Electrical World

Synchronous Motor             A Synchronous motor is electrically identical with an alternator or A.C. generator .It can define as an A.C. Motor in which at steady state rotation of the shaft is in Syn with the frequency of the applied current.In Synchronous motor the total number of rotations made by the shaft is equal to the applied current.In Synchronous motors unlike induction motor multiphase A.C electromagnets are present on the stator which produces a rotating magnetic field.Here rotor is of a permanent magnet which gets synced with the rotating magnetic field and rotates in synchronous to the frequency of current applied to it.Most synchronous motors are rated between 150KW and 15MW and run at speed ranging from 150 to 1800 rpm. Types of Synchronous Motor            According to the method of magnetization of the rotor we have two types of synchronous motors. Non-excited. Direct current excited.   ...

Induction Motor        Induction motor (asynchronous motor) is an AC motor in which the electrical current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.So their is no need of electrical connection to the rotor. Working Principle         In an induction motor the rotor does not receive power by conduction but by inductions is exactly the same way as the secondary of a two winding transformer receive its power from the primary.that is why such motor are known as induction motors.In other words we can say that an induction motor is a rotating transformer in which primary winding is stationary but the secondary is free to rotate.            If we consider supply voltage we have two types of induction motors. Single phase induction motor and three phase induction motor.Single phase induction motor is not self starting where as three p...

Sub-Station             The Electrical Sub-Station is the part of a power system in which the voltage is transformed from low to high or high to low for transmission,distribution,transformation and switching.The main components of an electrical Sub-Station are power transformer,circuit breaker,bus-bar,lighting arrester and insulator. Lighting Arrester            It is used for the protection of the equipment at the sub-station against travelling waves.It is connected between the line and earth in parallel with the equipment to be protected at the sub-station. Single Line Diagram of sub-Station Working of Sub-Station                  Electricity has to be transmitted over large distances as the place where the power is being generated and the place where it is consumed can be far apart.The electricity is transmitted at very high voltages and low currents to reduce...

Full-Wave Bridge Rectifier                      A Full-Wave Bridge Rectifier is a circuit arrangement which makes use of both half cycles of input alternating current (AC) and converts them to direct current (DC) .In full-wave bridge rectifier we used four diode in the form of a bridge as shown in the diagram below.  Comparison of FW-Bridge rectifier With Center Tapped Transformer                      The FW-bridge rectifier uses four diodes instead of two but the it eliminated the need of a center-tapped transformer.The PIV-rating of the diode used in FW- Bridge rectifier should be better than Vmax rather than 2Vmax if we compared it with FW-rectifier with a center-tapped transformer.This means that the diodes used in FW-bridge rectifiers are cheap as diodes of high PIV-rating are always more expensive used in FW-Rectifier with center tapped transformer ,this is b...

Electromagnetic Induction Magnetism and Electricity                Whenever an electrical current flows through a conductor a magnetic field is establish in the space which surrounds the conductor.In other words we can say that when electrons are in motion they produce a magnetic field.                  when we place a moving conductor inside the magnetic field ,electrons are starts flowing inside the conductor.The phenomena of current produced E.M.F. .When a conductor cut magnetic field or a conductor placed in a changing magnetic field is known as electromagnetic Induction. Production of Induced E.M.F. and Current Condition 1               In this condition our coil is fix and we will move the magnet.The arrangement is shown in the  fig.(a ). When both coil and magnet are stationary we will observe no deflection in the galvanometer.When we bring the...

Full-Wave Rectifiers                There are two types of full-wave rectifier circuits.one is uses two diodes with a center tapped transformer and the transformer have equal turns Ns1 and Ns2 of the secondary windings which is shown in the fig. below The second type of FW-rectifier is having bridge-rectifier circuit and uses four diodes and it does not require a center-tapped transformer it only have simple transformer. fig. Comparison of HW Rectifiers and FW  Rectifiers                  The FW-rectifier circuits are better if we compare with HW rectifier circuits in all most all respects.FW-rectifiers have double the value of dc voltage delivered to load their efficiency is also double and their ripple factor is low.Due to these reasons FW-rectifiers are preferred over HW-rectifiers. Simple FW-Rectifier with Center-Tapped Transformer fig        ...

Diode                Diode is a semiconductor device having two terminals typically allowing the flow of current in one direction only.One important application of diode is in rectifier circuits.Rectifiers converts cheaply available mains(ac) power supply voltage in a dc power supply.Electronic circuits such as television,receivers,radio and many more need a dc power supply. Rectifiers                 We have main three types of rectifier circuits. Half wave rectifier circuits. Full wave bridge rectifier circuit. Full wave rectifier with center tapped transformer. Half Wave rectified        fig.                          A basic half wave rectifier circuit is show in the diagram in which                                ...