MEASURING INSTRUMENTS and measurement PPT.pptx

Eim

1. Unit-4 Measuring Instruments Mr. K. Shankar Assistant Professor EEE Dept. LIET

2. Syllabus of Unit-4 Classification of Measuring Instruments Deflection, controlling, damping torque Ammeter, voltmeter, wattmeter, MI, MC instruments Working of Energy meter Construction of CRO.

3. Measuring Instruments are mainly two types Absolute Instruments : which measures quantity to be measured in terms of physical parameters. Galvanometer Secondary Instruments : which measures electrical quantity such as voltage, current, power.

4. Secondary Instruments Indicating Instruments: which measure the magnitude of electrical quantity at the time of measuring. Ex: ordinary ammeter & voltmeter those are used in labs Integrating Instruments: which measure total electricity (or) total energy over a period of time. Ex: Energy meter Recording Instruments: which measure continuously variation of electrical quantities for specific period of time. Ex: Record ammeter & Record voltmeter mostly used in generating stations

5. Construction of Moving Coil Instrument

6. Torques Different types of torques are required in an instrument, those are: Deflecting (or operating) torque. Controlling (or restoring) torque. Damping torque.

7. Types of Torques Deflecting torque Controlling torque: Spring Control Gravity Control Damping torque: Air Friction Damping Torque Fluid Friction Damping Torque Eddy Current Damping Torque

8. Spring Control Torque Controlling Torque

9. Gravity Control Torque Controlling Torque

10. Damping Torque Air Friction Damping Torque

11. Damping Torque Fluid Friction Damping Torque

12. Damping Torque Eddy Current Damping Torque

13. Moving Coil Instrument

14. Moving iron Instrument There are Two types of Moving Iron Instruments: Attraction type Moving iron instrument Repulsion type Moving iron instrument

15. Attraction type Moving iron Instrument

16. Repulsion type Moving iron Instrument Front View Top View

17. Wattmeter

18. Energy meter Driving System Moving System Braking System Registering System

19. Cathode Ray Oscilloscope (CRO) Cathode Ray Tube Electronic Gun Assembly Deflecting Plate Fluorescent Screen For CRT Which measures the signal in the form of voltage.

20. Cathode Ray Oscilloscope (CRO) Cathode Ray Tube

21. Cathode Ray Oscilloscope (CRO) Deflecting Plate

22. Cathode Ray Oscilloscope (CRO) Electronic Gun Assembly

23. Cathode Ray Oscilloscope (CRO) Fluorescent Screen For CRT

24. Syllabus of Unit-4 Classification of Measuring Instruments Deflection, controlling, damping torque Ammeter, voltmeter, wattmeter, MI, MC instruments Working of Energy meter Construction of CRO.

25. Thank you