UNIT I DC GENERATORS Period
Basics of Electromagnetism – Overview of DC Generator – Importance of DC
generators in power generation and various industries – Types of DC generators –
EMF equation – Simple Problems – Internal and External characteristics –
Applications – Process of building up of EMF – Critical field resistance – Causes of
failure to build up voltage and remedies – Analysis of armature reaction effects –
Commutation process – methods of improving commutation.

UNIT II DC MOTORS Period
Overview of DC Motors – Significance of DC Motors in various industries and
automation – Types of DC Motors – Torque equation – Simple problems – Load
characteristics – Torque – Speed characteristics – Applications – Necessity of
starters – 3 point and 4 point starters – Speed Control of DC Motors – Losses,
Efficiency and regulation of DC Motors – simple problems – Special DC Machines:
BLDC Motor, Servomotor, PMDC Motor, Stepper motor.

UNIT III SINGLE PHASE TRANSFORMERS Period
Introduction to Transformers – Transformer Ratings – Applications – EMF Equation
– Problems – Ideal Transformer – No-load and Load Phasor Diagrams at Varying
Power Factors – Determination of equivalent circuit constants – Voltage Regulation,
Losses and Efficiency – simple problems –Condition for maximum efficiency – All
day efficiency – problems- Parallel operation of single-phase Transformer – Auto
Transformer – Comparison between two winding transformer and Auto transformer.

UNIT IV THREE PHASE TRANSFORMER Period
Three Phase Transformer – Construction and Types of connections of transformer
– Parallel operation and grouping of three phase transformers- Cooling of
transformers – Various cooling arrangements – Transformer accessories:
Conservator, Breather, Explosion vent, Buchholz relay –ON load and OFF load tap
changer.

UNIT V MAINTENANCE OF DC MACHINES AND TRANSFORMERS Period
Importance of Maintenance – Preventive and Breakdown Maintenance – Causes of
Sparking in Commutator – Defects in Commutator and Remedies – Resurfacing of
Commutator and Brushes – Defects in DC Armature winding – Maintenance of
Transformer Oil – Transformer oil tester – Acidity test, BDV test – Earthing –
Measurement of earth resistance.