Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 7: 302. Sky appears blue due to (a) radiation. (b) reflection. (c) refraction. (d) scattering of light over dus… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part VI: 252. The atomic hydrogen welding is based on the principle(s) of (a) obtaining atomic hydrogen by means of… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 6: 252. The atomic hydrogen welding is based on the principle(s) of (a) obtaining atomic hydrogen by means of a… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part V: 202. In resistance welding, the magnitude of current is controlled (a) by varying the primary voltage of the… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 5: 202. In resistance welding, the magnitude of current is controlled (a) by varying the primary voltage of the… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part IV: 152. For arc heating, the electrodes used are made of (a) copper. (b) graphite. (c) tungsten. (d) aluminium… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 4: 152. For arc heating, the electrodes used are made of (a) copper. (b) graphite. (c) tungsten. (d) aluminium… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 3: 102. The most suitable motor for a steel mill requiring a motor having high starting torque, wide speed rang… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part III: 102. The most suitable motor for a steel mill requiring a motor having high starting torque, wide speed ra… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part II:  52. The pair used for frequency converters is (a) squirrel cage induction motor and synchronous motor… Read More

Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part I: 1. The basic elements of an electric drive are : (a) electric motor and the transmission system. (b) electri… Read More

Power Supply for Electric Traction Interview Questions and Answers: 1. What is the arrangement of power supply on Kanpur-Tundla section ? Ans. 132 kV supply is taken at one point from the su… Read More

Braking and Mechanical Considerations Interview Questions and Answers: 1. Why ordinary mechanical braking cannot be totally replaced by electrical braking ? Ans. Because electric braking can… Read More

Control of Traction Motors Interview Questions and Answers: 1. The resistors employed for control of traction motors are designed for short-time rating. Why ? Ans. Because control resistors… Read More

Electric Traction Motors Interview Questions and Answers: 1. Why the magnetic circuit of a traction motor is not made of cast iron ? Ans. Because cast iron cannot withstand continuous vibrat… Read More

Train Movement and Energy Consumption Interview Questions and Answers: 1. What is meant by speed-time curve ? Ans. The curve drawn between speed and time taking speed on the Y-axis and time… Read More

Traction Systems Interview Questions and Answers: 1. Why steam engine drive is not suitable for urban and suburban services where distance between stations is small ? Ans. Because of low coe… Read More

Refrigeration and Air Conditioning Interview Questions and Answers: 1. What is practical unit of refrigeration ? Define it. Ans. Tonne of refrigeration (TR) is the practical unit of refrig&s&hell…Read More

Electrolytic Processes Interview Questions and Answers: 1. What is electrolysis ? Ans. The breaking of a substance (known as electrolyte) into ions by flow of electric current through it is… Read More

Illumination Engineering Interview Questions and Answers: 1. What are the advantages of artificial lighting produced electrically ? Ans. Artificial lighting produced electrically have the ad… Read More

Electric Welding Interview Questions and Answers: 1. What is welding ? Ans. Welding is a materials-joining process that produces coalescence of materials by heating them to the welding tempe… Read More

Power Flow Studies Interview Questions and Answers: 1. What is the purpose served by power flow analysis ? Ans. Power flow analysis provides a systematic mathematical approach for determinat… Read More

Power System Stability Interview Questions and Answers: 1. Define stability limit. Ans. A stability limit is the maximum power flow possible through some particular point in the system or th… Read More

Substations Interview Questions and Answers: 1. State any four types of substations according to the service ? Ans. The substations, according to the service rendered are: Transformer substa… Read More

Voltage Control Interview Questions and Answers: 1. Why is it necessary to keep the receiving-end voltage constant within specified limits ? Ans. For satisfactory operation of equipment/mach… Read More

Power System Earthing Interview Questions and Answers: 1. What is difference between system earthing and equipment earthing ? Ans. System earthing deals with earthing of the system neutral t… Read More

Travelling Waves Interview Questions and Answers: 1. What are the values of natural impedances for overhead lines and cables ? Ans. The value of natural impedance for an overhead line is bet… Read More

Protection against Over voltages due to Lightning Interview Questions and Answers: 1. What is meant by voltage surge ? Ans. By voltage surge is meant any sudden excessive rise in voltage tha… Read More

Protection of Feeders and Transmission Lines Interview Questions and Answers: 1. What is unit type protection ? Ans. Unit system of protection is one in which the protection responds to faul… Read More

Bus Bar Protection Interview Questions and Answers: 1. Why use of single bus-bar arrangement is restricted to small and medium sized substations and small power stations ? Ans. The glaring d… Read More

Transformer Protection Interview Questions and Answers: 1. What are the faults that are likely to occur in a power transformer ? Ans. The faults likely to occur in a power transformer are op… Read More

Protection of AC Generators and Motors Interview Questions and Answers: 1. What are the common types of generator faults ? Ans. The common types of faults occurring in synchronous generators… Read More

Static Relays Interview Questions and Answers: 1. What is static relay ? Ans. A static relay refers to a relay in which there is no armature or other moving element and response is developed… Read More

Protective Relays Interview Questions and Answers: 1. What is a protective relay ? Ans. Protective relay is an electrical device designed to initiate isolation of a part of an electrical ins… Read More

Circuit Breakers Interview Questions and Answers: 1. What do you understand by switchgear ? Ans. The apparatus employed for switching, controlling and protecting the electrical circuits and… Read More

Circuit Breaking Interview Questions and Answers: 1. What is a circuit breaker ? Ans. Circuit breaker is a mechanical device designed to close or open contact members, thus closing or openin… Read More

Fuses Interview Questions and Answers: 1. What is meant by a fuse ? Ans. Fuse is a device used in an electrical circuit for protecting electrical equipment’s against overloads and/or s… Read More

Unsymmetrical Fault Analysis Interview Questions and Answers: 1. Draw the sequence network for single line-to-ground fault without fault impedance. Ans. 2. Draw the sequence network connecti… Read More

Symmetrical Fault Analysis Interview Questions and Answers: 1. What is meant by fault level ? Ans. When fault occurs at a point in a power system, the corresponding MVA is referred to as the… Read More

Symmetrical Components Interview Questions and Answers: 1. What do you mean by Fortescue theorem. Ans. According to Fortescue theorem, any unbalanced three-phase system of currents, voltages… Read More

Representation of Power System Components Interview Questions and Answers: 1. What is meant by percentage reactance ? Ans. Percentage reactance can be defined as the voltage drop across the… Read More

Switchgear and Protection Interview Questions and Answers: 1. What is meant by short circuit ? Ans. When conductors of different phases come into contact with each other in a power line, pow… Read More

High Voltage DC Transmission Interview Questions and Answers: 1. Why is voltage regulation better in case of dc transmission ? Ans. Because of absence of inductance in dc systems. 2. Why the… Read More

High Voltage AC Transmission Interview Questions and Answers: 1. What are the transmission voltages that are used in India ? Ans. 33, 66, 110, 132, 220 and 400 kV. 765/800 kV is also in used… Read More

Interference of Power Lines Interview Questions and Answers: 1. How do power lines cause interference with neighbouring communication lines ? Ans. The transmission lines transmit bulk power… Read More

Insulation Resistance of a System Interview Questions and Answers: 1. What are the faults that are likely to occur in cables ? Ans. The faults which are likely to occur in cables are open ci… Read More

AC Distribution Interview Questions and Answers: 1. What is primary distribution system and what is normal operation voltage of primary distribution ? Ans. Primary distribution system is tha… Read More

Diesel Electric Power Plants Interview Questions and Answers: 1. What is the basic difference between a diesel engine and steam turbine ? Ans. The basic difference between a diesel engine an… Read More

Nuclear Power Plants Interview Questions and Answers: 1. Why are nuclear power stations becoming popular ? Ans. The need of nuclear power plant lies in the fact that the hunger for electrici… Read More

Steam Power Plants Interview Questions and Answers: 1. Why overall efficiency of a thermal power plant is very low ? Ans. In a steam power station, more than 50% of total heat of combustion… Read More

Hydroelectric Power Plants Interview Questions and Answers: 1. What is power generating station ? Ans. Power generation station generates electrical energy by conversion of energy available… Read More

Electrical Energy Interview Questions and Answers: 1. What is the per capita consumption of electricity in India ? Ans. 631 kWh in 2006. 2. Why electrical energy is more useful than other fo… Read More

Basic Electronics Interview Questions and Answers: 1. What is difference between active and passive devices? Ans. In passive devices, the time average power delivered to the device over… Read More

Network Analysis Interview Questions and Answers: 1. What is an electric network? Ans. An electric network is an interconnection of physical electrical devices such as an energy source… Read More

Electron Emission Interview Questions and Answers: 1. What is Fermi level? Ans. The maximum energy that an electron in a metal has at the absolute zero temperature is called the Fermi l… Read More

Electron Tubes Interview Questions and Answers: 1. What is an electron tube? Ans. An electron tube is an electronic device in which conduction of electrons takes place in an evacuated o… Read More

Semiconductor Physics Interview Questions and Answers: 1. Why copper is a good conductor? Ans. In case of copper the electrons in the conduction band are very large. An electron in the… Read More

PN Junction Diode Interview Questions and Answers: 1. What is a P-N junction? Ans. The contact surface between the layers of P-type and N-type semiconductor pieces placed together so as… Read More

Zener Diode Interview Questions and Answers: 1. What is a zener diode? Ans. Zener diode, also sometimes known as breakdown diode, is like an ordinary P-N junction diode except that it i… Read More

Rectifiers Interview Questions and Answers: 1. What is a dc power supply? Ans. The part of the equipment that converts ac into dc is called the dc power supply. 2. What is meant by rect… Read More

Bipolar Junction Transistors (BJTs) Interview Questions and Answers: 1. Explain why BJT is a polar device. Ans. Since both of the charge carriers (electrons and well as holes) are invol… Read More

Transistor Biasing and Stabilization Interview Questions and Answers: 1. Explain the term biasing. Ans. The proper flow of zero signal collector current and the maintenance of proper co… Read More

Logic Circuits Interview Questions and Answers: 1. What is a combinational circuit? Ans. In a combinational circuit, the output depends upon present input(s) only i.e., not dependent on… Read More

Digital Logic Families Interview Questions and Answers: 1. What is the difference between a bipolar logic family and unipolar logic family? Ans. Logic family using BJTs is known as bipo… Read More

Digital to Analog and Analog to Digital Converters Interview Questions and Answers: 1. Why conversion of an analog signal into an equivalent digital signal is essential? Ans. Because mo… Read More

Microprocessors Interview Questions and Answers: 1. What is a Microprocessor? Ans. Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and… Read More

Electronic Instruments (Analog as well as Digital) Interview Questions and Answers: 1. Why ordinary voltmeter cannot be used in electronic circuits? Ans. A moving coil voltmeter draws a… Read More

Cathode Ray Oscilloscope Interview Questions and Answers: 1. What is cathode ray oscilloscope (CRO)? Ans. A CRO is an electronic device with a CRT as its main component and other associ… Read More

Transducers Interview Questions and Answers: 1. Explain in brief the term transducer. Ans. Basically transducer is defined as a device which converts energy or information from one form… Read More

Basic DC Circuit Analysis Interview Questions and Answers: 1. Define Electric current. Ans. Electric current is defined as the rate of flow of electric charge. Where q is the charge is… Read More

Current Controlled Current Source (CCCS) Circuit: An ideal form of a Current Controlled Current Source (CCCS) Circuit by an input current is shown in Fig. 36.39. Such a circuit provides an o… Read More

Current Controlled Voltage Source (CCVS) Circuit: An ideal form of Current Controlled Voltage Source (CCVS) Circuit providing an output voltage controlled by an input current is shown in Fig… Read More

Voltage Controlled Current Source (VCCS) Circuit: An ideal form of a current source, whose output current Iout is controlled by an input voltage is shown in Fig. 36.35. Here, the output curr… Read More

Voltage Controlled Voltage Source (VCVS) Circuit: An ideal form of a voltage source, whose output voltage Vout is controlled by an input voltage Vin, is given in Fig. 36.33. The output volta… Read More

Current to Voltage Converter Circuit: A device that produces a voltage proportional to input signal current is called a Current to Voltage Converter Circuit. The circuit arrangement is shown… Read More

Voltage to Current Converter Circuit: Occasionally in industrial electronics, it is necessary to provide a current proportional to certain voltage, even though the load impedance may vary. A… Read More

Summing, Scaling and Averaging Amplifier: The most useful of the op-amp circuits employed in analog computers is the summing amplifier circuit. This circuit can be used to add ac or dc signa… Read More

Frequency Response of Common Mode Gain of Differential Amplifier: Low values of common-mode gain are desirable so that the circuit can reject undesirable signals that are applied equally to… Read More

Compensating Network in Op Amp: In op-amps the variations in gain and phase shift with respect to frequency are due to the internal capacitors and stray capacitances, which are due to physic… Read More

Frequency and Phase Response Curves of a Single Stage Amplifier: The voltage gain of a single-stage transistor amplifier commences to fall off at some high frequency. This fall-off may be du… Read More

Nuclear Waste Disposal and Safety: Introduction – Nuclear Waste Disposal and Safety from nuclear power plants activities, defense related nuclear weapon activities or other applic… Read More

Automatic Combustion Control System: Automatic Combustion Control System is very popular nowadays and this has been developed mainly to maintain load against demand, to prevent smoke, to inc… Read More

Economics in Plant Selection: Economics in Plant Selection – The plant capacity and size depends upon the power demand. A power plant should be reliable i.e. its capacity must be more… Read More

MHD Power Plant Working Principle: MHD Power Plant or Magneto Hydro Dynamic is concerned with the flow of a conducting fluid in the presence of magnetic and electric field. The fluid may be… Read More

Fuel Cell Working Principle and Schematic Diagram: Fuel Cell Working Principle explains that it is an electrochemical device that converts chemical energy of a conventional fuel directly int… Read More

Biogas Power Plant Working, Site Selection and Application: Introduction – Biogas is a combustible gas mixture of methane, carbon dioxide, water and hydrogen sulphide produced during t… Read More

OTEC Power Plant: Introduction – OTEC Power Plant or Ocean Thermal Energy Conversion is an energy technology, which uses the ocean’s natural temperature gradient to drive a turbi… Read More

Geothermal Power Plant Working Principle: Geothermal Power Plant Working Principle – The growing demand of power will exhaust all fossil fuel sources in few decades. Therefore there is… Read More

Types of Solar Power Plant: The surface of earth receives energy of 1014 kW from the sun. It is evident that sun will last for 1011 year. Even though the sun light is filtered by atmosphere… Read More

Pumped Storage Power Plant – Operating Modes and Types: Introduction – Pumped Storage Power Plant are generally used for peak loads. An interconnected system of pumped stora… Read More

Tidal Power Plant – Types and Working Principle: Introduction to tidal power plant – Gravitational force between the moon, the sun and the earth causes the rhythmic rising and lo… Read More

Wind Energy and Wind Power Plant: Wind is a form of solar energy. It is caused by the uneven heating of the atmosphere by the sun due to the irregularities of the earth’s surface, and… Read More

Turgo Turbine Working Principle: The Turgo turbine is an impulse water turbine designed for medium head applications. Operational Turgo Turbines achieve efficiencies of about 87%. It works w… Read More

Micro Hydel Power Plant – Components and its Workings: Micro Hydel Power Plant was the most common way of electricity generating in the early 20th century. The first commercial use of… Read More

Selection of Hydraulic Turbines: It is very important to select the type of Hydraulic turbine which will give maximum possible efficiency. The Selection of Hydraulic Turbines always match sp… Read More

Oil Pressure Governor and its Working Principle: The primary purpose of a governor for a hydro electric unit is to control the speed and loading of the unit. It is accomplished by controllin… Read More

Difference between Impulse Turbine and Reaction Turbine: The Difference between Impulse Turbine and Reaction Turbine is given below: SL no Impulse Turbine Reaction Turbine 1 The total availa… Read More

Kaplan Turbine Working Principle: Kaplan Turbine Working Principle – The water from the scroll casing flows over the guide vanes. It is deflected through an angle of 90° in between… Read More

Classification of Hydraulic Turbines: The important classification of hydraulic turbines are: 1. According to the type of energy Impulse turbine, and Reaction turbine If the energy available… Read More

Site Selection for Hydroelectric Power Plant: The Site Selection for Hydroelectric Power Plant includes several structures like dam, conduits intakes, surge tank, power house and many others… Read More