Theory Examination (Semester-IП) 2015-16 BASIC ELECTRICAL ENGINEERING

This question paper checks a student’s understanding of basic electrical circuits, AC fundamentals, power measurement, transformers, DC machines, induction machines, synchronous machines, and electrical instruments.
It is divided into three sections—definitions, numericals, and long descriptive questions.

SECTION – A (10 × 2 = 20 Marks)

This section contains brief conceptual questions.
Topics include:

Active vs passive elements

Maximum power transfer with internal resistance

R.m.s. value & frequency of sinusoidal current

Active, reactive & apparent power

Power factor in two-wattmeter method

Non-linear scale of MI instruments

Air-gap flux and ampere-turns

Transformer resistance referred to primary

Torque–speed characteristics of DC series motor

Slip–torque characteristics of induction motor

This part tests fundamental electrical engineering concepts.

SECTION – B (5 × 10 = 50 Marks)

Students must solve any five medium-length questions including circuit analysis, diagrams, and calculations.
Topics include:

Loop analysis for current calculation

Average & RMS value of a given voltage waveform

Torque–speed diagram of DC series motor

Slip–torque characteristics of induction motor

Resonance in series RLC circuits & resonant frequency

Three-phase delta-connected coils: current, power factor & total power

Construction & working of PMMC instrument

Transformer losses, efficiency & maximum-efficiency condition

DC shunt motor: induced EMF, currents, power & torque

Magnetic circuit terms like MMF, reluctance & flux density

This section tests problem-solving ability, diagrams, and conceptual clarity.

SECTION – C (2 × 15 = 30 Marks)

Students must attempt any two long-answer questions.

Topics include:

Maximum Power Transfer Theorem

Statement, proof, and numerical application

Single-Phase Induction Motor

Non-self-starting nature (double revolving field theory)

Capacitor-start and capacitor-run methods

Applications

Three-Phase Synchronous Motor

Why it is not self-starting

Role of damper winding

These questions evaluate deep understanding, derivations, diagrams & machine theory.