Machine-translated by Google. Questions are authored in English.
Top

MPSC AE 2023: Maharashtra Electrical Engineering Services Main Examination, Paper 1

  • Paper code: 123
  • Language: Bilingual
  • 8 pages
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 1 of 8
Page 1 of 8
Text of page 1
rr€Eirtr W srBrrr6# +E-r (W) rr$Sf - loe3 , r? . .ta ,1)mff.?orf
                                                                              r+n< -L)
                                                                             t
     ffi                                          2023                                 418
                                                                                  BOOKLET NO.


                                                                                   300101
-
                                  Electrical Engineering
                                              Paper - I


     Time Allowed: Three Hours                                                Maximum Marks : 200
     Medium: English                                                 Type of Paper : Conventional

                                 Question Paper Specific fnstruetions

     Please read, eoch of the follouting inetructions corefully before attempting
      question:
                                                                                                          F]
        1. There are EIGHT questions divided in two Sections, out of which FIVE are to be
                                                                                                          FI
            attempted.
        2. Questions no. 1 and 5 are compulsory. Out of the remaining questions, THREE are to be
                                                                                                          a
            attempted ehoosing at least ONE question from each Section.
        3. The number of marks carried by a question/sub question is indicated against it.
        4. Keep in mind the word limit indicated in the question if any.
        5. Wherever option has been given, only the required number of responses in the serial order
            attempted shall be assessed. Unless struck off, attempt of a question shall be counted
            even if attempted partly. Excess responses shall not be assessed and shall be ignored.
        6. Candidates are expected to answer all the sub-questions of a question together. If
           sub-question of a question is attempted elsewhere (after leaving a few page or after
           attempting another question) the later sub-question shall be overlooked.
        7. Any page or portion of the page left blank in the Answer Booklet must be clearly struck off.
        8. Unless otherwise mentioned, symbol and notation have their usual standard meanings.
            Assume suitable data, if necessary and indicate the same clearly.
        9. Neat sketches may be drawn, wherever required.
       10. The medium of answer should be mentioned on the answer book as claimed in the
            application and printed on admission card. The answers written in medium other than
            the authorized medium will not be assessed and no marks will be assigned to them.
     Note - 1. Candidates will be allowed to use Scientific (Non-programmable type)
                  calculators.
                                                                                                P.T.O.
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 2 of 8
Page 2 of 8
Text of page 2
f-




                                                2                                      Q18
     HH
                                          SECTION -A
                                                                                               a

                                                                                                   t
                                                                                               t

           Answer any five of the following :
                                                                                                   I
     Q1.                                                                            (8x5=40)
           (a) A periodic voltage waveform has been shown in Fig. 1.0. Determine the
                following:
                 ,) Frequency of the waveform
                ii) RMS value
               ii, Average value
               lv) Form factor.                                                                    t

                   10v
                                                                                               i
                                                                                                   I
                                                                                                   t
                   5V
                                                                                                   l
                                                                                                   I
I
                                                                                                   t



                                          100                         200
                                                                 t(m sec)

                                            Fig. 1.0

           O) Find the z-parameters for the network shown in Fig. 2.0.

                         a        5kC}              d            3kCl r,    e
                                                                                +
                         t I,                                               t                          a




                         V1                             12 kCI              Y2                             !



                         T
                             b                      c                       f

                                            Fig. 2.0
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 3 of 8
Page 3 of 8
Text of page 3
3                                        Ql8
      HH
           (c) Obtain the current i, using KVL for the circuit shown in Fig. 3.0
                               ,1

                                    10C,                     5C,
                                                                               +
                             5C)                        1O           10C,          10v
                                     5A
.,                10A



                                            Fig.3.0
           (d) State and discuss the Coulomb's law and Gauss's law.
           (e) State and discuss the Biot-Savart law and Ampere's circuital law.
           (f) A single phase 4I{VA, 200 V/100 V, 50 Hz transformer with laminated CRGO
                steel core has rated no-load loss of 450 W. When the high voltage winding is
                excited with 160 V, 40 Hz sinusoidal AC supply, the no-load losses are found
                to be 320 W. When high voltage winding of the same transformer is supplied
                from a 100 V, 25 Hz sinusoidal AC source for this condition determine the
                no-load loss of the transformer.
           G) A single phase, 2000 V alternator has armature resistance and reactance of
                0.8 ohms and 4.94 ohms respectively. Determine the voltage regulation of
                the alternator at 100 A load and 0.8 leading power factor.

      Q2. (a) Use Thevenin's theorem to determine the power loss in 10 C) resistance of
                the circuit given in Fig. 4.0.                                              lE
                                                     10Ct          2{'
 .l




             2A
                   t                                                         t 5A

                                             Fig. 4.0


                                                                                         P.T.0.
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 4 of 8
Page 4 of 8
Text of page 4
4                                      Q1s
HH
     O) In the Network shown in Fig. 5.0, L1 = 1 H; Lr= 2 H, M=1.2 H. Assume
        inductance coils to be ideal, determine the amount of energ'y stored after
        0.1 second of the circuit when 10 V DC source is connected across Lr.    15
                                                     iz
                          '1
                                             M
                                      a    4-l       a
                    1
                   10v              L,               L,




                                      Fig.5.0
     (c) Determine the energJr stored in a system of four identical point charges of
         Q = 5 nC at a corners of a square 1 meter on a side. Determine the energ:y
         stored in the system when only two charges at opposite corners of the square
          are present.                                                               10
QS. (a) The magnetic circuit shown in Fig. 6.0 has uniform cross-sectional area and
          air gap of 0.2 cm. The mean length of the core is 40 cm. Assume that leakage
          and fringing fluxes are negligible when core relative permeability is assumed
          to be infinite, the magnetic flux density computed in the air gap is 1 tesla
          with same ampere-turns if the core relative permeability is assumed to be
          1000 (inear). Calculate the flux density in the aiq gap.
                         rl
                         '4-       10cm          #
                                                                                      15



                         l-                                -]

          I              I




                         L                                 J

                                          Fig. 6.0
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 5 of 8
Page 5 of 8
Text of page 5
7
                                            D                                         Q18
H#
     (b) A 230 Y, 25O rpm, 100 A separately exeited DC motor has an armature
         resistance of 0.5 Q. The motor is connected to 230 V DC supply and rated
         DC voltage is applied to the field winding. It is driving a load whose
         torque-speed characteristics is given by T, = 500 - 10 co, where co is rotational
         speed expressed in rad./sec and T, is load forque in Nm. Find the steady state
         speed at which the motor will drive the load and armature current drawn by
         it from the source. Neglect the rotational losses of the machine.               15
     (c) Two identical synchronous generators each of 100 MVA, are working in
         parallel supplying 100 MVA at 0.8 lagging pf at rated voltage. Initially
         the machines are sharing load equally, if the field current of 1sr generator
         is reduced by 5o/o and of second generator is increased by 5%. Determine
         the sharing of load (MW and MVAR) between the two generators. Assume
         Xd = X. = 0.8 PLI, no freld saturation and rated voltage across the load.
         Reasonable approximation may be made.                                           10

Q4. (a) Find the voltage drop across 4 Q and 10 Q resistors for the circuit shown in
          Fig'7.0, using mesh current analysis.                                         15
                                 4{2




                                         20
                v(^") 50 /30"                                    10Cl


                                         j5C,




                                      Fig.7.0
     (b) A 50 HP, 6 pole SOHz slip ring induction motor runs at 960 rpm on full load
         with rotor current of 40 A. Allowing 300 W for the copper loss in the short
         circuiting gear and 1200 W for mechanieal losses, frnd R, @otor resistance
         per phase) of 3 phase rotor winding.                    -                 15
     (c) Three-phase, three winding NN Y (1.1 KV/6.6 I(V/400 V) transformer is
         energised from AC mains at the 1.1 KV side. It supplies 900 KVA load at
         0.8 power factor lag from the 6.6 I(V winding and 300 KVA load at 0.6
         power factor lag from the 400 V winding. Determine the RMS line current
         in Amperes drawn by the 1.1 KV winding from the mains.                    10

                                                                                     P.T.0.
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 6 of 8
Page 6 of 8
Text of page 6
6                                      Q18
HH
                                     SECTION- B


Q5. Answer any five of the following :                                          (8x5=40)
     (a) Draw and discuss the block diagram of Hydro-electric power plant. State the       A
                                                                                           t



          types of water turbines used in hydro-electric power plant.

     (b) The neutral of 10 MVA, 11 KV alternator is earthed through a resistance of
          5 ohm. The earth fault relay is set to operate at 0.75 A. The CT have a ratio
          of 1000/5. What percentage of the alternator winding is protected ?
     (c) Draw the zero-sequence equivalent circuit for following transformer
          configurations:
          r) Y - Y connections with both neutrals grounded.
         ii) Y - Y connection with the primary neutral grounded.
         iir) Y - A with grounded neutral.
         ,v) Y - A with isolated neutral.
     (d) Discuss solar PV cell on following points   :


          r) P.V. eell manufacturing technologies and cell effrciency.
          ii) I-V characteristics.
         ,r) P-V characteristics.
         iv) Equivalent circuit.
     (e) Define following terms and laws with reference to illumination    :


          ,) Lumens
         ii) Utilization factor
        iil) Space to height ratio
         w) Inverse square law
     (0 State and discuss the procedure for synchronization of DG set with utility
          supply. How the load sharing is adjusted ?



                                                                                               t
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 7 of 8
Page 7 of 8
Text of page 7
7                                         Q18
HH
     (g) In a medium sized engineering industry a 340 *3/h" reciprocating compressor
         is operated to meet compressed air requirement at 7 bar. The compressor is
         in loaded condition for 80% of the time. The compressor draws 32 KW during
         load and 7 KIil during unload cycle.
         After arresting the system leakages, the loading time of the compressor
         came down to 600/o.
         Calculate the annual energ:y saving at 6000 hours of operation per year.

Q6. (a) A three phase, 60 Hz, 500 KV transmission line is 300 km long. The line
          inductance is 0.97 mH/km per phase and its capacitance is 0.0115 pF&m
          per phase. Assume a lossless line.                                   15
          t) Determine the line phase constant p, the surge impedance 2", velocity of
             propagation o and the line wavelength 1,.
         iil The receiving end rated load is 800 MW, 0.8 power factor lagging at
             500 KV. Determine the sending end quantities and voltage regulation.
     (b) i) State the various types of energy storage systems. Discuss with block
             diagram, magnetic energy storage system.
          ii) Discuss smart grid on following points :
               ,) Architecture
              ii) Benefrts
             ,rr) Technologies associated with smart grid
              lv) Charaeteristics of smart grid.                                        15

     (c) An alternator is connected to an infrnite bus as shown in Fig. 8.0. It delivers
          1.0 PU current at 0.8 pf lagging at V = 1.0 PU. The reactance Xu of the
          alternator is 1.2 PU. Determine the active power output and steady state
          power limit. Keeping the active power fixed, if the excitation is reduced, find
          the critical excitation corresponding to operation at stability limit.        10


                l\\/l                                                   v- 1.0 /o
                                          xd
               E<6

                                       Fig. 8.0

                                                                                    P.T.O.
MPSC AE 2023 question paper, Maharashtra Electrical Engineering Services Main Examination, Paper 1, page 8 of 8
Page 8 of 8
Text of page 8
E                                        Q1s
                  H#
                  Q7. (a) A drawing han 30 metres by 13 metres with a ceiling height of 5 metres is
                            to be provided with a general illumination of 120 Iux. Taking a co-efficient
                            of utilization of 0.5 and depreciation factor of L.4, determine the number of
                            fluorescent tubes required, their spacing mounting height and total wattage.
                            Taking luminous efficiency of fluorescent tube as 40 lumens/watt for 80 watt
                            tube.                                                                        L5
                       (b) A centrifugal clear water pump rated for 800 -3/h" was found to be operating
                            at 576 mo/hr with discharge valve throttled. The pump speed is 1485 rpp.
                            The discharge pressure of the pump before the throttle valve is 2 kg/cmzg.
                            Pump draws the water from a sump 4 metres below the centerline of the
                            pump. The input power drawn by the motor is L24 KW at a motor efficiency
                            of 92o/o.                                                                     15
                             ,) Find the efficiency of the pump.
                            ii) If the normal required water flow rate is 500 -3/h, to 700 *3/h", what in
                                your opinion should be the most energJr efficient option to get the required
                                flow rate variation ?
(
                           iir) And what would be the pump shaft power for the mgst energy efficient
I
            F.l                 option if the pump is delivering the flow rate of 550 -3/h" ?
I

I
                       (c) Compare single phase online UPS with single phase offline UPS on following
                           points '
    I




x
    I
    I



        I
            a
            FI]
                            r) Detailed circuit diagram of both UPS.
                                                                                                    10

                            ii) Relative advantages and disadvantages.
                           rrr) Requirement of transfer switch.
                           iv) Applications.

                  Q8. (a) Discuss following relaying scheme for transmission line protection with relay
                            characteristics:                                                             1E
                            1) Over cunent relaying
                            ii) Distance relaying
                           iii) Pilot relaying.
                       O) Discuss operational factors for better efficiency in DG set and state the energy
                            saving measures for DG set.                                                  15
                       (c) state various types of fans and discuss flow control strategies.              10
Page 1 of 8

Source: Maharashtra Public Service Commission. Question paper published by Maharashtra Public Service Commission.

Other years

About Us

ExamsRepo

Copyright © 2026 ExamsRepo . All Rights Reserved . With