils
The field coils are held in housing with screws as it consists of two or more coils connected in series. These coils receive power from the battery that converts them into an electromagnet that turns the armature. This creates a magnetic field around the armature.
When the ignition key is pressed, the battery voltage goes to through the starter control circuit to activates the solenoid.
The starter motor is powered by the solenoid, which helps to push the starter gear forward to mesh with the engine flywheel.
This flywheel is mounted on the engine crankshaft, so as the starter motor spins it turns the flywheel so as the crankshaft.
As soon as the engine start, the system disengages from the flywheel.
3 Generator
Purpose
In automobile vehicle generator also called as Alternator.
An alternator, as an integral part of every combustion engine vehicle, its main responsibility is to convert mechanical energy to electrical energy so that it can charge and replenish the battery in engine and other electrical components in a car.”
As the engine provides only mechanical energy, it does not generate electricity. So we need a power source which produces electricity to power all the electrical accessories in car. And that's where the alternator comes in.
The vehicle's charging system consists of a car battery, the voltage regulator, and the alternator. Your alternator converts mechanical energy to electrical energy with an alternating current.
The stator and rotor inside the alternator work as magnets and rotate to generate the alternating current. Then the alternating current(AC) is transformed into a direct current(DC) that charges the battery.
Both overcharging and undercharging the battery can be a serious issue. The voltage regulator sends the power from the alternator to the battery, controls the amount of energy to provide a steady flow of power to the battery.
Working of an Alternator
Alternator components & their functions:
Regulator :
The voltage regulator controls the amount of power distributed from the alternator to the battery in order to control the charging process. Regulators are designed with different functions and work depending on their specification.
Rectifier :
The rectifier is used to convert current from alternating current (AC) to direct current (DC) during the charging process.
Rotor :
The rotor is the spinning mass inside the alternator that rotates via the pulley and drive belt system. The rotor acts as a spinning electromagnet.
Slip rings :
The Slip rings are used as a means of providing direct current and power to the rotor.
Slip rings End Bearing:
The bearings are designed to support the rotation of the rotor shaft.
Stator :
The stator consists of several coils of wire wound through an iron ring. The stator sits outside the rotor, when a magnetic field is created the electrical current is made.
Drive End Bearing :
The bearings are designed to support the rotation of the rotor shaft.
Pulley :
The pulley is connected to the rotor shaft and the drive belt system. Rotation created by the engine the drive belt system turns the pulley beginning the charging process.
The working of AC car alternator is quite simple and less complex. It contains two windings such as a stator (stationary outside winding) and a rotor (rotating inner winding). The voltage regulator supplied voltage to the rotor winding which energizes and turns it into a magnet. Via a pulley, the rotor is rotated by the engine through a drive belt.
As the magnetic field is produced by the rotating rotor, it induces AC electric current in the stationary stator winding. The diodes help to convert the AC current into DC current the vehicle’s electrical system requires. Generally, voltage regulators are built-in in the alternator. They controlled the out voltage.
Automobile alternators are relatively small and lightweight, constructed with an aluminium outer housing. this light metal does not magnetize, which is why dissipates heat produce during the process and because the rotor assembly produces a magnetic field. There is a vent on both the front and back of the alternator, it also helps in the heat dissipation.
As the engine is running, the crankshaft turns the drive belt that spins the alternator pulley. And as the alternator rotates the current is produced. This is why it’s said that alternators transfer the engine’s mechanical energy of the engine into electrical power for the car components.
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3 Answer :
Although care is taken to properly design electrical and electronic circuits; overcurrents
in the form of short-circuits and overload can occur.
The sole purpose of fuse is to protect equipment from serious harm when an overcurrent condition arises.
An overcurrent is a condition which exists in an electrical circuit when the normal load current is exceeded. The two basic forms of an overcurrent are overloads and short circuits.
A short-circuit is an overcurrent condition where an abnormal, low-resistance, circuit
path is introduced into the circuit. This low-resistance path bypasses the normal
load and can create extremely high currents.
An overload is an overcurrent condition where the current exceeds the normal full
load-capacity of the circuit but where no fault condition (short-circuit) is present
In order to select the right amperage of the fuse, we first need to know the full-load steady-state current of the circuit at an ambient temperature of 25º C (68º F).
Once the current value is determined, then a fuse rating should be selected as to be 135% of this
value (taken to the next standard value).
As per given question, if the total load normal steady-state current is 10 amps from battery,
then a 15A fuse rating should be selected
[10 amps x 135% = 13.5 amps, the next larger standard size is 15A].
It is important to note that if the fuse is intended to be used in an environment with possibly very high or low ambient temperatures, then the nominal fuse current would need to be sized significantly higher or lower.
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4 Answer :
As per given condition,
Load (P) = 500 W
Assuming battery Voltage (V) = 12 V
Firstly we need to calculate how much current is required for given 500W Load in order find battery capacity.
Hence for calculating current,
Power = Volatage * Current
P = V* I
500W = 12V * I
I = 500W/12V
Therefore I = 41.6 Ampere
Now for capacity of battery.
Basically ,A battery's capacity is the amount of electric charge it can deliver at the rated voltage
And it is calculated generally as how much current it can give for an hour.
Hence for given condition load is 500 W and we require 41.6A current contantly for given load for 12V battery.
Let assuming maximum current approximately 45A and C-rating is 1, So calculating battery capacity for one hour.
Battery capacity = Current supplied * time
Battery capacity = 45 A * 1h
Therefore Battery capacity = 45Ah
So the recommended battery capacity should be 45Ah.
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5 Answer :
From given automobile wiring diagram, Horn and Sealed Beam Headlights are connected in parallel.
The reason they are connected in parallel because in a parallel circuit, every component is connected with the battery and there is the same voltage across each component.
As they shared common nodes the voltage accross all end is constant only current varries.
Hence the componets can work with theire rated power without any problem.
Also a parallel circuit is better than a series circuit because in case of any failure only the component connecting the faulty pathway will stop working.
All the other pathways of the circuit remain unaffected by the failure.
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6 Answer :
From given automobile wiring diagram, Fuse and Stop Light Switch are connected in parallel.
A series circuit provides exactly one path between any two points for electric current.
These circuits have the advantage of making each component very dependent on the other components.
This means that if one component is removed, all of the components turn off.
In this given circuit it is connected in series because in case of any overload current than rated current or short circuit in circuit, before that current going to the Stop light switch it will first flow through fuse.
That excessive current will blow the fuse and current stop flowing forword which protects the component because the current has to flow through every component in the circuit,the current stays consistent and at the same level throughout the circuit.
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