Skip to content
EndsemMay 20252019 patternSE Electrical

Electrical Machines-1 SPPU Endsem Question Paper May 2025

All 8 questions from this SPPU endsem paper, as printed. Read them here or open the PDF.

Open the PDFMost repeated Electrical Machines-1 questions
Subject code
203146
Pattern
2019 pattern
Exam
Endsem
Session
May 2025
Max. marks
70
Time
2½ Hours
Semester
IV
Paper code
[6402]-17

Printed for: S.E. (Electrical Engineering)

Instructions to the candidates

  1. Answer Q.1 or Q.2, Q.3 or Q.4, Q.5 or Q.6, Q.7 or Q.8,
  2. Neat diagrams must be drawn whenever necessary.
  3. Figures to the right indicate full marks.
  4. Assume suitable data, if necessary.
  5. Use of non-programmable calculator is allowed.

Questions

  1. Q1

    1. a)

      Compare simple Lap & wave winding.

      [4]
    2. b)

      Draw the power flow diagram of DC motor.

      [6]
    3. c)

      This part has equations that don’t show as text. Open the PDF to read it.

      [8]

  2. Q2

    1. a)

      State the parts of Stator & Rotor of DC machine.

      [4]
    2. b)

      Derive the equation for : i) Armature torque & ii) Shaft torque of DC motor

      [6]
    3. c)

      Draw the connection diagram of shunt , series & separately excited DC motors. State their current & back emf equations. 2

      [8]

  3. Q3

    1. a)

      Stale any two applications of- i) DC shunt ii) Series & iii) Cumulative compound motor

      [3]
    2. b)

      Sketch & explain the Torque- Armature current characteristics of i) DC shunt motor & ii) Series motor.

      Also asked:Nov 2025 ·May 2024 ·Nov 2023

      [6]
    3. c)

      A 220 V DC series motor takes 40 A when running at 700 rpm. Calculate the speed which motor will run & current taken from the supply if the field is shunted by resistance equal to field resistance & torque is increased by 50 %. Take R a = 0.12  & R se = 0.1  . Assume unsaturated magnetic field.

      [8]

  4. Q4

    1. a)

      State the possible ways to reverse the direction of rotation of DC shunt motor.

      [3]
    2. b)

      Sketch the circuit diagram & explain the methods of speed control of DC series motor by flux control.

      Also asked:May 2024 ·Nov 2023

      [6]
    3. c)

      Draw the connection diagram of 3 point starter used for DC shunt motor & explain the function of i) Hold on coil & ii) Over load coil

      Also asked:May 2024

      [8]

  5. Q5

    1. a)

      Draw the power flow diagram of 3-ph Induction motor.

      Also asked:Nov 2023

      [4]
    2. b)

      Prove that; rotor Cu loss = slip x rotor input.

      [6]
    3. c)

      A 30 kW, 4P, 50 Hz, 3-ph Induction motor has stator losses equal to rotor losses & rotatiodal losses of 1.5 % of output power. Full load slip is 4 %. Calculate; i) Rotor Cu loss ii) Rotor input power iii) Efficiency 3

      [8]

  6. Q6

    1. a)

      Calculate the slip & frequency of rotor current of a 3-ph, 50 Hz induction when running at 720 rpm.

      [4]
    2. b)

      Obtain the torque equation of induction motor under running condition & there of derive the condition of maximum torque.

      Also asked:May 2024

      [6]
    3. c)

      Sketch the family of torque-slip characteristics of 3-ph induction motor & explain i) operating region ii) maximum torque & iii) when slip is one

      Also asked:May 2024

      [8]

  7. Q7

    1. a)

      State the types of starters used for induction motors.

      Also asked:Nov 2025 ·Nov 2023

      [3]
    2. b)

      Demonstrate the IS Std 325 for testing of 3-ph induction motor.

      [6]
    3. c)

      Draw the connection diagram of star-delta starter & explain the starting and running operation of 3-ph induction motor.

      Also asked:May 2024

      [8]

  8. Q8

    1. a)

      Obtain the approximate equivalent circuit diagrams of 3-ph induction motor step by step. Label it & state the meaning of each nomenclature used.

      [7]
    2. b)

      This part has equations that don’t show as text. Open the PDF to read it.

      [10]