BE3254 Electrical and Instrumentation Engineering Important Questions

BE3254 Electrical and Instrumentation Engineering

Important Questions

Unit 1

1. Obtain the phasor diagram of single phase transformer when the secondary is loaded with capacitive load.
2. A single phase transformer has 350 primary turns and 1050 secondary turns. The net cross sectional area of the core is 55 cm². If the primary winding is connected to a 400v, 50Hz single phase supply, calculate.
   (i) The maximum value of the flux density in the core.
   (ii) The voltage induced in the secondary winding.
3. Draw the construction of single-phase transformer and explain its working principle.
4. Write short notes on the following:
   (i) Phase diagram
   (ii) Voltage regulation
   (iii) Harmonics
5. Explain in detail with equivalent circuit and phasor diagram the operation of transformer.
6. Write short notes on causes and method to minimize harmonics.
7.  Explain the functioning of autotransformer.

Unit 2

1. Draw the construction of a DC generator and explain its working principle.
2. Derive the EMF equation of a DC generator.
3. With circuit model, obtain the EMF and torque equation of DC motor.
4. With circuit model and relevant timing diagram, explain the functioning of stepper motor.
5. Derive the EMF and torque equation with circuit model of DC motor.
6. Explain the characteristics of brushless DC motor.

Unit 3

1. Explain any two speed control methods of three-phase induction motor.
2. Draw the construction of an alternator and explain its working principle.
3. Explain the principle of operation of single phase induction motor with its characteristic curves,
4. Explain synchronous motor with its torque equation.
5. Explain the construction, principle and equivalent circuit of three phase induction motor.
6. Derive the torque equation of synchronous motor

Unit 4

1. Compare moving coil and moving iron meters in terms of construction, working principle and applications.
2. Draw the block diagram of Digital Storage Oscilloscope and explain the functions of each block.
3.  Explain in detail with block diagram, the function performed by every element of an instrument.
4. Discuss the method to measure three phase power.
5. Describe the digital storage oscilloscope with its internal diagram.
6. Sketch the schematic diagram with the functional elements of an instrument. Explain the function performed by each of the element.
7.  Describe the operation and working principle of energy meter with its internal components.

Unit 5

1. Explain any one Earthing scheme.
2. Give an overview for power system structure.
3. Explain how a fuse rating is selected.
4. Discuss earth leakage circuit breaker.
5. Explain the generation, transmission and distribution of electrical power system
6. Explain the working principle of any two circuit breakers used in electrical power system application.
7. Give an overview on power system structure with generation, transmission and distribution components.
8. Discuss any one Earthing method.
9. Give an overview on protective devices with short note on each type.