(SEM IV) THEORY EXAMINATION 2021-22 ELECTRICAL MACHINES-I

SECTION A — Short Descriptive Paragraph Required

Section A asks brief theory questions on topics like electromechanical energy conversion, magnetic field coupling, dc machine starter, armature winding pitches, dc motor speed factors, types of dc motors used in cranes, transformer limitations on DC, vector groups, and transformer types.
Your answers must be short paragraphs clearly describing the meaning of the concept.

Extra sample questions:
Explain torque equation of DC motor in a short paragraph.
Describe the purpose of interpoles in DC machines.
Explain the need of a starter in DC shunt motor briefly.

SECTION B — Medium Descriptive Paragraph Required

contains detailed questions such as magnetic force derivation, armature reaction with sketches, characteristics of shunt and series motors, transformer efficiency calculations, and open-delta connection explanation.
Each answer must be one clear paragraph explaining the working, formula, steps, or reasoning.

Extra sample questions:
Describe flux control method of speed control in DC motor.
Explain hysteresis loop and its significance in magnetic materials.
Write a descriptive paragraph on autotransformer working.

SECTION C — Long Description Paragraph Required

 contains long theoretical and numerical questions such as energy–coenergy relationship, commutation, EMF and torque equations, speed control methods, Hopkinson’s test, OC–SC tests, transformer parameters, types of 3-phase transformer connections, and parallel operation conditions.
Each answer must be written as one long continuous paragraph, explaining diagrams, formulas, steps, or derivations.

Extra sample questions:
Explain the complete procedure of Swinburne’s test in a descriptive paragraph.
Describe transformer voltage regulation in detail.
Explain the working and construction of a single-phase transformer in long paragraph form.