Transcript Electrical And Electronics Instruments

Electrical And Electronics
Instruments
N Krishna Prakash
04-03-09
Nkp/eee skcet
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
04-03-09
Nkp/eee skcet
2
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.
04-03-09
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
)
04-03-09
Nkp/eee skcet

Principle of operation





Magnetic Effect.
Thermal Effect.
Electrostatic Effect
Induction Effect.
Hall Effect.
04-03-09
Nkp/eee skcet
Magnetic Effect
04-03-09
Nkp/eee skcet
04-03-09
Nkp/eee skcet
Force Between Current carrying
Magnet
04-03-09
Nkp/eee skcet
Force Between Two Current
Carrying Coils
04-03-09
Nkp/eee skcet
Hall Effects
04-03-09
Nkp/eee skcet
Operating Forces



Deflecting Force.
Controlling Force.
Damping Force.
04-03-09
Nkp/eee skcet
Supporting the moving
element



Suspension
Taut Suspension
Pivot and jewel bearings.
04-03-09
Nkp/eee skcet
Control Systems


Gravity Control.
Spring Control.
04-03-09
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 I2Ra.Therefore ammeters
should have a low electrical
resistance so that they cause a small
voltage drop and consequently
absorb small power.
04-03-09
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 V2/RV.Therefore
voltmeters should have a high
electrical resistance so that they
cause a small voltage drop and
consequently absorb small power.
04-03-09
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.
 04-03-09
Rectifier type.
Nkp/eee skcet

PMMC
04-03-09
Nkp/eee skcet
Moving Iron Instruments
Attraction Type
04-03-09
Nkp/eee skcet
Repulsion Type Moving Iron
Instruments
04-03-09
Nkp/eee skcet
Electrodynamometer Type
04-03-09
Nkp/eee skcet
Wattmeter
04-03-09
Nkp/eee skcet
Power Measurement in 3 phase 3
wire system
04-03-09
Nkp/eee skcet
Two wattmeter method
04-03-09
Nkp/eee skcet
04-03-09
Nkp/eee skcet
04-03-09
Nkp/eee skcet
Energy meters
04-03-09
Nkp/eee skcet
Single Phase Energy Meter
04-03-09
Nkp/eee skcet
Poly Phase Energy Meter
04-03-09
Nkp/eee skcet
THANK YOU
04-03-09
Nkp/eee skcet