ELECTRIC MOTORS AND TRANSFORMERS

ELECTRIC MOTORS AND TRANSFORMERS (ELECTRICAL ENGINEERING GROUP) 

 Course Objectives: 

The aim of this course is to help the student to attain the following industry identified competency through various teaching learning experiences: 

• Provide the basic concept of DC machines and Transformers. 
• Develop the skills of the students in the areas of machines and transformers by identifying the current problem in the industries and bring solutions through research. 
• Diagnose the condition of DC machines and Transformers. 
• Maintain electric motors and transformers.

Course Outcomes:

The theory, practical experiences and relevant soft skills associated with this course are to be taught and implemented, so that the student demonstrates the following industry-oriented Co associated with the above-mentioned competency: 

a) Maintain different types of DC generators 

b) Maintain different types of DC motors.

c) Maintain single phase transformer. 

d) Maintain three phase transformers. 

e) Maintain different types of special purpose transformers used in different applications. 

 THEORY-2020304, L-4, TA-10, CT-20, ESE-70, Total-100. Credit-4.

Unit -I   DC Generators (12 Hours)

• DC generator: construction, parts, materials and their functions.
• Principle of operation of DC generator: Fleming’s right-hand rule, schematic diagrams
• E.M.F. equation of generator,
• Armature reaction, commutation.
• Applications of DC generators.

Unit - II   D.C. Motors (14 Hours)

• DC motor: Types of DC motors. 
• Fleming’s left-hand rule, Principle of operation of, 
• Back E.M.F and its significance, 
• Voltage equation of DC motor. 
• Torque and Speed; Armature torque, Shaft torque, BHP, Brake test, losses, efficiency. 
• DC motor starters: Necessity, two point and three-point starters. 
• Speed control of DC shunt and series motor: Flux and Armature control. 
• Brushless DC Motor: Construction and working.

Unit -III    Single Phase Transformers (14 Hours)

• Types of transformers: Shell type and core type; 
• Construction: Parts and functions, 
• materials used for different parts: CRGO, CRNGO, HRGO, amorphous cores, 
• Transformer: Principle of operation, 
• EMF equation of transformer: Derivation, Voltage transformation ratio, 
• Significance of transformer ratings 
• Transformer No-load and on-load phasor diagram, Leakage reactance, 
• Equivalent circuit of transformer: Equivalent resistance and reactance. 
• Voltage regulation and Efficiency: Direct loading OC/SC method, All day efficiency.

Unit -IV   Three Phase Transformers (16 Hours)

• Bank of three single phase transformers, Single unit of three phase transformer 
• Distribution and Power transformers. Construction, cooling, 
• three phase transformers connections as per IS:2026 (part IV)- 1977, 
• Three phase to two phase conversion (Scott Connection), 
• Selection of transformer as per IS: 10028 (Part I)-1985, 
• Criteria for selection of distribution transformer, and power transformer, Amorphous Core type Distribution Transformer, Specifications of three- phase distribution transformers as per IS:1180 (part I)-1989 
• Need of parallel operation of three phase transformer, Conditions for parallel operation. 
• Polarity tests on mutually inductive coils and single-phase transformers; Polarity test, Phasing out test on Three-phase transformer.

Unit -V Special Purpose Transformers (08 Hours)

• Single phase and three phase auto transformers: Construction, working and applications. 
• Instrument Transformers: Construction, working and applications of Current transformer and Potential transformer. 
• Isolation transformer: Constructional Features and applications. 
• Single phase welding transformer: constructional features and applications. 
• Pulse transformer: constructional features and applications. 
• ‘K’ factor of transformers: overheating due to non-linear loads and harmonics.

ELECTRIC MOTORS AND TRANSFORMERS LABORATORY -2020310 (P-2, PA-15, ESE-35, C-1)

Practical’s:

1. Dismantle a DC machine.

2. Reverse the direction of rotation of the DC shunt motor. 

3. Perform brake test on DC shunt motor. 

4. Control the speed of DC shunt motor by different methods. 

5. Control the speed of DC series motor by different methods. 

6. Perform the brake test on DC series motor. 

7. Check the functioning of single-phase transformer. 

8. Determine regulation and efficiency of single-phase transformer by direct loading. 

9. Perform open circuit and short circuit test on single phase transformer to determine equivalent circuit constants, voltage regulation and efficiency. 

10. Perform parallel operation of two single phase transformers to determine the load current sharing.

11. Perform parallel operation of two single phase transformers and determine the apparent and real power load sharing. 

12. Perform polarity test on a single-phase transformer whose polarity markings are masked. 

13. Perform phasing out test on a three-phase transformer whose phase markings are masked. 

14. Connect the auto-transformer in step-up and step-down modes noting the input/output readings. 

15. Check the functioning of the CT, PT and isolation transformer. 

16. Test the pulse transformer. 

References: 

1. Electrical Machines, Vol- I, II by G.C. Garg & P.S. Bimbhra, Khanna Book Publishing House (ISBN:978- 9386173-447, 978-93-86173-607), New Delhi 

2. Mittle, V.N.and Mittle, Arvind., Basic Electrical Engineering, McGraw Hill Education,New Delhi, ISBN: 9780070593572 

3. Electrical Machines by D.P Kothari .and Nagrath, I.J.Mc Graw Hill Education. New Delhi, ISBN: 9780070699670 

4. Electrical Machines by J.B. Gupta Mc Graw Hill Education, New Delhi, ISBN:9789332902855 

5. Principle so Electrical Machines by Rohit Mehta, and V.K.Mehta, S.Chand and Co.Ltd.,New Delhi, ISBN: 9788121930888 

6. Electrical Technology Vol-II (A C and DC machines) by B.L. Theraja, S.Chand and Co. Ltd., New Delhi, ISBN: 9788121924375 

7. Electrical Machines Theory and Practice, M.N.Bandyopadhyay, PHI Learning Pvt.Ltd., New Delhi, ISBN: 9788120329973Vi 

8. DC Machines and Transformers by K.Murugesh Kumar, ISBN:9788125916055 

9. Electric Motors and Transformers Deepak Kumar FPH

Concept map:

SBTE syllabus- EE & EEE- 3rd Semester  

Syllabus (bihar.gov.in)