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InsemMar 20262019 patternSE Electrical

Electrical Machines-1 SPPU Insem Question Paper Mar 2026

All 4 questions from this SPPU insem 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
Insem
Session
Mar 2026
Max. marks
30
Time
1 Hour
Semester
IV
Paper code
APR-26/SE/Insem-247

Printed for: S.E. (Electrical Engineering) (Insem)

Instructions to the candidates

  1. Solve Q.1 or Q.2 and Q.3 or Q.4.
  2. Figures to the right side indicate full marks.
  3. Neat diagrams must be drawn wherever necessary.
  4. Assume suitable data if necessary.
  5. Use of non-programmable calculator is allowed.

Questions

  1. Q1

    1. a)

      What are the losses taking place in the transformer? Derive the condition for maximum efficiency of the transformer.

      [7]
    2. b)

      What is an autotransformer? Derive the equation for the saving of copper in the case of autotransformer as compared to two winding transformers along with the necessary diagram.

      [8]

  2. Q2

    1. a)

      With neat circuit diagram explains open circuit and short circuit tests on a single-phase transformer for finding the voltage regulation and efficiency of the transformer.

      [7]
    2. b)

      Sketch and explain the phasor diagram of the single-phase transformer at the ON load considering the effect of winding resistance and magnetic leakage.

      [8]

  3. Q3

    1. a)

      With proper connection and phasor diagrams describe the star/star connection of the three-phase transformer. Explain it in brief.

      [7]
    2. b)

      Two l00-kW, single-phase transformers are connected in parallel both on the primary and secondary. One transformer has an ohmic drop of 0.5% at full-load and an inductive drop of 8% at full-load current. The other has an ohmic drop of 0.75% and inductive drop of 2%. Show how will they share a load of 180 kW at 0.9 power factor. 2 APR-26/SE/Insem-247

      [8]

  4. Q4

    1. a)

      With the neat sketch and phasor diagram explain the V-V connection of the transformer.

      Also asked:Mar 2025 ·Mar 2023

      [7]
    2. b)

      State the necessity of parallel operation of the transformer. State any four necessary conditions for satisfactory parallel operation of the transformer. 

      Also asked:Mar 2025

      [8]