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Saturday, 26 November 2016

Protection of Power System - Multiple Choice Question

Protection of Power System - Multiple Choice Question Points : protection of power system multiple choice questions and answers, electrical objective type question answers, mcqs, protection of power system blanks 1. Overheating of a transformer may be due to
(i) overloads
(ii) short-circuits
(iii) failure of cooling system
(iv) all above

2. In an alternator, relay protection is absolutely necessary against
(i) over current
(ii) field failure
(iii) stator winding faults
(iv) none of above

3. When failure of prime-mover takes place3 the alternator
(i) runs as a synchronous motor
(ii) draws some current from the supply
(iii) is in the inverted running mode
(iv) all above

Friday, 11 November 2016

Switchgear - Multiple Choice Questions

Switchgear - Multiple Choice Questions Points : switchgear blanks, switchgear multiple choice questions and answers, electrical objective type question answers, mcqs 1. A circuit breaker performs the function of
(i) detection only
(ii) circuit interruption only
(iii) both detection and circuit interruption
(iv) none of above

2. An arc is produced when the switch of a high-voltage and large-current circuit is
(i) opened
(ii) closed
(iii) opened or closed
(iv) none of above

3. A fuse performs
(i) detection function only
(ii) circuit interruption function only
(iii) both detection and interruption functions
(iv) none of above

Saturday, 29 October 2016

Faults in Power System - Multiple Choice Questions

Faults in Power System - Multiple Choice Questions Points : faults in power system, multiple choice questions and answers, electrical objective type question answers, mcqs 1. The ratings of circuit breakers are generally decided on the basis of
(i) unsymmetrical fault currents
(ii) symmetrical fault currents
(iii) normal circuit currents
(iv) none of above

2. The most common fault on an overhead transmission line is
(i) single line to ground fault
(ii) three phase short-circuited fault
(iii) double line to ground fault
(iv) line to line fault

3. Reactors are used at various locations in the power system to
(i) increase short-circuit current
(ii) avoid short-circuit current
(iii) limit short-circuit current
(iv) none of above

Saturday, 8 October 2016

Distribution of Electric Power - Multiple Choice Questions

Distribution of Electric Power - Multiple Choice Questions Points : distribution of electric power, multiple choice questions and answers, electrical objective type question answers, mcqs 1. In the interconnected system, the reserve capacity of the system
(i) remains same
(ii) decreases
(iii) increases
(iv) none of above

2. As compared to overhead system, the underground system
(i) is more costly
(ii) has less chances of faults
(iii) has more useful life
(iv) all above

3. In primary distribution lines, the earth wire is placed
(i) above the phase conductors
(ii) below the phase conductors
(iii) inbetween the phase conductors
(iv) none of above

Tuesday, 20 September 2016

Electricity Overhead Lines - Multiple Choice Questions

Electricity Overhead Lines - Multiple Choice Questions Points : Electricity Overhead Lines, Electrical Overhead Lines multiple choice questions and answers, electrical objective type question answers, mcqs 1. The potential across the various discs of suspension string is different due to
(i) self-capacitance
(ii) shunt capacitance
(iii) both (i) and (ii)
(iv) none of above

2. In a string of suspension insulators, if shunt capacitance decreases, then string efficiency
(i) decreases
(ii) increases
(iii) remains the same
(iv) none of above

3. The wind pressure is directly proportional to
(i) speed of wind
(ii) square of speed of wind
(iii) square root of speed of wind
(iv) none of above

Friday, 2 September 2016

Electrical Supply System - Multiple Choice Questions

Electrical Supply System - Multiple Choice Questions Points : Electrical supply system multiple choice questions and answers, electrical objective type question answers, mcqs 1. If voltage is increased by n times, the size of the conductor would
(i) increase by n times
(ii) reduce by 1/n times
(iii) increase by n2 times
(iv) reduce by 1/n2

2. As a matter of economy, voltage for power transmission should be
(i) low
(ii) medium
(iii) high
(iv) none of above

3. In a supply system, the cost of conductor is
(i) directly proportional to area of cross-section
(ii) inversely proportional to area of cross-section
(iii) directly proportional to square of area of cross-section
(iv) none of above

Friday, 26 August 2016

Economics of Power Generation - Multiple Choice Questions

Economics of Power Generation - Multiple Choice Questions Points : Economics of Power Generation, multiple choice questions and answers, electrical objective type question answers, mcqs 1. In the diminishing value method for calculating depreciation, the annual depreciation charge is independent of
(i) useful life of equipment
(ii) scrap value
(iii) the rate of interest
(iv) initial value of equipment

2. A consumer who consumes more electrical energy should pay
(i) more fixed charges per unit
(ii) less fixed charges per unit
(iii) less running charges per unit
(iv) none of above

Thursday, 4 August 2016

Generation of Electrical Energy - Multiple Choice Questions

Generation of Electrical Energy - Multiple Choice Questions Points : Generation of Electrical Energy multiple choice questions and answers, electrical objective type question answers, mcqs 1. An alternator converts
(i) sound energy into electrical energy
(ii) mechanical energy into electrical energy
(iii) electrical energy into mechanical energy
(iv) none of above

2. The most clean power plant is
(i) steam power plant
(ii) diesel power plant
(iii) hydro-electric plant
(iv) nuclear power plant

3. Diesel power plants are used as …………. plants.
(i) base load
(ii) peak load
(iii) standby
(iv) none of above

Sunday, 17 July 2016

Synchronous Motors - Multiple Choice Questions

Synchronous Motors - Multiple Choice Questions Points : Synchronous Motors, multiple choice questions and answers, electrical objective type question answers, mcqs 1. A synchronous motor rims at speeds ranging from .............
(i) 1800 to 3600 r.p.m.
(ii) 3600 to 6000 r.p.m.
(iii) 150 to 1800 r.p.m.
(iv) none of the above

2. The rotor of a synchronous motor is excited with direct current while the motor …………..
(i) is at standstill (i.e. at starting)
(ii) approaches synchronous speed
(ii) approaches half synchronous speed
(iv) none of the above

3. A synchronous motor runs at only one speed (i. e. synchronous speed) because it ………………
(i) has no losses
(ii) is a doubly fed machine
(iii) has a damper winding
(iv) none of the above

Sunday, 3 July 2016

Alternators - Multiple Choice Questions

Alternators - Multiple Choice Questions Points : Alternators MCQs, multiple choice questions and answers, electrical objective type question answers, mcqs
  1. Majority of the alternators are

    (i)single phase
    (ii)Three phase
    (iii)Two phase
    (iv)none of the above
  2. Armature windings of an alternator are generally

    (i)closed windings
    (ii)open windings
    (iii)partly open and partly closed windings
    (iv)none of the above
  3. The salient-pole construction for field structure of an alternator is generally used for ______ machine

    (i)2-pole
    (ii)4-pole
    (iii)8-pole
    (iv)none of the above

Tuesday, 31 May 2016

Single Phase Motors - Multiple Choice Questions

Single Phase Motors - Multiple Choice Questions Points : single phase motors, multiple choice questions and answers, electrical objective type question answers, mcqs
  1. The full-load efficiency of a shaded pole motor is about ……………

    (i) 70 to 80%
    (ii) 60 to 70%
    (iii) 30 to 35%
    (iv) 5 to 10%
  2. A vacuum cleaner employs motor.

    (i) resistance split-phase
    (ii) capacitor-start
    (iii) shaded-pole motor
    (iv) single-phase series motor
  3. The direction of split-phase induction motor can be reversed by interchanging the connections of supply of ............

    (i) either main or starting winding
    (ii) both main and starting winding
    (iii) rotor winding
    (iv) none of the above

Wednesday, 9 March 2016

Three Phase Induction Motor - Multiple Choice Questions

Three Phase Induction Motor - Multiple Choice Questions Points : three phase induction motor, multiple choice questions and answers, electrical objective type question answers, mcqs 1. In a 3-phase induction motor, the rotor speed is ……… the synchronous speed.
(i) greater than
(ii) smaller than
(iii) equal to
(iv) none of the above

2. A 4-pole, 50 Hz induction motor operates at 5% slip. The frequency of e.m.f. induced in the rotor will be ..............
(i) 25Hz
(ii) 50Hz
(iii) 2.5 Hz
(iv) none of the above

3. The air-gap between stator and rotor of a 3-phase induction motor ranges from …………
(i) 2 cm to 4 cm
(ii) 0.4mm to 4 mm
(iii) 1 cm to 2 cm
(iv) 4 cm to 6 cm