23042-MEASUREMENTS AND INSTRUMENTS IMPORTANT QUESTIONS

KUMARAN POLYTECHNIC COLLEGE

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

23042-MEASUREMENTS AND INSTRUMENTS

STAFF-IN-CHARGE: N.SURESH KUMAR

IMPORTANT QUESTIONS

UNIT-I

PART-A

1.      What is the formula for error?

2.      Based on limit of error, how the instruments are classified?

3.      What is the jewel that is used for bearing in instruments?

4.      State a formula for correction.

5.      Define true value.

6.      Write the formula for instrument efficiency.

7.      List the three operating forces.

8.      Mention the functions of measurement systems.

9.      Define Accuracy.

10. What are the two essential requirements of moving systems?

11.  Define error.

12. Define Instrument efficiency.

13. List the types of supports.

PART-B

1.      Mention the various operating forces of measuring instruments.(12)

2.      Explain with neat sketches the various types of supports used in indicating instruments.(12)

3.      Explain with neat sketch any two types of supports used in indicating instruments.(6)

4.      Explain eddy current damping in instrument with neat sketch. (6)

5.      Write short notes on: (a) Permanent magnets. (4) (b) Pointers (4) (c) Scales in indicating instruments.(4)

6.      Explain spring control used in Instruments. (6)

7.      Explain Eddy current damping in Instruments with neat sketches. (6)

8.      List various effects used in Instruments explain any one. (6)

9.      Explain Air friction damping and Fluid friction damping (12)

10. Explain spring control and gravity control (12)

UNIT-II

PART-A

1.      What is the relation between Ө and I in an attraction type MI?

2.      PMMC meter have uniform scales. Why?

3.      List the two types of instruments transformers.

4.      What are the two types of MC instruments?

5.      Expand CT and PT.

6.      Where are shunts used?

7.      State use of tong tester.

8.      Which type of instruments is used for AC measurements?

9.      What are the two types of MI instruments?

10. Write the formula to find shunt resistance.

11. State the uses of multi meter.

12. State the use of shunts.

13. Write the formula to find multiplier resistance.

14. Name the instrument used for measuring high resistance.

15. What are the errors in CT and PT?

PART-B

1.      Explain the construction and working of megger with neat sketch. (12)

2.      Explain with a neat sketch the working of an attraction type moving iron meter.(12)

3.      Explain with neat sketch the construction and working of permanent magnet moving coil instrument. Derive torque equation. (12)

4.      With neat sketch explain the construction and working of Earth tester.(12)

5.      Explain with neat sketch, construction and working of dynamometer type moving coil meter.(12)

6.      Explain with a neat sketch the working of repulsion type moving iron meter.(12)

7.      Explain with a neat sketch the working of shaded pole induction instrument.(12)

8.      Explain about CT and PT. (12)

9.      Explain Kelvin bridge and Wheatstone bridge. (12)

UNIT-III

PART-A

1.      State the formula for power in 1 –m AC circuits.

2.      In dynamometer wattmeter, which coil is found to be current coil?

3.      State the use of energy meter.

4.      State the use of power factor meter.

5.      Name the two coils in wattmeter.

6.      What is RSS meter?

7.      What is meant by creep?

8.      Write any two types of wattmeter.

9.      Differentiate power and energy.

10. Write the formula to find power in DC circuit and A.C circuit.

11. How creep is overcome in energy meter?

12. State the unit of power and energy.

13. List the four Mechanism in AC energy meter?

14. What is the purpose of lagplate in energy meter?

PART-B

1.      Explain the construction and working of three phase wattmeter with neat sketch. (12)

2.      What are errors and the adjustment procedures in energy meters? (6)

3.      Draw and explain the block diagram of digital energy meter. (12)

4.      Explain with a neat sketch, the construction and operation of three phase Energy meter. (12)

5.      Draw and explain the construction and operation of Electro dynamometer type Wattmeter. (12)

6.       Draw and explain the block diagram of Digital energy meter. (12)

7.      With neat circuit explain the operation of single phase energy meter.(12)

8.       With neat sketch explain the working of LPF wattmeter. (12)

UNIT-IV

PART-A

1.      State the use of phase sequence indicator.

2.      List the two types of synchroscope.

3.      What type of instrument is western frequency meter?

4.      List the two types of maximum demand indicator.

5.      Name the two types of power factor meters.

6.      Mention the use of synchroscope.

7.      Name any two types of frequency meters.

8.      What are the types of phase sequence indicator.

9.      What is maximum demand indicator?

10. What are the three quantities measured by trivector meter?

11. What is phase sequence indicator?

12. What are the sources of synchronization?

PART-B

1.      Explain the working of Trivector meter with neat sketch. (12)

2.      Explain the working of single-phase dynamometer power factor meter. (12)

3.      Explain the operation of western type frequency meter with a neat sketch.(12)

4.      Explain with a neat sketch the construction and working of a three phase dynamometer power factor meter. (12)

5.      With neat sketch explain the construction and operation of power factor meter.(12)

6.      Explain the working of Merz Price MDI with neat diagram. ( 12)

7.      Explain the operation of Weston type frequency meter with neat diagram.(12)

8.      Draw the block diagram of Digital frequency meter and explain.(12)

UNIT-V

PART-A

1.      What is the use of Anderson bridge?

2.      Mention any two controls of CRO?

3.      Mention two parts of CRT.

4.      Mention any two modes of Dual trace oscilloscope.

5.      Write the coating material on CRT screen.

6.      Name the bridge used for measurement of capacitance.

7.      All arms of schering bridge is provided with metallic screen. Why?

8.      What is the main use of digital storage oscilloscope?

9.      Name the bridge used for measurement of inductance.

10. What is time base as referred to CRO?

11. Name the fluorescent materials used in CRO screen.

12. List any two applications of CRO.

13. State the difference between Dual trace CRO and ordinary CRO.

PART-B

1.      Explain Schering bridge method to find unknown capacitance in a       circuit.(6)

2.      State the applications of digital storage oscilloscope. (6)

3.      Draw and explain the block diagram of general purpose CRO. (12)

4.      With a neat sketch explain the constructional features of a cathode ray tube (CRT).(6)

5.      Draw the circuit diagram of an Anderson Bridge and explain how the unknown induction is found.(6)

6.      Draw and explain the block diagram of digital storage oscilloscope                                         and explain. (6)

7.      Draw the block diagram of CRO and explain. (6)

8.      Draw the block diagram of Dual trace CRO and explain. (6)