Found 53 Articles for Electric Traction

In this article, we will see how booster transformers are used in electric traction systems for reducing the interference with the communication systems. We will also take a look at the methods of connecting the booster transformer in a traction system.In AC traction systems, the return current mainly flows to the substation through the track. Some portion of this returning current flows through the earth because of leakage of current from the track to the earth. This leakage current causes a heavy interference with the neighbouring communication lines. Therefore, it is required to avoid this interference by some means like ... Read More

What is a Trolleybus?A trolleybus is an electric bus that draws its electricity from overhead wires, which are generally suspended from roadside posts, using spring loaded trolley poles. The trolleybus is also known as trolley coach or trackless trolley or trackless tram. The trolleybus is a pneumatic tyre vehicle.In case of trolleybus, two wires and poles are required to complete the electric circuit. It is fed usually at 600 VDC from the overhead contact wires by means of two collectors. In trolleybus drives, a DC compound motor of output of 50 to 100 kW is usually employed.The speed control in ... Read More

Specific Energy ConsumptionThe amount of energy input to the traction motors is known as energy consumption of the train. It is the energy consumed for the propelling the train. The total energy drawn from the distribution system is greater than this energy and is equal to the energy consumed by the various parts of the train and the quantity of the energy required for lighting, heating, control and braking, etc.This amount of energy consumed by the various parts of the train per ton per kilometer is termed as specific energy consumption and is expressed in watt-hours per ton per km. ... Read More

What is Pantograph Collector?The current in the overhead system is collected with the help of a sliding contact collector mounted on the roof of the vehicle. The pantograph current collector is used in the railways for collection of current from the overhead system where the operating speed of the train is as high as 100 kmph to 130 kmph and the current to be collected are as large as 2 kA to 3 kA.The pantograph is mounted on the roof of the vehicle and carry a sliding shoe for contact with the overhead trolley wire. It consists of a jointed ... Read More

When the train is accelerated up to a certain speed it requires energy, which is known as kinetic energy, corresponding to that speed. This kinetic energy is given by the expression, $$\mathrm{KE\mathrm{\: =\: }\frac{1}{2}\mathit{mv^{\mathrm{2}}}}$$During coasting period, a part of this stored energy is utilized in propelling the train against frictional and other resistances to motion of the train and hence the speed of the train decreases. Therefore, coasting may be considered as a form of mechanical regenerative braking.The saving in the energy consumption can be considerably affected by increasing the coasting but it will decrease the schedule speed of the ... Read More

What is Regenerative Braking?The method of braking in which no energy is drawn from the supply system during braking period and some of the energy (kinetic energy of rotating parts) is fed back to the supply system is known as regenerative braking.The regenerative braking is the most efficient method of electric braking to the driving motor of locomotives. The regenerative braking can be applied to both AC and DC motors.Advantages of Regenerative BrakingThe advantages of the regenerative braking include the following −In case of regenerative braking, a part of electrical energy is returned to the supply system, so the total ... Read More

In this article, we will throw some light on the different safety and protective devices used in electric elevators.Electric elevators are the electrically operated devices which are used for lifting up and down, moving load in suitable direction, and lifts in multistoried buildings for facilitating up and down movements of occupants. Therefore, it can be said that an electric elevator is an electrically operated device used for transporting at a fixed place.Safety and Protective Devices Used in ElevatorsThe elevator safety device is the part of elevator which is used for protecting the elevator so it can run safely. The primary ... Read More

In this article, we will take a look at the different types of electric motors used in the elevators. We will also discuss the suitability of different motors in different types of elevators, power calculation, starting torque requirements, and speed control methods of elevator motors.What is an Elevator Motor?An elevator motor is an electric motor which is used for up and down movements of elevator car. The turning force produced by the elevator motor is transmitted to the rope winding drum to wind or unwind the rope, so that the elevator car moves up and down.The elevator motors are specially ... Read More

The transition methods are defined as the methods of changing over the connections from one grouping to another. Depending upon the change over from full series to first parallel, the transition methods employed in the electric traction system are of the following three types −Open Circuit TransitionShunt TransitionBridge TransitionLet's discuss each of these transition methods in detail.Open Circuit TransitionThe steps involved in the open-circuit transition are shown in Figure-1. In case of the open-circuit transition, first the series connection between the motors is disconnected and power is switched off with full load current.Then, some of the starting resistance is reinserted ... Read More

This article is about AC generator and DC generator, and the main differences between the AC and DC generators.What is a Generator?An electrical machine which converts the mechanical energy input into electrical energy output is called the generator or electric generator.Though, the electrical energy generated by the machine can be of either AC (Alternating Current) or DC (Direct Current). Hence, based on the type of supply produced by the generator, they are of two types viz. −AC Generator (or Alternating Current Generator)DC Generator (or Direct Current Generator)Both of these alternators apply same principle (Faraday’s law of electromagnetic induction) to generate ... Read More