Electrical engineering deals with the study of how to generate, transmit and utilize the electrical energy. Electronics engineering, on the other hand, deals with the study of how to control and switch the flow of electrical energy in a circuit. Go through this article to find out the other major differences between electrical and electronics engineering.What is Electrical Engineering?Electrical engineering is the branch of engineering which deals with the generation, transmission, distribution and utilization of electrical energy.Electrical engineering is also concerned with study and design of electrical machines. The field of electrical engineering provides solutions for problems in various fields ... Read More

Mechanism of Train MovementThe essential mechanism of an electric locomotive is shown in the figure below.Here, the armature of the driving motor has a pinion of the diameter d1 attached to it. The tractive effort at the edge of the pinion is transferred to the driving wheel by means of a gearwheel.Let, T = Torque exterted by the motor in NmF1 = Tractive effort at the pinionFt = Tractive effort at the wheel$\gamma $ = Gear ratiod1 = Diameter of piniond2 = Diameter of gear wheelD = Diameter of driving wheel$\eta $ = Efficiency of power transmission from motor to ... Read More

There are two types of AC system of track electrification −Single-Phase Low-Frequency AC System (15 kV to 25 kV at 16$\frac{2}{3}$ Hz, 25 Hz and 50 Hz)Three-Phase AC System (3.3 kV to 3.6 kV at 16$\frac{2}{3}$ Hz)Single-Phase Low-Frequency AC SystemIn a single-phase low-frequency system of track electrification, an AC voltage of 15 kV at a frequency of 16$\frac{2}{3}$ to 25 Hz is used.The use of high voltage AC in the system reduces the current flowing through the overhead transmission line resulting in the reduced voltage drops and it helps in installing the substations at larger distances, about 50 to 80 ... Read More

The speed-time curve of a main line service is best and most easily replaced by trapezoid. The figure shows the simplified trapezoidal speed-time curve for the main line service.Let, $\mathit{V_{m}}$ = Crest speed in kmph$\alpha$ = Acceleration in kmphps$\beta$ = Retardation in kmphpsT = Total time of run in seconds$\mathit{t_{\mathrm{1}}}$ = Acceleration time in seconds$\mathit{t_{\mathrm{2}}}$ = Free running time in seconds$\mathit{t_{\mathrm{3}}}$ = Retardation time in secondsD = Total distance of run in kmTherefore, the time of acceleration in seconds is given by, $$\mathrm{\mathit{t_{\mathrm{1}}}\:=\:\frac{\mathit{V_{m}}}{\alpha }}$$And the time for retardation in seconds is, $$\mathrm{\mathit{t_{\mathrm{3}}}\:=\:\frac{\mathit{V_{m}}}{\beta }}$$Hence, the time for free running in seconds is, ... Read More

For urban and suburban services, the simplified quadrilateral speed-time curve of electric traction is shown in the figure.Let, $\alpha$ = Acceleration in kmphps$\beta$ = Braking retardation in kmphps$\beta_{c}$ = Coasting retardation in kmphpsV1 = Maximum speed at the end of acceleration in kmphV2 = Speed at the end of coasting in kmphT = Total time of run in secondst1 = Acceleration time in secondst2 = Coasting time in secondst3 = Braking time in secondsD = Total distance travell in kmTherefore, the time of acceleration is given by, $$\mathrm{\mathit{t_{\mathrm{1}}}\:=\:\frac{\mathit{V_{\mathrm{1}}}}{\alpha } }$$The time of coasting is given by, $$\mathrm{\mathit{t_{\mathrm{2}}}\:=\:\frac{\mathit{V_{\mathrm{1}}}-\mathit{V_{\mathrm{2}}}}{\beta_{c} } \:\:\:\cdot \cdot ... Read More

Crest Speed of Electric TrainThe maximum speed attained by an electric train during running is termed as its "crest speed". It is denoted by Vm.Average Speed of Electric TrainAverage speed is defined as the mean of the speeds attained by the electric train from start to stop. In other words, average speed is defined as the ratio of the distance covered by the train between two stops to the actual time of run. The average speed of train is denoted by Va and is given by, $$\mathrm{\mathrm{Average\: speed, }V_{a}\:=\:\frac{\mathrm{Distance\: between \:two\: stops\: (\mathit{D})}}{\mathrm{Actual\: time\: of\: run (\mathit{T_{\mathrm{run}}})}}\:\mathrm{kmph}}$$Schedule Speed of Electric ... Read More

Photometry and PhotometerThe measurement of light's brightness or luminous intensity is known as photometry. Photometry focuses on the perceived brightness to the human eyes. The photometry takes into account the eye's sensitivity to varying degrees of light and focuses primarily on the visible light spectrum.Thus, the photometry involves the measurement of candle power. The candle power of a given source of light in any given direction is measured by comparison with a standard source. In order to eliminate the errors in the measurement of the candle power, the measurement is performed in a dark room with dead black walls."The device ... Read More

A source of light that is mounted on a lamp column or pole either on the side of the road or within the median to provide illumination is known as street lighting.Street lighting is required along the road to have safer, comfortable, convenient and efficient movement of vehicles at night.Objective of Street LightingThe primary objectives of street lighting are −Street lighting is required to increase or enhance the community value of the street.Street lighting is provided along the road sides to make traffic and obstructions on the road clearly visible in order promote safety and convenience.Street lights also make the ... Read More

Spot WeldingThe welding process which is used for welding two or more metal sheets together by applying pressure and heat from an electric current to the weld area is known as spot welding.Spot welding is a type of resistance welding process, which is why it is also known as the resistance spot welding.Schematic DiagramThe figure below shows the schematic diagram of resistance spot welding −Spot welding is the simplest and most universally adopted method of making lap joints in thin sheet up to a maximum thickness of 12.7 mm.A typical spot welding machine consists of a transformer to produce high ... Read More

Seam WeldingThe welding process in which two similar or dissimilar materials are joined at the seam by the application of heat generated from electrical resistance is known as seam welding. The seam welding is a types of resistance welding, in which weld is produced by roller electrodes instead of tipped electrodes.Most seam welding processes produce a continuous or intermittent seam weld near the edge of two overlapped metals by using two machine driven roller electrodes. As in the seam welding process, the roller electrodes move over the metal workpieces, the workpieces are under pressure and the current passing through them ... Read More