## Electric Power Distribution System Basics

Updated on 02-Jul-2021 09:23:45
What is a Distribution System?The part of the power system that distributes electric power for local use is called as distribution system. Generally, a distribution system is the electrical system between the substation fed by transmission system and the consumer’s meters. A typical distribution system is shown in the figure.Components of Distribution SystemDistribution Sub-Station – A distribution sub-station is the electrical system which transfers power from transmission system to the distribution system of an area.Feeders – A feeder is a conductor which connects the distribution sub-station to the area where power is to be distributed. The current in a feeder remains ... Read More

## Electric Machine Losses and Efficiency with Examples

Updated on 02-Jul-2021 09:18:53
There are two types of electric machines viz. static electric machines (e.g. transformer) and rotating electric machines (e.g. motors and generators). All electric machines are not ideal, therefore they have some losses due to which efficiency being less than 100%. In general, we come across three popular electric machines viz. transformer, DC machines (motor & generator) and AC machines (motor & generator), therefore we will discuss the loss and efficiency in these machines one by one.Losses in a DC machinesThe losses in DC machines may be divided into three categories as −Copper LossesCopper losses occur due to currents in windings of ... Read More

## Electric Generator: Construction and Working Principle

Updated on 02-Jul-2021 09:13:16
The electric generator is an electromechanical energy conversion device, which converts mechanical energy into electrical energy.Construction of Electric GeneratorAn electric generator has following main parts −Magnetic Field SystemArmature CoreArmature WindingYokeMagnetic Field SystemThe magnetic field system is used to produce uniform magnetic field in the electric generator within which the armature rotates. The field system may be composed of either permanent magnets (small generators) or electromagnets (in large generators). Generally, the field system of a practical electric generator consists of poles on which the field coils are mounted. When field coils are energised, a magnetic field produces within the generator.Armature CoreThe ... Read More

## Capacitors in DC Circuits

Updated on 02-Jul-2021 09:10:58
Capacitor & CapacitanceWhen any two conducting surfaces are separated by an insulating material, it called as a capacitor. The conducting surfaces are known as plates of the capacitor and the insulating material is known as dielectric.The ability of a capacitor to store charge is termed as capacitance of the capacitor. It is denoted by C and measured in Farad (F).By experiments, it has been found that charge (Q) stored in a capacitor is directly proportional to the potential difference across it, i.e., $$Q\varpropto\:V$$$$\Rightarrow\:Q=CV$$$$\Rightarrow\:C=\frac{Q}{V}\:\:\:\:...(1)$$Where, C is a constant, known as capacitance of the capacitor.Hence, the capacitance (C) of a capacitor is ... Read More

## Capacitor Types: Fixed & Variable Capacitors

Updated on 02-Jul-2021 08:57:11
Capacitors can be classified depending upon their fixed or variable capacitance as follows −Fixed CapacitorsThose capacitors whose value of capacitance is fixed during the manufacturing and cannot be changed later are known as fixed capacitors. The symbol of the fixed capacitor is shown in figure.The fixed capacitors are classified into two categories as −Polarized CapacitorsNon-Polarized CapacitorsPolarized CapacitorsThose capacitors which are having the specified positive and negative polarities, are called as polarized capacitors. When these capacitors are used in the circuits, they should be connected in perfect polarities.Polarized capacitors are further classified as −Electrolytic CapacitorsThose capacitors in which some electrolyte is ... Read More

## Basics of Three-Phase Electricity

Updated on 02-Jul-2021 08:45:42
The phase-electricity is produced by a 3-phase generator that has three separate but identical windings, which are called phases. The 3-phase windings of the 3-phase generator are displaced 120° apart from each other and rotate in a common uniform magnetic field. Therefore, a three-phase generator produces three voltages of the same magnitude and frequency but 120° electrical apart from one another.Consider a three-phase alternator as shown in the figure. It has three identical windings or coils R, Y and B displaced 120° electrical from each other and rotating in anticlockwise direction with an angular velocity ω in a magnetic field ... Read More

## Ammeter: Definition & Working Principle

Updated on 02-Jul-2021 08:41:35
An ammeter is a measuring instrument which is used for the measurement of electric current in an electric circuit.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.Working PrincipleWhen 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 ... Read More

## Alternative Ways of Generating Electricity

Updated on 02-Jul-2021 08:33:34
Apart from the conventional methods of generating electricity (like thermal, hydroelectric, gas turbine, nuclear power etc.), there are also some alternative methods of generating electricity, which are as follows −Solar PowerThe electricity can be generated from the heat of the sun. In the solar power system, the energy of sunlight is converted into electricity, either directly by the photovoltaic cell or indirectly by using concentrated solar power or combination of both.In solar power generation, the sunlight strikes onto the PV cells, which converts the energy of sunlight into direct current, that can either be stored into batteries or converted into ... Read More

Electrical power is generated, transmitted and distributed in the form of 3-phase power because it has the following advantages over the single phase system −The three phase power has a constant magnitude while the power in single phase system is the function of supply frequency i.e. pulsates from zero to maximum value at twice the supply frequency. It can be seen from the following equations, 1 − phase power, $$p=\frac{V_{m}I_{m}}{2}-\frac{V_{m}I_{m}}{2}\cos2\omega\:t$$3 − phase power, $$p=\sqrt{3}(V_{L}I_{L}\cos\varphi)$$In the 3-phase system, a rotating magnetic field can be created in stationary windings, whereas this cannot be done in a single phase system.For the same rating, ... Read More
Absolute Magnetic PermeabilityThe absolute (or actual) magnetic permeability of a material is its conductivity for the magnetic flux. It is denoted by a Greek letter μ ‘(mu)’ and measured in Henry per meters (H/m). Thus, Absolute permeability of material, $$\mu=\mu_{0}\mu_{r}\:H/m$$Where, μ0 = absolute permeability of air or vacuum.μr = relative permeability of the material.The higher the permeability of a magnetic material, the greater its conductivity for magnetic flux and vice-versa.Air or vacuum is the poorest conductor of the magnetic flux. The absolute magnetic permeability of the air is μ0 = 4π × 10−7 H/m . The absolute permeability (μ) of a ... Read More