B.TechSemester 42023-24Electrical Machines IBEE402

Electrical Machines I (BEE402) - AKTU Question Paper 2023-24

B.Tech · Semester 4 · Free PDF Download

This is the official AKTU Electrical Machines I Previous Year Question Paper for B.Tech Semester 4, academic session 2023-24. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.

Course:B.Tech

Semester:Semester 4

Session:2023-24

University:AKTU / UPTU

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Questions Asked in 2023-24

Electrical Machines I (BEE402) — complete question paper · 70 marks · 3 Hours

Section A

a
Explain principle of electro-m echanical energy conversion with the help of block diagram
b
Define energy and co-energy in a linear magnetic system
c
Describe working of commutator in a DC machine as mechanical r ectifier
d
Write the emf equation of D C Motor. Explain each term
e
Discuss the need for starters in the operation of DC motors
f
Draw phasor diagram of ideal transformer at no load condition
g
List the conditions f or parallel operation of transformers

Section B

a
Show that the field energy in a linear magnetic system is given by
b
With the help of neat sketch, explain armature reaction in DC machine
c
Explain in detail the speed control of DC motor by (i) Armatur e Control Method and (ii) Field Control Method
d
The maximum efficiency of a 100 kVA, 1100/440 V, 50 Hz transfo rmer is 96%. This occurs at 75% of full load at 0.8 power factor lagging. Calculate the efficiency of transformer at half load and at 0.6 power factor lagging
e
Discuss various types of connections employed in 3-phase trans formers

Section C

a
Derive an expression for Reluctance torque in rotating elec trical machines
b
For a doubly excited linear ma gnetic system, derive an expr ession for the electromagnetic torque. 4 . A t t e m p t a n y one part of the following: 7 x 1 = 7
a
Explain the construction and working of DC machine with well-labelled diagram
b
Draw the internal and external characteristics of the DC sh unt generator. Also, explain (i) why the external characteristics turn backwards (ii) concept of vol tage build-up and critical field resistance in DC shunt generator. 5 . A t t e m p t a n y one part of the following: 7 x 1 = 7
a
Explain Swinburne’s test to calculate no-load losses in a DC machine. State its limitations over Hopkinson’s test
b
With the help of neat diagram, explain the working of 3-poi nt starter. What are its limitations? How are these limitations overcome by 4-point starter? 6 . A t t e m p t a n y one part of the following: 7 x 1 = 7
a
A 200 kVA, 2000/440 V, 50 Hz, single phase transformer gave the following test results: O.C Test (hv) : 2 kV, 1.75 kW, 1.8 A S.C Test (lv) : 13 V, 1 kW, 300 A (i) Calculate the parameters of equivalent circuit as referred to H.V side (ii) Determine voltage regulation and efficiency at full-load, 0.8 power factor lagging
b
Draw and explain the complete equivalent circuit model of a practical transformer. Also, draw phasor diagram of practical transformer on-load condition at lagging power factor. 7 . A t t e m p t a n y one part of the following: 7 x 1 = 7
a
Describe the 3-phase to 2-ph ase conversion in transformers with suitable diagram. Also, derive the expression for positioning of neural point
b
What is V-V connection? Show that the open delta connection has a kVA rating of 57.7% of the rating of the normal delta-delta connection

Question text is extracted from the official AKTU question paper PDF above. Hindi translations are omitted — every question is printed in English in the original paper. Last verified: 2026-08-23.

Repeated Questions — BEE402

Questions that appeared in more than one session, found by comparing 3 years of Electrical Machines I papers (2023-24, 2024-25, 2025-26)

List the conditions f or parallel operation of transformers

Appeared in: 2023-24 · 2024-25 · 2025-26

The maximum efficiency of a 100 kVA, 1100/440 V, 50 Hz transfo rmer is 96%. This occurs at 75% of full load at 0.8 power factor lagging. Calculate the efficiency of transformer at half load and at 0.6 power factor lagging

Appeared in: 2023-24 · 2024-25 · 2025-26

What is V-V connection? Show that the open delta connection has a kVA rating of 57.7% of the rating of the normal delta-delta connection

Appeared in: 2023-24 · 2024-25 · 2025-26

Draw phasor diagram of ideal transformer at no load condition