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 ... 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 ... 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 ... 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 ... Read More

What is Tractive Effort?The effective force required for propelling a train at the wheel of locomotive is known as the tractive effort. It is denoted by 𝑭𝒕 and is measured in Newton. It is a vector quantity always acting tangential to the wheels of the locomotive.Tractive Effort for Propulsion of ... Read More

What is a Speed-Time Curve?Speed-time curves are the most convenient means of studying the movement of trains and their energy consumption. A speed-time curve is defined as the graph plotted between the speed and time, by taking speed (in km/hour) on the Y-axis and time (in seconds or minutes) on ... Read More

Power Output from the Driving AxlesLet, 𝐹𝑡 = Tractive effort in Newton𝑉 = Speed of the train in kmphSince, the power output is defined as the work done per unit time, i.e., $$\mathrm{Power\: output, \mathit{P}\mathrm{\: =\: }Rate\: of \: work\: done\mathrm{\: =\: }\frac{Work \: done}{time}}$$$$\mathrm{\Rightarrow \mathit{P}\mathrm{\: =\: }\frac{Tractive\: effort\times Distance}{Time}\mathrm{\: ... Read More

In the plain rheostatic starting method, the voltage across the traction motor is gradually increased from zero to full line voltage and the current is kept constant at normal rated value by reducing the external resistance gradually.Let, 𝑇 = Starting period in seconds𝑉 = Line voltage in volts𝐼 = Constant ... Read More

In this article, we will take a look at the various methods used for starting and controlling the speed of DC series motors.Rheostatic ControlThe basic traction motor circuit with rheostatic starting is shown in the figure below.A DC series motor can be started by connecting an external resistance in series ... Read More

In electric traction, the control equipment is required for −Connecting the motors to the supply mains without taking excessive current at start and provide smooth acceleration without causing sudden shock so as to avoid damage to the coupling.Adjusting the speed as per requirement.Providing rheostatic or regenerative braking.The master controller system ... Read More