So here is the past paper for the Wapda junior Electrical engineer which was conducted by PTS testing agency. This Wapda past paper would help candidates get understanding what topics should be cover before appearing any electrical engineering tests. Most of these Wapda electrical engineer tests are from the subjects power electronics, basic power engineering,basic electrical engineering,control system and basic electronic engineering.
Past paper for wapda junior electrical engineer
or Engineer Past Paper NTDC
Q-1: Hollow conductors are used in transmission lines? Why because of skin effect which was not in options
Q-2: Shunt Reactors are needed to boost? To compensate for the leading power Factor they boost reactance
Q-3: GSM use which of the following multiplexing Technique? According to the examiner mentality answer
would be TDMA, otherwise in GSM each channel based on FDMA is subdivided using TDMA, and so both
FDMA + TDMA are used
Q-4: In a line ground fault system, fault current is 15 Amp, what would be zero sequence current? Do not know
answer
Q-5: To reduce cost of power generation? Answer: Load factor(higher/increase)+Diversity factor(higherincrease)
Q-6: In a transformer with no load condition? Voltage leads or lags behind and by what degree? Answer: Its perfectly in phase
Q-7: which of the following are predominant input losses in a no load transformer? Eddy losses/copper losses/windage losses? Answer: Since the word predominant is used I would opt for Eddy current losses
Q-8: In a DC machine what is the angle between rotor and stator fields? 45°/90°? Answer: its 90°
Q-9: A numerical with energy consumed by a heater given in joules, time given in second, also current drawn was given and voltage was asked?
Q-10: Why the pole tips are chamfered wound? Answer: In order to reduce concentration of flux at the leading pole tips: of a dyanamo
Q-11: What is the main task of power electronics ? ac-dc/ac-ac/dc-ac conversion? Answer: Ac-Ac Conversion
Q-12: Flyback converter is used to? Answer: It is used in both ac-dc and dc-dc conversion
Q-13: Series capacitors are used in transmission line to? Answer: for voltage regulation
Q-14: load convey capacity of AC line is limited by ? Answer: size
Q-15: AMPS use which of the following multiplexing technique? Tdm/fdm/cdm? Answer: FDMA
Q-16: Orthogonal coordinate system has? Parallel/perpendicular? Answer: This system has surface that meet at right angle so the answer is Perpendicular
Q-17: TDMA uses which of the following technique? Answer: Time division technique
Q-18: laplace Transfer of unit step function is? s or 1/s? Answer: 1/s
Q-19: Torque of induction motor is proportional to? Slip/current? Answer: I think its directly proportional to slip
Q-20: Which motor has the highest torque? Series/dc/shunt? Answer: Series Dc Motor
Q-21: Motor that should not be used with load removed? Answer: Series Motor again
Q-22: An Ideal voltage source has? Answer: 0Ω Resistance
Q-23: An Ideal current source has? Answer: ∞Ω Resistance i-e opens circuited resistance
Q-24: Two questions related to mercury arc rectifier?
Q-25: Sensors in industry send data in analog form, and before feeding them to system, which of the following converts them to digital? Of course it was ADC (analog to digital converter)
Q-26: One question was from transistor biasing technique that discussed property of a particular technique
Q-27: What is power factor? Real power/Apparent power
Almost 5 questions were from control engineering that talked about, if inputs are zero than state response is
what?, other were related to nature of poles and zeros? And planes?
Junior Engineer Past Paper Gepco Technical Portion
18. Low resistance measuring device is Kelvin Bridge.
19. The shunt winding of motor has a resistance of 85 ohm at 22 degree when the motor runs at full load, its resistance increases to 100 ohm. The resistance temperature coefficient of winding per 0 degree is 0.004. The rising temperature of winding will be? Ans is 70 degree.
20. A 100V bulb has a resistance of 500 ohm. The number of hours it can work per every KWh of energy consumed will be ? 50 hours.
21. Main feature of crystal oscillator is stability. (2 Times repeated)
22. In class A, conduction angle is 360 degree.
23. For pre amplification, which Power amplifiers are used for linearity purpose? Class A, Class B, Class C, Class A-B.
24. In metals, electrons revolve in the metal because of (constant V, sinusoidal, square, triangular, non periodic).
25. Moderator used in Nuclear is graphite.
26. In alternator, if p.f load is unity, then armature flux will be? cross magnetizing.
27. State variables are used in which models? All of above.
28. LTI system can be completely recognized by impulse response of the system.
29. Stray Voltage is small voltage (less than 10) which can be measured between two points.
30. At resonance, Current is ? Reactance is zero, and one’s answer is none of above. (3 MCQS)
31. Stepper motor, speed depends upon frequency.
32. There are two types of overload protection: instantaneous overcurrent and time overcurrent
33. In motor which O.L protection is used ? Thermal O.L relay.
34. Vrms*Irms=Apparent Power
35. Power against Inductance is reactive power.
36. Power against resistance is active power.
37. If all conductors are grounded to the same grounding system, what is the probability of shock?
(Minimum ? Zero? What?)
38. CMMR =
39. CMMR should be (low, maximum, high, zero) for better OPAM operation.
40. Uranium-235 is an isotope of uranium making up about 0.72% of natural uranium
41. Thermal to K.E is converted in the Rocket.
42. Moving iron type Ammeter has few turns of thick wire so that its resistance is less.
43. The advantage of permanent magnet ammeter is all of above. (effective eddy current damping,
low hysteresis loss, low power consumption, uniform scale, very sensitive to current.)
44. If height of transmission tower is increased, Capacitance will decrease and inductance remain same.
45. For current amplification, CC & CE are used.
46. VI characteristics of UJT is similar to ?
47. CB is similar to Common gate of FET.
48. TRIAC is bidirectional device.
49. Solid grounding is used below 660V.
50. In submarine power is transmitter through which cables (
51. Which is least reliable source of energy? (wind)
52. High gain DC-DC convertor applications are ? (All of above)
53. Which principle is used to analyzing the fault? (Thev, nort, Superposition, Jordon).
54. Q-point operating point of transistor model analysis.
55. Negative resistance is of Tunnel diode.
56. Inverse of p.f is Q factor.
57. Roll off rate of operational amplifier is usually is -20 dB decades.
58. Channel is in b/w Drain and Source of FET.
59. Which current flows due to minority charge carriers? (Hole current, reverse leakage
current, forward leakage current, all of the above.)
60. Transformer rating is given in KVA instead of KW why? (Customary, loss depends upon V&I, power factor is not known, All of above).
61. In Transformer ratio 20:1 means
62. Stator appears to be stationary and rotor freely moves which is rotating transformer is
equivalent to induction motor.
63. Transformer has maximum efficiency when Cu losses becomes equal to Fe losses.
64. In transformer leakage flux is proportional to current which indicates (leakage flux in core some sort of MCQs)
65. Transformer has different no. of primary & secondary turns.
66. Which op amp converts high impedance to low impedance (inverting, non inverting, follower, summing point)
67. On reverse biasing of FET, what happens? (Channel resistance increase? Or Capacitance?)
68. SCR goes into saturation when (gate to cathode voltage forward biased?)
69. CE amplifies (V, I, P, all of above)
70. DC motor has high torque.
71. Accumulative motor adds the series and shunt magneto motive force.
72. Control system is used for? (remote control, power application, disturbance control, all of above)
73. Which does not use external source ( Oscillator)
74. OP AMP optimum operating voltages are ( +_18, +_15, etc)
75. LC Tuned oscillator stability is dependent upon (Q factor, L, C, transistor).
76. Light is produced in electric discharge lamp due to (heating effect, magnetic effect, ionization ina gas / vapor).
77. What is produced by superconductor (V, temp, Press, magnetic field)
78. In superconductors what happens ( repulsion of magnetic, absorbing of magnetic field,
absorbing of electric field, repulsion of electric field)
79. Which engine has highest air fuel ratio?
80. Diode is used for rectification.
81. Diode limiters are used for limiting positive and negative cycles both.
82. In Bridge s, ripple frequency of output wave is twice of input.
83. Voltage controlled oscillators:
84. Lead acid batteries are storage batteries
85. Output variables are (Dependent, independent so, so) dependent.
86. Current leads by 90 and voltage lags by 90 to current is in ©
87. If poles lie in left half plane, system is stable.
88. Which power system requires 4 wires? (star, delta, interconnected, none of above)
89. Current in transmission lines is .......(3 phase)
90. DC two wire system require least conductor material.
91. 3 phase 4 wire system has two types of voltages
Junior Engineer Wapda Past paper
1. Vertex is also called=Node
2. When the current in the light bulb decreases by 2%, its power decreases by =4%
3. What is transformer part Primary coil secondary coil & = Core
4. Electric lines of force about negative point charge are =radial inwards
5. Which is Semiconductor Switch = Thyristor
6. How Thyristor is turned off= Forced Commutation
7. Protection relay used are =Instantaneous and Time Over current
8. Current transformer is used with Protection device for measuring = Current
9. Which is not Part of Steam Turbine? Moderator, Economizer, Precipitator
10. Diode Operation voltage = 0-0.7v
11. Power Plants run on Natural Gas, Steam coal, etc. are =Fossil Fuel Plants
12. Which Plant do not used Heat Exchangers or turbines= Geothermal
13. steam power plant flow chart or something how many steps=4
14. In a generator of 60 HZ and 10 Pole what will be N Speed = 120*60/10=720
15. In a Substation where no transformer is? Switching Substation
16. high frequency application we use --Air core Transformer
17. Sin wave is characterized by? Amplitude, Frequency & Phase
18. Dynamic Disturbance Recorders (DDRs), which record incidents that portray power
system behavior during dynamic events such as low-frequency = (0.1 Hz - 3 Hz)
oscillations and abnormal frequency or voltage excursions
19. Induction motor rotor are Squirrel cage and Wound type = Squirrel Cage (Both)
20. A sinusoid is represented by = Phasor
21. If there are less than 4 free electron then its =Conductor
22. Which is Not a substation = Line Substation
23. Which is not at type of Thyristor? = inverter Grade
24. Efficiency of thermal plant =33-48%
25. What is basic principle behind motor operation? =electromagnetism
26. Induction motor is similar to=asynchronous
27. Synchronous generators are used, because they offer precise control of voltage,
frequency, VARS, watts.
28. Voltage Regulation in generation voltage?
29. SEIMENS is unit of = Conductance
30. System protection devices which includes? A)Reliability, B) selectivity, C) cost, D) Speed,
E) Simplicity
31. 2 types of Exciters? 1. Rotating 2. Static
32. Which transformer is used in arc welding???? Leakage
33. When admittance increases current increases or Decrease? Increase
34. Power switch is characterized into how many groups? 3
35. Stator core is made of many thin metal sheets called? lamination
36. Most squirrel cage rotor is made by die casting of? Aluminum conductor bars
37. All process system consists of three main factor or term? Variable, control variable
and uncontrolled
38. The sensitivity of measurement is a measure of the change in the instrument output,
which occurs when the quantity being measured changes by a given amount.
39. The sensitivity of measurement is a measure of the change in the instrument output,
which occurs when the quantity being measured changes by a given amount.
40. Substation transforms voltage from high to low And reverse and perform many of the
several important functions
41. The input for a distribution substation is typically at least two transmission or sub
transmission lines
42. Generators are cooled by? Air-water cooled , Fins
43. A process control system consists of process, measurement control: = Analysis
44. Generator voltage is determined from excitation is? island operation
45. The matrix obtained by deleting the column corresponding to the reference node in the
element node incidence matrix A is called bus incidence matrix A
46. Stainer is used to prevent foreign particles to reach turbine along with steam.
47. __________is used for emergency stop of steam along? throttle valve
48. Complex quantities in power system are represented by? Phasor
49. When a small resistance or impedance is accidentally or intentionally inserted b/w two
points of different potential, it is called short circuit
50. The loss in a T/F due to reversal of direction of current is called? Hysteresis loss
51. The frequency of generator depends on? speed and no of poles
52. Higher efficiency can be obtained at higher temperature, this is dictated by? Carnot
efficiency
53. The boiler in which tubes are placed in a horizontal cylinder is called? horizontal, fin
tube
54. Reactive power at load determine by.......? field current heating
55. Magnetic density circuit is increased by? increasing no of turns
56. A circuit breaker which can be separated from the circuit without interruption in the
circuit because of additional contacts is called? (Removable/Separable CB/Disconnector)
57. The study of disturbances on power system during abnormal operating conditions is
called? Load Flow Analysis
58. Equipment with capacity to work within range? circuit breaker making capacity
59. Intercepting contacts of circuit breaker is a set of contacts which enable circuit breaker to be removed? a) Withdrawal b) discontinue c) plug in d) current limiting e) Moulded case
60. Sinusoidal voltage and current at constant frequency is characterized by 2 parameters, a
max value and --------? a) angle b) value of load angle c) R value d) load angle
61. Which one is not a transformer? 1) Laminated 2) resonance 3) single instrument
transformer 4) ferrite circuit transformer 5) caste iron transformer.
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