Found 20 Articles for Electric Drives

What is Third Rail Traction System?A third rail is a method of providing electric power to an electric train through a semi-continuous rigid conductor placed along-side or between the running rails of a railway track.The third rail system uses an additional rail, called as conductor rail for supplying electrical power to the train. On most of the traction system, the conductor rail is placed on the sleeper ends outside the running rails, but in some cases a central conductor rail is used. The conductor rail is supported on ceramic insulators or insulated brackets, typically at intervals of 3 meters.The third ... Read More

A non-electric traction system is a type of traction system that does not use electrical energy for the movement of a vehicle at any stage.Types of Non-Electric Traction SystemThe most popular non-electric traction systems are −Steam Engine DriveInternal Combustion (IC) Engine Drive or Diesel Engine DriveIn this article, we will highlight the advantages and disadvantages of using these two types of non-electric traction system.Steam Engine DriveIn the steam engine drives, the reciprocating steam engine is used for getting the required motive power. The steam engine drive is not used in these days due to various reasons. However, it is still ... Read More

What is Electro-Extraction?Electro-extraction, also known as electro-winning can be defined in several ways as −Electro-extraction is an electrochemical process that is used for production of metals with commercially acceptable purity.Electro-extraction is the electro-deposition of metals from their ores that have been in electrolytic solution.Electro-extraction is the electrolytic process by which metals can be extracted or separated from their ores.Based upon the physical status of the metal ore, the metal can be extracted in following two ways −When the ore is in solid state - The ore is treated with strong acid to obtain its salt, again this salt is to ... Read More

DC Track Electrification SystemThe DC track electrification system is the one which uses 600 V DC to 750 V DC for urban railway services and 1500 V DC to 3000 V DC for main line services. In this DC system, the current collection system may be of the third rail type or overhead conductor type. In this system, the substation consists of a transformer and a mercury arc rectifier.25 kV AC SystemThis system of track electrification uses 25 kV industrial frequency AC supply collected from the overhead conductor and stepped down by a transformer in the locomotive. This reduced voltage ... Read More

In the direct current (DC) system, DC series motors are used for running the electric trains. The DC series motors are used in electric trains due to their following advantages −They have very high starting torque.DC series motor has smaller weight to power ratio.DC series motor has self-speed regulating property.They have low maintenance cost.The DC series motor has high acceleration and retardation.DC Electrification SystemIn the DC system of track electrification, the DC power to be fed to the DC series motor is obtained from substations which are located at a distance of 3 to 5 km for urban and suburban ... Read More

A negative booster is a separately excited DC generator whose armature is connected with negative bus-bar at the far end of the track through negative feeder. The connection diagram of the negative booster is shown in the figure below.As in case of DC traction system, the return current flows through the rails to the substations. Because of this current flow through the rails, some voltage drop exists along the track. Due to potential difference along the track, some of the return currents leak out to the earth and follow the path of low resistance provided by water pipes, gas pipes, ... Read More

Schedule Speed of an Electric TrainThe schedule speed of an electric train is defined as the ratio of the distance covered between two stops to the actual time of the run including the time for stop. The schedule speed is denoted by VS and is given by, $$\mathrm{\mathrm{Schedule\: speed}, \mathit{V_{\mathit{S}}}\:=\:\frac{\mathrm{Distance \:between\: two\: stops(\mathit{D})}}{Actual\: run\: time(\mathit{T_{\mathrm{run}}})\:+\:Time \:for\: stop(\mathit{T_{\mathrm{stop}}})}\:\:\:\cdot \cdot \cdot \mathrm{\left ( \mathrm{1} \right )}}$$$$\mathrm{\therefore \mathrm{Schedule\: speed}, \mathit{V_{\mathit{S}}}\:=\:\frac{\mathrm{Distance \:between\: two\: stops(\mathit{D})}}{Schedule\: time (\mathit{T_{S}})}\:\:\:\cdot \cdot \cdot \mathrm{\left ( \mathrm{2} \right )}}$$Where, TS is the schedule time in hours.Factors Affecting the Schedule SpeedThe factors that affect the schedule speed of an electric train ... Read More

The part of an electric motor that protects the motor from the contaminants in the environment in which it is operating and persons being from touch is called the motor enclosure.The motor enclosures are necessary for the following reasons −It protects the motor against foreign body and severe conditions.It protects the inner parts of the motor.It protects the operating personal from live parts of the motor such as winding terminals, slip rings, brushes, etc.Types of Motor EnclosuresIndian Standards (IS) 4691 have described codes for different types of enclosures. The most common types of electric motor enclosures are given as follows ... Read More

Electric motor drives are the basic assemblies used for the transformation of electrical power into mechanical energy. In simple words, the term "electric motor drive" is used to denote drives driven by electric motors.Types of Motors Used for Electric DrivesFollowing are the different types of motors used for industrial electric drives −DC series motorDC shunt motorCumulative compound DC motorSlip ring induction motorSquirrel cage induction motorDouble squirrel cage induction motorThree phase synchronous motorSingle-phase synchronous motorSingle-phase AC series motorRepulsion motorCapacitor-start induction-run motorCapacitor-start capacitor-run motorNow let's check in detail the applications of each of these motors.DC Shunt MotorDC shunt motor has medium starting ... Read More

Block Diagram of an AC LocomotiveThe following figure shows the block diagram of an AC locomotive.AC Locomotive - Function of Each PartThe working and function of each part of an AC locomotive is described below −The AC power at 25 kV is taken from the overhead conductor wire (called as catenary) through a pantograph and this high voltage supply is fed to a step–down transformer (provided with on load tap changer) installed in the locomotive itself, which converts the high voltage AC supply to low voltage AC supply.This low voltage AC supply obtained from the transformer is then converted into ... Read More