Electric Locomotives with 3-phase Drives

Introduction   Till electronics came into the field of traction recently, the best suited drive for traction application was the dc series motor because of its inherent characteristics to give high torque at low speeds and vice-versa. The dc series motor was the best solution found for meeting the actual service as well as control requirements. On a fixed frequency, the asynchronous motor has a characteristic which is not well suited for traction application. However, this motor is of rugged construction when compared to a dc motor and requires much lower inputs… Read More

Railway Production in India

Production of Rolling Stock Indian Railways have set up production units for Rolling stock and Rolling Stock components Apart from production for use of Indian Railways, these production units export Rolling Stock and components to many countries such as Burma, Bangladesh, Sri Lanka, Hungary, East Africa, Central Asian countries, East Asian countries etc. The following are the production units of Mechanical Department for production of different types of Rolling Stock: List of Production Units Name of PU Place where situated Chittaranjan Locomotive Works Chittaranjan Diesel Locomotive Works Varanasi Integral Coach Factory Chennai… Read More

Fuse, Types and Characteristics

Fuses A fuse is a device that protects a circuit from an over current condition only. It has a fusible link directly heated and destroyed by the current passing through it. A fuse contains a current-carrying element so that the heat generated by the flow of normal current through it doesnot cause it to melt the element; however, when an over current or short-circuit current flowsthrough the fuse, the fusible link will melt and open the circuit. The Underwriter Laboratories (UL) classifies fuses by letters e.g. class CC, T, K, G, J,… Read More

Types of Relays

An electrical relay is a switch that is used for controlling circuits. Today you’ll learn about different types of electrical relays. Electromagnetic attraction type The magnetic force produced by undesired current attracts the armature of the relay. Electromagnetic attraction type relays can operate on either a.c or d.c quantities. They are further divided into three types: Attracted armature type Solenoid type Balance beam type Induction type relay The working of Induction type relays relies on the electromagnetic induction phenomenon. They are only used for a.c quantities. They are further classified into two… Read More

General Application of Induction Motors

The induction motor is the most popular machine that is widely employed in process and manufacturing industries. Alongside manufacturing facilities, it is the most popular machine for domestic purposes. Deep Well Water Pumps Deepwater wells use a special type of induction motor with a compact diameter and longer length. Refrigerator and Compressors Refrigerators and other compressuse split type induction motors in their working principle. Small water pumps Small water pumps use single phase induction motors. Ceiling fan Ceiling fans use single phase induction motors in their working. The video below displays repairing of a… Read More

Hydroelectric Plants in India

  Hydroelectric power is a major electrical power generation source. Advantages: Clean Fuel The only fuel required for hydroelectric power generation is water. It is clean resource, has no pollutants, burning, or any sort of chemical reactions associated with it. Small running charges Compared to coal, gas, diesel power station and power stations, the hydroelectric station has very small running charges. Renewable Power generation through hydroelectric stations relies on the water cycle. Water comes through the reservoir, flows through penstock, passes through turbines, exits the station and joins some river. In fact,… Read More

Types and Classification of Faults on Electrical Power Systems

Question: How many types of faults exist on the power system and how they are classified? Answer: Generally four types of faults exist and are classified into two categories. Symmetrical faults: They give rise to symmetrical equal currents having a displacement of 120°. Unsymmetrical faults: They gave rise to unsymmetrical currents having unequal displacements. List contains: Line to line to line fault Line to ground Line to line Double line to ground Types of Fault Classification Severity of Fault 3 Line Symmetrical Most Dangerous Line to Line Unsymmetrical Fault More Dangerous Line… Read More

Power in DC and AC Circuits

Formulas of Power in DC, AC Single Phase and AC Three Phase Circuits   Back to basic, below are the simple Power formulas for Single Phase AC Circuit, Three Phase AC Circuits and DC Circuits. You can easily find electric power in watts by using the following power formulas in electric circuits. Power Formulas in DC Circuits P = V x I P = I2 x R P = V2 / R Where: P = Power in Watts V = Voltage in Volts I = Current in Amperes R = Resistance in Ohms (Ω) Power Formulas in Single Phase AC Circuits P = V x I x Cos Ф P = I2 x R x… Read More

Basic Electrical Engineering Laws and Theorems

Ohm’s Law Statement: The current flowing through any resistor is directly proportional to the voltage applied to it. Mathematically, V = IR Kirchhoff’s Current law We all know that current is a basic feature of circuits which exists due to flow of charges. Kirchhoff’s current law explains the behavior of current at any junction. Statement: The current flowing towards any junction (node) is equal to the current flowing away from that node. Mathematically, ∑ Current In = ∑ Current out. In other words, this law is also called the law of conservation of charge. Kirchhoff’s… Read More

Transformer Rating in kVA, and not in kW or kVAR. Why?

Question: Why transformer rating is expressed in kVA instead of kW or kVAR? Answer: At the time of manufacturing, the nature of load to be connected is not known. (i.e it is resistive, reactive, R, RL, RC, RLC or of any other type). Therefore it is beneficial to express power in terms of voltage and amps. This V & A represents the overall power delivered to any sort of load. The power supplied to a resistive load is the product of voltage times current flowing through it. In case of ac loads,… Read More