Nkp/eee skcet Electrical And Electronics Instruments N Krishna Prakash

Nkp/eee skcet 2 UNIT - 2 ELECTRICAL AND ELECTRONICS INSTRUMENTS Principle and types of analog voltmeters Principle and types of digital voltmeters Principle and types of Multimeter Single and three phase wattmeter Single and three phase energy meters. Magnetic measurements Determination of B-H curve Measurements of iron loss Instrument transformers Instruments for measurement of frequency and phase

Nkp/eee skcet Analog Instruments An analog device is one in which the output or display is a continuous function of time and bears a constant relation to its input.

Nkp/eee skcet Classification Classified based upon the quantity they measure (ammeter, voltmeter) Classified according to the current that can be measured by them.(DC,AC) Classified according to the effects used for working. Classified as Indicating, Recording, Integrating. Classified on the basis of method used for comparing the unknown quantity. (Direct / Comparison measurement )

Nkp/eee skcet Principle of operation Magnetic Effect. Thermal Effect. Electrostatic Effect Induction Effect. Hall Effect.

Nkp/eee skcet Magnetic Effect

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Nkp/eee skcet Force Between Current carrying Magnet

Nkp/eee skcet Force Between Two Current Carrying Coils

Nkp/eee skcet Hall Effects

Nkp/eee skcet Operating Forces Deflecting Force. Controlling Force. Damping Force.

Nkp/eee skcet Supporting the moving element Suspension Taut Suspension Pivot and jewel bearings.

Nkp/eee skcet Control Systems Gravity Control. Spring Control.

Nkp/eee skcet Analog Ammeters Ammeters are connected in series in the circuit whose current is to be measured. The power loss in an ammeter is I 2 R a.Therefore ammeters should have a low electrical resistance so that they cause a small voltage drop and consequently absorb small power.

Nkp/eee skcet Analog Voltmeters Voltmeters are connected in parallel in the circuit whose voltage is to be measured. The power loss in an ammeter is V 2/ R V.Therefore voltmeters should have a high electrical resistance so that they cause a small voltage drop and consequently absorb small power.

Nkp/eee skcet Types of Instruments Permanent magnet moving coil (PMMC). Moving Iron Electro-dynamometer type. Hot wire type. Thermocouple type. Induction type. Electrostatic type. Rectifier type.

Nkp/eee skcet PMMC

Nkp/eee skcet Moving Iron Instruments Attraction Type

Nkp/eee skcet Repulsion Type Moving Iron Instruments

Nkp/eee skcet Electrodynamometer Type

Nkp/eee skcet Wattmeter

Nkp/eee skcet Power Measurement in 3 phase 3 wire system

Nkp/eee skcet Two wattmeter method

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Nkp/eee skcet Energy meters

Nkp/eee skcet Single Phase Energy Meter

Nkp/eee skcet Poly Phase Energy Meter

Nkp/eee skcet THANK YOU