Single and Three Phase Wattmeter and Energy Meters

8/18/2019 Single and Three Phase Wattmeter and Energy Meters

1/29

Electrical And Electronics

Instruments

N Krishna Prakash


2/29

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 attmeter

Single and three phase energy meters!

Magnetic measurements

"etermination of #-$ curveMeasurements of iron loss

Instrument transformers

Instruments for measurement of fre%uency and

phase


3/29

&nalog Instruments &n analog device is one in hich the

output or display is a continuousfunction of time and 'ears aconstant relation to its input!


4/29

(lassi)cation

(lassi)ed 'ased upon the %uantity theymeasure *ammeter+ voltmeter,

(lassi)ed according to the current thatcan 'e measured 'y them!*"(+&(,

(lassi)ed according to the eects usedfor orking!

(lassi)ed as Indicating+ .ecording+Integrating! (lassi)ed on the 'asis of method used

for comparing the unknon %uantity!

*"irect / (omparison measurement ,


5/29

Principle of operation Magnetic 0ect!

Thermal 0ect!

0lectrostatic 0ect

Induction 0ect!

$all 0ect!


6/29

Magnetic 0ect


7/29


8/29

1orce #eteen (urrent

carrying Magnet


9/29

1orce #eteen To (urrent

(arrying (oils


10/29

$all 0ects


11/29

perating 1orces "e3ecting 1orce!

(ontrolling 1orce!

"amping 1orce!


12/29

Supporting the moving

element Suspension

Taut Suspension

Pivot and 4eel 'earings!


13/29

(ontrol Systems 5ravity (ontrol!

Spring (ontrol!


14/29

&nalog &mmeters &mmeters are connected in series

in the circuit hose current is to 'emeasured! The poer loss in anammeter is I2.a!Therefore ammeters

should have a lo electrical

resistance so that they cause asmall voltage drop andconse%uently a'sor' small poer!


15/29

&nalog 6oltmeters 6oltmeters are connected in parallel

in the circuit hose voltage is to 'emeasured! The poer loss in anammeter is 62/.6!Therefore

voltmeters should have a high

electrical resistance so that theycause a small voltage drop andconse%uently a'sor' small poer!


16/29

Types of Instruments

Permanent magnet moving coil*PMM(,!

Moving Iron 0lectro-dynamometer type! $ot ire type!

Thermocouple type! Induction type! 0lectrostatic type!

.ecti)er type!


17/29

PMMC


18/29

Moving Iron Instruments&ttraction Type


19/29

.epulsion Type Moving IronInstruments


20/29

0lectrodynamometer Type


21/29

7attmeter


22/29

Poer Measurement in 8phase 8 ire system


23/29

To attmeter method


24/29


25/29


26/29

0nergy meters


27/29

Single Phase 0nergy Meter


28/29

Poly Phase 0nergy Meter


29/29

T$&NK 9U

Single and Three Phase Wattmeter and Energy Meters

Documents