DIPLOMA COURSE IN ELECTRICAL AND ELECTRONICS ENGINEERING
Sub: ELECTRICAL MACHINES – II
Contact Hrs/Week: 4. Contact Hrs/Sem: 64
Chapter No Topic No. of Hours
1 Transformers 22
2 Induction motors 20
3 Synchronous motors 10
4 Single phase motors 2
Industrial innovation 6
Tests and Revision 4
1. TRANSFORMERS 22Hrs
1. Working Principle of Transformer 4
2. E.M.F. Equation. 3 3. Operation on No Load & On Load 1
4. Equivalent Circuit 1
5. Regulation & Efficiency 6 6. Three Phase Transformers 2
7. Cooling of Transformer 2 8. Welding Transformer 1
9. Auto Transformer 1
10. Parallel Operation 1
2 Induction motors 20Hrs
1. Working principle 3
2. Types: Types of induction motor and their construction details. 1
3. Torque: Torque-slip curves. 4
4. Equivalent circuit 1
5. Power output 2
6. Circle diagram: No load and blocked rotor tests-construction of circle
diagram-problems. 3 7. Starting: Necessity & Types, soft starters. 2
8. Speed Control: Different methods 2
A] Change of applied voltage B] Change of frequency C] Change of poles D] Rheostat control
9. Linear induction motor 1
10. Induction generator 1
3 Synchronous motors 10Hrs
1. Working principle. 2
2, Operation on load 1
3. Characteristics 2
4. Hunting 1 5.Starting Method: 1
6. Applications 1
7. Permanent magnet synchronous motor 2
NEODYMIUM, SAMARIUM, COBALT, FERRITE, ALNICO.5
4. Single phase Motors 2Hrs
Split phase motors and Capacitor motors
SPECIFIC INSTRUCTIONAL OBJECTIVES
1.1 Working principle, construction and classification
1.1.1 Explain the working principle of transformers.
1.1.2 Classify the various types of transformers
126.96.36.199 Based on construction
188.8.131.52 Based on application
1.1.3 Explain briefly the various parts of the transformer and explain the functions
of each part.
1.1.4 Name the different insulating material used in transformer.
184.108.40.206 Write the properties and uses of transformer oil.
1.1.5 Explain the construction of core type and shell type transformers.
1.2 Emf Equation
1.2.1 Derive emf equation and explain transformation ratio.
1.2.2 Solve problem on emf equation.
1.3.1 Explain the operation of a transformer on no load and on load with vector
1.3.2 Solve the problem on transformer on no load.
1.4 Equivalent circuit
1.4.1 Define the equivalent resistance of a transformer as refereed to primary and
1.4.2 Explain magnetic leakage in a transformer core.
1.4.3 Explain leakage reactance & calculate equivalent reactance as referred to
primary and secondary side.
1.4.4 Write the formula for equivalent impedance.
1) Referred to primary. 2) Referred to secondary
1.4.5 Draw the equivalent circuit diagram of a transformer.
1.5 Regulation and Efficiency
1.5.1 Explain the various losses in a transformer.
1.5.2 Explain open circuit and short circuit test on transformer to find no load and
1.5.3 Define voltage regulation in the transformer.
1.5.4 Write equation for voltage regulation.
1.5.5 Calculate the efficiency of transformer at given loads.
1.5.6 State the condition for maximum efficiency
1.5.7 Define all day efficiency.
1.5.8 Solve the problems on the above.
1.6 3 phase transformers
1.6.1 Explain working principle and construction of 3 phase transformers.
1.6.2 Explain star-star, Delta-Delta, star-Delta, Delta-star, open delta and Scott
1.7 Cooling of transformer
1.7.1 Explain the necessity of cooling of transformer.
1.7.2 List the various types of cooling of transformer.
1.7.3 Write the meaning of AN, ON, OFA.
1.8 Welding transformer
1.8.1 Explain the construction and write the applications of a welding transformer.
1.9 Auto transformer
1.9.1 Explain briefly an auto transformer.
1.9.2 Compare auto transformer with two winding transformer.
1.9.3 List the application of auto transformer.
1.10 Parallel operation
1.10.1 Explain the necessity and conditions for parallel operation.
1.10.2 Explain with neat sketches parallel operation of single phase
transformers with their load sharing.
2 Induction motor
2.1 Working principle
2.1.1 Explain the working principle of induction motor.
2.1.2 Compare with it a transformer.
2.1.3 Explain how the rotating magnetic field is produced by poly phase supply.
2.1.4 Define the terms slip, frequency of rotor current.
2.2.1 Describe the construction of stator, squirrel cage rotor and phase wound rotor.
2.3.2 Derive an expression for starting torque.
2.3.3 Compare the starting torques of squirrel cage and slip ring induction motor.
2.3.4 State the condition for max starting torque.
2.3.5 Explain the effect of change in supply voltage on starting torque.
2.3.6 State equation for torque under running conditions.
2.3.7 Draw torque - slip curves.
2.3.8 State relationship between
1. Full load torque and maximum torque.
2. Starting torque and maximum torque.
2.4 Equivalent circuit
2.4.1 Draw the equivalent circuit of an induction motor.
2.5 Power output
2.5.1 State the relationship between rotor power input, rotor copper loss, and mechanical
power developed and slip.
2.5.2 Solve problems on the above.
2.6 Circle diagrams
2.6.1 Construct the circle diagram for the given 3 induction motor using the no-load and
blocked rotor test results.
2.6.2 Calculate slip rotor stator copper losses, power factor, efficiency, speed regulation for
Full load conditions from above circle diagram.
2.6.3 Solve problems on the above.
2.7.1 Explain the necessity of starters for 3 induction motors and list the various types of
2.7.2 Explain the construction and working of
1. D.O.L. Starter 2. Soft Starter 3. Star-Delta Starter
2.8 Speed control
2.8.1 With neat circuit diagram. Explain the speed control of 3 induction motor.
1. Change of applied voltage
2. Change of frequency(Variable voltage and variable frequency)
3. Change of poles
4. Rheostat control.
2.8.2. Explain the principle of working & application of linear induction motor.
2.8.3 Explain Induction Generators and its applications.
3.1 Working principle
3.1.1 Describe the general principle of operation of synchronous motor.
3.1.2 Compare the synchronous motor with induction motor
3.2 Operation on load
3.2.1 Explain the effect of change in excitation at constant load
3.3.1 Explain the effect of excitation on armature current & power factor.
3.3.2 Define V-curves & inverted V-curves & draw the same.
3.4.1 Explain hunting and its prevention.
3.5.1 Explain the methods of starting synchronous motor.
3.6.1 Explain the applications of synchronous motors.
3.7 Permanent Magnet Synchronous motor
3.7.1 Explain permanent magnet Synchronous motor.
3.7.2 State the characteristics of permanent magnet.
3.7.3 List the properties of NEODYMIUM, SAMARIUM, COBALT, FERRITE,
4 Single phase motors
4.1 Split phase induction motor
4.1.1 State the principle of working of single phase induction motor.
4.1.2 Name different types of single phase induction motor.
4.1.3 Explain the construction, principle of operation, characteristics &applications of
a) Single phase capacitor start capacitor run I.M b) Single phase capacitor start
induction run I.M
1. Electrical Technology volume 2 – by BL Theraja & A.K.Theraja S.Chand publication
2. Principles of Electrical Machines by V.K.Mehtha.S.Chand publication
3. Electrical Machines by Bhattacharya. Tata McGraw Hill Co.
4. Electrical Machines – by J.B.Guptha Kataria & Sons Publications.
5. Generation of Electrical Energy by BR Gupta. S.Chand Publication.
6. Fundamentals of elecrical drives – by G.K. Dubey Narosa publications.
7. Electrical Machines – by Deshpande.