Tag: Mechanical

Introduction

An engine used to convert mechanical energy into electrical energy is an AC generator. Steam turbines, gas turbines, water turbines, and other similar devices all generate this energy. It creates a sinusoidal waveform of alternating current. Alternators are another name for AC generators. The electromagnetic induction law of Faraday is the foundation of an AC generator. According to this rule, anytime a conductor is exposed to a variety of magnetic fields, an electromotive force (EMF) is generated across it. This EMF is referred to as an induced EMF. Electromagnetic induction is the term for this phenomenon. Induced electromagnetic induction is the process by which a coil develops a potential difference as a result of changes in the magnetic flux flowing through it. Several types of AC generators, including polyphase generators, rotating field generators and spinning armature generators.

For more details watch the video of the Science Course for classes 6th, 7th, and 8th.

What is an AC Generator?

An AC generator is an engine that converts mechanical energy into electrical energy in the form of an alternating driving force. To provide a consistent magnetic field, an AC generator uses two magnet poles.

AC Generator Parts and Function

An electromagnet with two poles, the North Pole and the South Pole, is a component of an AC generator.  Below is a discussion of certain AC generator components, including the rotor, slip rings, and armature loop.

a. Field

The output voltage of an AC generator is obtained from the source using conductor loops. The field’s main function is to provide a magnetic field that will stimulate the gadget.

b. Armature

The armature coil is a coil that is part of the generator and produces output voltage. An armature coil’s job is to move electricity through the generator.

c. Prime Mover 

The primary mover of an AC generator is either an engine or a turbine. It serves as the appliance’s power supply.

d. Rotor 

A rotor is a revolving component with magnetic field spirals. It generates the necessary output voltage.

e. Stator

A stationary part holding the armature spirals is called a stator. A stator includes three different parts. They are stator frame, stator core, and armature spirals.

1. Stator frame: A frame that grips the stator core and armature spirals.
2. Stator core: There are slots in the inner part of the core that hold the armature spirals. A steel or iron is coated on the walls of the stator core to decrease the eddy current losses.
3. Armature winding: They are bounded on the stator core.

f. Slip Rings

There are two small rectangular blocks fixed with slip rings called carbon brushes. They are attached to the galvanometer.

Principle of Electric Generator

The basis of AC generators is Faraday’s law of electromagnetic induction. A current-carrying coil placed in a consistent field of force produces the driving force that is referred to as the law.

Construction and Working of an AC Generator 

An AC generator consists of a rectangular coil with two magnet poles attached to it on either side. Two rings are used to fasten the coil’s (or loop’s) perimeter. The rings are joined together with brushes. When a conductor travels in a magnetic field, an electric 

The generator induces a current in it.

Between the magnet’s poles, a rotating rectangular coil, also known as an armature, is used. The magnetic field’s vertical axis is the centre of rotation. The flux in contact with the armature changes as it rotates constantly. The alteration in flux results in the generation of an emf. As a result, the galvanometer, slip rings, and carbon brushes produce an electric current. While direct current only travels in one direction, alternating current sometimes flips direction.

The production of the AC generator shown in the above graph is described as

1. Induced EMF is zero when the coil is at point A because it moves equidistantly from the magnetic field’s curve at that point.
2. A gradient of 90o is created between the coil‘s motion and the magnetic field as it moves from point A to point B, and induced EMF is at its highest level during this time.
3. Moving the coil from A to B results in the same motion being equally far from the magnetic field and no generated EMF.
4. The induced EMF is once more at its highest when the coil is moved from C to D since its motion is antiparallel to the magnetic field and its angle is 270o.
5. The coil completes one cycle and moves equally far from the magnetic field when it moves from D to A. Induced EMF is therefore zero.

Advantages of AC Generator Over DC Generator

Category	AC Generator	DC Generator
Output Voltage	Higher Output Voltage.	It cannot generate a higher output voltage as it damages the functioning of the commutator.
Construction	Simpler construction	Construction is complicated due to a commutator.
Functioning	Works on the principle of electromagnetic induction.	DC generator functioning is more complex than an AC generator.
Maintenance	It demands less maintenance.	It demands more maintenance than an AC generator.
Cost	Cheaper	Costs higher than AC generator
Efficiency	Transmission efficiency is higher as AC reduces transmission losses.	Transmission efficiency is lower.

You can also read “What is AC Voltage Capacitor?” for explanation of AC voltage.

Summary

A generator is an engine that changes one type of energy into another. Large currents are produced by electric generators for usage in industrial and domestic applications. There are two different kinds of electric generators: DC generators, which convert mechanical energy into direct current. A generator of alternating current that converts mechanical energy. On the Faraday law of EMI theory, an AC generator was placed. In an AC generator, the flux in contact with the armature varies as it rotates continuously. The shift in flux causes an emf to be generated. As a result, the galvanometer, slip rings, and carbon brushes produce an electric current. As an AC generator produces higher output voltage, it is easier to build, requires less maintenance, is more efficient, and is less expensive than a DC generator. Large currents are produced by electric generators for usage in industrial and domestic applications.

Frequently Asked Questions 

1. Can we Generate EMF without Rotating the Coil in an AC Generator? Explain.

Ans: Yes, emf may be produced without the coil revolving. If the armature is made to move at a velocity perpendicular to the magnetic field, Emf can also be produced.

2. What is the reason for Heat Loss in the Generator?

Ans: Reasons for the heat loss in the generator can be, (a) generation of the by-products like carbon dioxide, and molecular friction, which can reduce the efficiency. The heat loss hinders the efficiency of the generator. So, the efficiency is never 100%. 

3. What is the Driving Force?

Ans: Induced emf is also termed as the driving force and can be expressed as, 

                                                      ε = N B Aωsinωt

where N is the number of turns in the coil, B is a magnetic field, A is an area, ω is the angular velocity

So, in an AC generator, the induced emf is proportional to the applied magnetic field.

4. Give examples of DC Sources.

Ans: The electrical appliances like radios, televisions, and solar panels. DC only travels in one direction and lacks any polarity.

Introduction

The ability to work emanates with energy. For any action, we require energy in the form of mechanical, chemical, electrical, static, kinetic, muscular, and other forms. Understanding the several energy sources is necessary for utilising all forms of energy, which can be obtained from various sources, including both natural and artificial ones. Interestingly, natural energy sources include the sun, wind, tidal, geothermal, and gravitational energies, while artificial energy sources include biomass, coal, petroleum, and a host of others. To ensure that the energy resources survive for a long time, it is crucial to save and use them as effectively as possible. Although not all energy sources release dangerous gases, their use can occasionally lead to pollution. Moreover, energy comes in two forms: traditional and unconventional sources.

Conventional Sources of Energy

Conventional energy sources are non-renewable, which implies that after they have been utilised, they cannot be reused. Coal, oil, natural gas, fuel wood, and nuclear energy are a few examples of traditional/conventional sources of energy. Coal, natural gas, and petroleum account for 90% of the commercial energy produced worldwide, while nuclear power accounts only for 10%.

Types of Conventional Sources of Energy

a. Coal

• Coal, a sedimentary rock in the black-brown range, is the most prevalent conventional energy source and has a long lifespan of 200 years. Long-term exposure to heat and pressure transforms dead plants into lignite and anthracite, which are then finally transformed into coal.
• There are several applications for coal, such as fuel for steam engines in trains and the production of electricity.
• About 70% of the total energy used in our nation is generated by coal.

b. Oil

• Due to the variety of uses for oil, it is one of the most significant conventional energy sources.
• The oil extraction procedure, which entails several processes, is used to obtain the oil.
• Oil is utilised commercially and in a variety of sectors, including the food, cosmetic, and transportation industries.

c. Petroleum and Natural Gas

• Petroleum is made up of Alkanes and cycloalkanes.
• Methane, ethane, propane, butane, and hydrogen sulphide are all components of natural gas.
• Natural gas is created when gas comes into contact with the petroleum layer and is a black liquid when it is in its raw state.
• Petroleum is used to make things like plastic, petrol, and diesel.
• Compared to other fuels, natural gas produces less air pollution.

d. Nuclear Energy

• Nuclear materials that contain radioactive elements are used to create energy.
• 300 or more nuclear reactions are required for the production of nuclear energy.
• Some negative effects of nuclear energy include its radioactivity and danger.
• From one location to another, it is simple to travel by rail or ship. For instance, coal, oil, and natural gas are raw materials.

Advantages of Conventional Sources of Energy

• For any energy, the installation of conventional plants is simple.
• There is no need to wait for energy to be generated because it may be produced quickly depending on the needs.
• Alternative forms of energy are readily accessible and renewable resources that may be utilised again.
• Solar energy, wind energy, tidal energy, geothermal energy, biomass, and solar energy are a few examples of non-conventional sources.

Non-conventional Sources of Energy 

• Alternative forms of energy are readily accessible and renewable resources that may be utilised again.
• Solar energy, wind energy, tidal energy, geothermal energy, biomass, and solar energy are a few examples of non-conventional sources.

Solar Energy

• In solar power plants, sunlight is transformed into electrical energy to produce solar energy.
• Although solar energy is the most significant non-conventional energy source, it is also the least consumed.
• Solar energy comes from renewable resources, is widely accessible, and is non-polluting. 
• Solar ovens, solar panels, solar heaters, and solar cells are a few examples.

Wind Energy

• Turbines are used to generate electricity from wind as a source of energy.
• The power output rises along with the wind speed.
• These wind turbines are situated where the wind speed is strongest and at its highest altitude.
• Wind energy is positioned close to agricultural regions and is pollution-free.

Biomass Energy

• Wood, sewage, plants, animals, and other organic materials are used to create biomass.
• Burning this material releases heat energy, which is then transformed into electrical energy.
• Cooking, lighting, and the production of power are among the uses of biomass.
• A total of 14% of the world’s energy comes from biomass.

Tidal Energy

• Tidal energy is produced by turning the mechanical energy of tides into electricity.
• This energy source can be used in areas that are close to oceans and seas.

Advantages of Non-Conventional Sources of Energy

• These resources are very less expensive and renewable.
• Non-conventional sources are environmentally friendly.
• These resources require low maintenance.
• Offer long-term use as compared to conventional sources.

A comparison between the Conventional and Non-Conventional Sources of Energy.

Conventional Source of Energy	Non-Conventional Source of Energy
Conventional sources of Energy is being used for a longer period.	Non-conventional energy sources have lately been created and are environmentally beneficial.
Conventional resources are a prominent cause of environmental pollution due to the emission of gases and smoke.	Since non-conventional energy is derived from renewable
Non-renewable sources of energy.	Renewable sources of energy.
Examples – Coal, Petroleum, Natural Gas, oil, and Nuclear Energy.	Examples-Wind Energy, Solar Energy, Tidal Energy, Hydropower Energy, and Thermal Energy.

Summary

Conventional sources of energy emit greenhouse gases while producing power and are limited, therefore then-conventional energy sources, which are renewable and environmentally favourable are suitable for sustainability. The major conventional energy sources are coal, oil, petroleum, natural gases, etc. while the non-conventional sources include solar energy, wind energy, tidal energy, biomass energy, etc.

Frequently Asked Questions

1. Why should we Conserve Energy?

Ans: Energy conservation is a measure used to protect and preserve energy sources from becoming extinct. We must save our energy supplies for later use. Utilisation must be reduced to conserve. Our needs are growing daily, yet we only have a limited amount of energy resources. 

2. What is a Renewable Source of Energy?

Ans. Renewable energy comes from naturally occurring, regenerative sources. Renewable energy sources include wind, solar, biomass, thermal, etc. Renewable energy can be continuously replenished without running out.

About 16% of the world’s energy consumption is made up of renewable sources. Renewable energy is a plentiful and sustainable source of power. Sunlight is the most significant and widely available renewable energy source.

3. What are the Advantages of Non-Conventional Sources of Energy over Conventional Sources of Energy?

Ans. The natural limitations of conventional energy sources, which emerged after millions of years and are subject to extinction at any time, make them very vulnerable. The abundance of non-traditional energy sources in nature makes them increasingly significant and practical. Additionally, non-traditional sources of energy are environmentally beneficial and don’t damage or contaminate the environment. The cost of fuel generated from unconventional energy sources is lower than that of traditional energy sources.