Download EXP:01 - NPKauto

EXPT.NO.1
TITLE:
TO MEASURE VOLTAGE ,CURRENT AND POWER IN A SINGLE PHASE A.C.SUPPLY.
APPARATUS:



A.C.VOLTMETER
A.C.AMMETER
AC WATTMETER
RESITIVE OR LAMP
LOAD
0 TO 300 VOLT.
0 TO 5 AMP.
0 TO 5 AMP , 0 TO 300/600 VOLTS
PRIOR CONCEPTS:



VOLTAGE IS POTENTIAL DIFFERECE BETWEEEN TWO POINTS.
CURRENT IS CONVENTIAL FLOW OF ELETRON.
POWER IS SIM PLY PRODUCT OF VOLTAGE ,CURRENT & POWER FACTOR.
POWER FACTOR OF LAMP LOAD OR SIMPLE RESITIVE LOAD IS UNITY.
NEW CONCEPTS:
PROPSITION 1:

INDUCED E.M.F. IS AS PER FARADAY`S LAW OF ELECTROMANGENTIC INDUCTION.

POWER IS DEFINED AS RATE OF DOING WORK.

UNIT OF POWER IS WATT(LARGER UNITS ARE KILOW,MEGAWATT)
CONCEPT STRUCTURE 1 :MEASUREMENT OF VOLTAGE ,CURRENT & POWER
VOLTAGE IS POTENTIAL
DIFFERECE BETWEEEN
TWO POINTS &
MEASURES WITH THE
HELP OF VOLTMETER OR
MULTIMETER.
CURRENT IS
CONVENTIAL FLOW OF
ELETRON & IS
MEASURED WITH THE
HELP OF AMMETER.
POWER IN A.C. CIRCUIT IS
MEASURED WITH
WATTMETER WHICH WILL
ACCOUNT FOR POWER
FACTOR.
ALL THESE METERS USES CURRENT OR SMALL FRACTION OF CURRENT TO MEASURE
QUANTITY UNDER MEASUREMNT.
PROPSITION 2:
 AS ELECTRICAL SUPPLIES ARE OF TWO TYPE METER ARE ALSO OF TWO TYPES .
 SOME METERS ARE ONLY USED ON D.C. SUPPLY AND SOME TYPES OF METER ARE
USED ON BOTH ON A.C. AS WELL AS D.C.
CONCEPT STRUCTURE 2 :TYPES OF METERS
USED ON D.C.SUPPLY
P.M.M.C. METERS ARE USED
USED ON A.C.SUPPLY
M.I.TYPE METER ARE USED
PROPSITION 3 :
ENERGY IS DIVIDED THE CAPACITY OF DOING .

ENERGY MULTIFICATION OF POWER AND TIME.

UNIT OF ENERGY IS JOULES ALSO KNOWN AS WATT SECOND DENOTED BY KWH,MWH
 CONCEPT STRUCTURE 3:ENERGY IS PRODUCT OF POWER AND TIME FOR WHICH IS CONSUMED
POWER IS MEASURED WITH
THE WATTMETER.
TIME FOR SOME PARTICULAR REVOLUTION
CAN BE MEASURED STOPWATCH.
PRODUCT OF THESE TWO QUANTITIES GIVES
MEASURE OF ENERGY.
LEARNING OBJECTIVES:INTELLECTUAL SKILLS:
TO UNDERSTAND THE CONCEPT OF MEASUREMENT OF POWER IN SINGLE PHASE
CIRCUITS.

TO UNDERSTAND THE CONCEPT OF MEASUREMENT OF ENERGY CONSUMED IN
SINGLE PHASE CIRCUITS.

TO UNDERSTAND THE CONCEPT OF POWER FACTOR OF RESISTIVE CIRCUITS LIKE
LAMP LOADS.
MOTOR SKILLS:

ABILITY TO CONNECT AMMETER IN SERIES WITH THE CIRCUIT THROUGH WHICH
CURRENT IS TO BE MEASURED.

ABILITY TO CONNECT VOLTMETER ACROSS WHICH VOLTAGE IS TO BE MEASURED.

ABILITY TO CONNECT CURRENT COIL & PRESSURE COIL OF WATTMETER IN A WHICH
POWER IS TO BE MEASURED.
INSTRUMENT:
SR.NO. INSTRUMENT
1.
WATTMETER
2.
AMMETER
3.
VOLTMETER
NAME OF
MANUFACTURER
SERIAL NO.OF THE
INSTRUMENT
STEPWISE PROCEDURE:

CONNECT THE CIRCUIT AS SHOWN IN THE FIG.

VARY THE RESISTIVE LOAD OR LAMP LOAD STEP BY STEP.

RECORD THE VALUES OF VOLTAGE ,CURRENT,POWER & TIME REQUIRED FOR SAME
FIXED NUMBER OF REVOLUTIONS OF ENERGY METERS DISCS

NOPTE DOWN SUCH 4 TO 5 READINGS.

GRADUALLY DECREASE THE LAMP LOAD.

WHEN LOAD IS ZERO SWITCH OFF THE SUPPLY.
OBSERVATIONS:
SR.NO.
VOLTAGE (V)
(Volt)
CURRENT
(I)
MEASURED POWER
(Watt)
(Amp.)
1.
2.
3.
4.
5.
6.
7.
CALCULATIONS:

POWER = VOLTAGE x CURRENT
RESULT:

VOLTAGE CAN BE MEASURED WITH HELP OF --------.

CURRENT CAN BE MEASURED WITH HELP -------------.

WATTMETER MEASURED ----------- IN THE CIRCUIT.
CALCULATED POWER
(Watt) =V x I
QUESTIONS:
Q1.DEFINE POWER WITH IT`S UNIT?
Q2.WHAT IS POWER FACTOR? WHAT IS IT`S IMPORTANCE IN TARRIF?
CIRCUIT DIAGRAM