Volt-Ampere and Watts are power measurement units. Volt-ampere is used to measure the total power that is being consumed by a device. Watts is used to power the device so it can perform its useful work. The product of voltage and current in an AC (alternating current) circuit is known as a unit of apparent power, or VA. It shows the overall power used by a device, which includes both the useful power used and the power lost as a result of inefficiencies like reactive power. The real power used by a gadget to carry out productive work is measured ... Read More

Chain drive and belt drive are the common methods for transmitting power between two spinning shafts in various mechanical systems. Both of these drives are commonly used in applications including autos, industrial machinery, and agricultural equipment to transfer power from one place to another. Belt drive uses pulleys and a flexible belt to transmit power, whereas chain drive uses a metal chain and sprockets to transmit power between two spinning shafts. Read this article to find out more about Chain Drive and Belt Drive and how they are different from each other. What is a Chain Drive? The chain ... Read More

The method in which no energy is drawn from the supply system during braking period and some energy is fed back to the supply system is known as regenerative braking.Calculation of Energy Returned During RegenerationWhen the train is accelerated up to a certain speed, then it acquires energy, (known as kinetic energy), corresponding to that speed and this kinetic energy is given by, $$\mathrm{KE\mathrm{\: =\: }\frac{1}{2}\mathit{mv^{\mathrm{2}}}}$$During coasting period, a part of this stored energy is utilized in propelling the train against frictional and other resistances to motion and hence the speed of the train falls. Under ideal conditions, i.e. no ... Read More

Energy output is the energy required for the propulsion of a train, it is mainly for accelerating the train from the rest to maximum velocity (Vm) and the energy required to overcome the gradient and track resistance to motion.The specific energy output is defined as −$$\mathrm{Specific\: Energy\: Output\mathrm{\: =\: }\frac{Energy\: output\: in \: watt \: hours}{Weight\: of\: train\: in\: tons\times distance\: of\: run\: in \: km}}$$The specific energy output is measured in watt-hours per ton-km. The specific energy output is used for comparing the dynamic performances of trains operating to different schedules.Determination of Specific Energy Output of an Electric TrainAssume ... Read More

In this article, we will see what a synchronous motor is and how it differs from an asynchronous motor. We will compare and contrast the various features of synchronous and asynchronous motors.What is an Electric Motor?The electrical machines that convert electrical energy into mechanical energy are known as electric motors. Based on the electric supply input to the motor, they are of two types viz.: AC motor and DC motor. The AC motors are further classified into two types viz. − synchronous motors and asynchronous motors. These motors have some similarities and some differences in their construction, operation and performance.What ... Read More

Both Metro trains and conventional trains are popular modes of transportation used by the public for moving from one place to another. In this brief article, we will see how these two types of trains differ in their features.Metro TrainMetro trains are high-speed trains that are powered by the electricity grid. In general, a metro train has four to five air-conditioned coaches. Actually, the metro trains are the new era transportation concept developed by many countries to control the pollution created by conventional vehicles and traffic caused by them. The metro train is one of the fastest ways to travel ... Read More

In this article, we will compare and contrast the features of a capacitor and highlight how it differs from an inductor, considering various parameters such as stored energy, flow of current, behaviour in AC and DC circuits, types and applications, etc.What is a Capacitor?An electric circuit element which has ability to store the charge in electrostatic field is known as capacitor. The capacitor is a passive circuit element because it cannot generate and amplify the power in a circuit. Generally, a capacitor consists of two metallic plates, placed parallel to each other and are separated by a dielectric medium. The ... Read More

In this article, we will have a detailed discussion regarding electric drives, their types, and how AC Drives and DC Drives differ in their features.What is an Electric Drive?An electrical or electronic device which is used for controlling the speed of an electric motor is known as an electric drive. The electric drives are constant and variable speed controllers and extensively used in industrial automation and robotics. The basic block diagram of an electric drive is shown in the figure below.Based on the nature of electric current, the electric drives are of following two types −AC Drives (Alternating Current Drives)DC ... Read More

In this article, we will take a detailed look at the various features of AC and DC motors and highlight their differences. An electric machine that converts electrical energy (either AC or DC) into mechanical energy is known as an electric motor. Based on the type of input electric supply, electric motors are classified into two types, viz. −AC MotorDC MotorWhat is an AC Motor?An AC motor is one that converts AC electrical power at input into mechanical power at output by using the principle of electromagnetic induction. The AC motor takes alternating current as the input. It consists of ... Read More

In this article, we will take a look at insulated overlap and uninsulated overlap, which are overhead equipment used in electric traction systems.What is an Overhead Equipment?Overhead Equipment (OHE) in electric traction system are used for transmitting electrical energy to the electric locomotives, trolley buses, trams and other electric traction systems.As in any electrical circuit, the series and parallel connections are made by twisting cables together, using junction box, soldering, brazing, etc. But, in case of overhead conductor wire (or catenary wire), the use of these equipment is not possible. Therefore, the arrangement employed for the same purpose in the ... Read More