INDUSTRIETECHNIK
SRI LANKA INSTITUTE of ADVANCED TECHNOLOGICAL EDUCATION
ELECTRICAL and ELECTRONIC ENGINEERING Instructor Manual
Training Unit
Electric lectr ica al Me Measuri su ring ng Techni ch niqu que es 2 Practice
No: EE 076
Training Unit Electr Electrical ical Measuring sur ing Techniqu chn ique es 2 Practical Part
No.: EE 076
Edition:
2008 Al l Righ Ri gh ts Reserved Reser ved
Editor:
MCE MCE Industrietechnik Linz GmbH & Co Education and Training Systems, DM-1 Lun zerstrass e 64 P.O.Box P.O.Box 36, A 4031 Lin z / Aust ria Tel. (+ 43 / 732) 6987 – 3475 Fax (+ 43 / 732) 6980 – 4271 Website: Website: www.mcelinz.com
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ELECTRICAL MEASURING TECHNIQUES 2
CONTENTS
Learning objectives
Page
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PRACTICAL EXERCISE 1 Current measurement
PRACTICAL EXERCISE 2 Voltage measurement
PRACTICAL EXERCISE 3 Current and voltage measurement
PRACTICAL EXERCISE 4 Current and voltage measurement
PRACTICAL EXERCISE 5 Current and voltage measurement
2
ELECTRICAL MEASURING TECHNIQUES 2 LEARNING OBJECTIVES
The trainee should …
… be able to measure current. … be able to measure voltage. … be able to measure current and voltage for resistances in series. … be able to measure partial and total current for resistances in parallel. … be able to measure current and voltage for resistances in mixed (series and parallel) circuits.
3
ELECTRICAL MEASURING TECHNIQUES 2
PRACTICAL EXERCISE 1 Current measurement
1. TASK
Measurement of current in a given circuit.
2. EQUIPMENT
R1 = variable resistor 196 Ω/250 W P1 = ammeter ohmmeter
3. CARRY OUT THE EXERCISE
- adjust the variable resistor to 10 Ohm with use of the ohmmeter - connect up the circuit
4
-
measure the current
-
record the result in the measurement report
Ammeters are always connected connected in series with the load. load.
5
ELECTRICAL MEASURING TECHNIQUES 2
PRACTICAL EXERCISE 2 Voltage measurement
1. TASK
Measurement of current in a given circuit.
2. EQUIPMENT
R1 = variable resistor 196 Ω/250 W P1 = voltmeter
3. CARRY OUT THE EXERCISE
-
adjust the variable resistor to 10 Ohm with use of the ohmmeter
-
connect up the circuit
6
-
measure the current
-
record the result in the measurement report
Voltmeters are always connected in series with the load.
7
ELECTRICAL MEASURING TECHNIQUES 2
PRACTICAL EXERCISE 3 Current and voltage measurement
1. TASK
Current and voltage measurement for resistances in series.
2. EQUIPMENT
P1 = ammeter P2 = voltmeter P3 = voltmeter P4 = voltmeter R1 = resistance 100 ohms R2 = resistance 220 ohms
3. CARRY OUT THE EXERCISE
- connect up according to circuit diagram
8
-
measure the current and voltage
-
record the results in the measurement report
P1
P3
P4
P2
Itot [A]
Ui[V]
U2[V]
U [V]
In a series-connected circuit, the partial voltages (voltage drops) are proportional to the resistance across which they are measured. Utotal = U1 + U2 + ….
Rtotal = R1 + R2 + ….
9
ELECTRICAL MEASURING TECHNIQUES 2
PRACTICAL EXERCISE 4 Current and voltage measurement
1. TASK
Current and voltage measurement for resistances in parallel.
2. EQUIPMENT
P1 = ammeter P2 = ammeter P3 = ammeter P4 = voltmeter R1 = resistance 470 ohms R2 = resistance 100 ohms
3. CARRY OUT THE EXERCISE
- connect up according to circuit diagram
10
-
measure the current and voltage
-
record the results in the measurement report
P4
P1
P2
P3
Utotat[V]
Itotal [A]
I1[A]
I2[A]
In a parallel-connected circuit, the partial currents are inversely. proportional to the resistances.
Itotal = I1 + I2 + ….
11
ELECTRICAL MEASURING TECHNIQUES 2
PRACTICAL EXERCISE 5 Current and voltage measurement
1. TASK
Current and voltage measurement for resistances in mixed (series and parallel) circuits.
2. EQUIPMENT P1 = ammeter P2 = ammeter P3 = ammeter P4 = voltmeter R1 = resistance 470 ohms R2 = resistance 220 ohms R3 = resistance 330 ohms
3. CARRY OUT THE EXERCISE
- connect up according to circuit diagram
12
-
measure the current and voltage
-
record the results in the measurement report
P1
P4
P5
P6
P2
P3
Itotal [A]
Utotal [v]
U1 [V]
U2 [V]
I1 [A]
I2 [A]
13
EE076 Electr Electrical ical Measuring sur ing Techniqu chn ique es 2
Instructions for Practical Exercises
14
ELECTRICAL MEASURING TECHNIQUES 2
INSTRUCTION for practical exercise No. 1 Current measurement Measurement of current in a given circuit.
1. CARRY OUT THE EXERCISE
-
adjust the variable resistor to 10 Ohm with use of the ohmmeter
-
connect up the circuit
-
measure the current
-
record the result in the measurement report
15
P1 I [A]
Ammeters are always connected connected in series with the load. load.
16
ELECTRICAL MEASURING TECHNIQUES 2
INSTRUCTION for practical exercise 2 Voltage measurement Measurement of current in a given circuit.
1. CARRY OUT THE EXERCISE
-
adjust the variable resistor to 10 Ohm with use of the ohmmeter
-
connect up the circuit
-
measure the current
-
record the result in the measurement report
17
P1 U [V]
Voltmeters are always connected in parallel with the load.
18
ELECTRICAL MEASURING TECHNIQUES 2
INSTRUCTION for practical exercise 3 Current and voltage measurement Current and voltage measurement for resistances in series.
1. CARRY OUT THE EXERCISE
- Connect the circuit according to the circuit diagram
19
-
measure the current and voltage
-
record the resuits in the measurement report
P1
P3
P4
P2
Itot [A]
U1 [V]
U2[ V]
U [V]
In a series-connected circuit, the partial voltages (voltage drops) are proportional to the resistance across which they are measured.
Utotal = U1 + U2 + ….
Rtotal = R1 + R2 + ….
20
ELECTRICAL MEASURING TECHNIQUES 2
INSTRUCTION for practical exercise 4 Current and voltage measurement Current and voltage measurement for resistances in parallel.
1. CARRY OUT THE EXERCISE
-
connect up according to circuit diagram Li 220V r\-//50Hz
-
measure the current and voltage
-
record the results in the measurement report
21
P4
P1
P2
P3
U totat [V]
Itotal [A]
I1 [A]
I2[A]
In a parallel-connected parallel-connected circuit, the partial currents are inversely • proportional
to
the
resistances.
Itotal = I1 + I2 + …. 1
1
1
= Rtotal
1
+ R1
+ R2
+ R3
..
1 Rtotal
= 1
1 +
R1
22
1 +
R2
+ R3
…
ELECTRICAL MEASURING TECHNIQUES 2
INSTRUCTION for practical exercise 5 Current and voltage measurement. Current and voltage measurement for resistances in mixed (series and parallel) circuits.
1. CARRY OUT THE EXERCISE
-
connect up according to circuit diagram
-
measure the current and voltage
-
record the resuits in the measurement report
23
P1
P4
P5
P6
P3
P2
Itotal [A]
Utotal [V]
U1 [V]
U2 [V]
I1 [A]
I2 [A]
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EE 076 Electr Electrical ical Measuring sur ing Techniqu chn ique es 2
Evaluation Sheet for Practical Exercises
25
EVALUATION SHEET
Name
Control No.
Group Total
. o N t e e h S
Setting up the exercise
s t n i o p e l b i s s o P
s t n i o p l a u t c A
Carrying out measurements
s t s n t i i o n p o p e l l b i a u s t s c o A P
Entries in table
s t s n t i i o n p o p e l l b i a u s t s c o A P
s t n i o p e l b i s s o P
1
4
2
4
10
2
4
2
4
10
3
4
2
4
10
4
4
2
4
10
5
4
2
4
10
20
10
20
50
Total: lntermediate Mark :
Date :
Points:
26
s t n i o p l a u t c A
KEY TO EVALUATION
PER CENT
MARK
88 – 100
1
75 – 87
2
62 – 74
3
50 – 61
4
0 – 49
5
27
EE 076 Electr Electrical ical Measuring sur ing Techniqu chn ique es 2
PRACTICAL TEST
28
ELECTRICAL MEASURING TECHNIQUES 2 PRACTICAL TEST
Current and voltage measurement an resistors in a mixed circuit.
1. TASK
-
The currents and voltages in a series-parallel circuit are to be measured and recorded in the measuring table.
-
The voltages are to be measured using a multimeter.
-
Construct the circuit.
-
Record the values measured in the table.
-
Check the results of the measurement by calculation.
-
Calculate the total resistance of the circuit.
2. EQUIPMENT
P1 = ammeter P2 = multimeter P3 = ammeter P4 = ammeter P5 = multimeter P6 = multimeter P7 = multimeter P8 = ammeter R1 = resistor 100
Ω 5
W
R2 = resistor 200
Ω 5
W
R3 = resistor 100
Ω 5
W
R4 = resistor 2.4 k Ω 5 W R5 = resistor 2.7 k Ω 5 W R6 = resistor 200
Ω 5
W
R7 = resistor 2.4 k Ω 5 W R8 = resistor 2.7 k Ω 5 W
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3. CARRY OUT THE EXERCISE
Values to be measured
P1
P2
P3
Itot [A] U1,2[V] [I1,2[V]
Measurement Calculation
30
P4
P5
P6
I2 [A]
U3 [V]
U4 [V]
P7
P8
U5 [V] I6,78 [A]
Calculation
R1,2
=
R3,4,5
=
R6,7,8
=
Rtot
=
I1,2
=
I2
=
I3,4,5
=
I6,7,8
=
Itot
=
U3
=
U4
=
U5
=
31
ELECTRICAL MEASURING TECHNIQUES 2 PRACTICAL TEST (Solution)
Current and voltage measurement an resistors in a mixed circuit.
1. CARRY OUT THE EXERCISE
-
The currents and voltages in a series-parallel circuit are to be measured and recorded in the measuring table.
-
The voltages are to be measured using a multimeter.
-
Construct the circuit.
-
Record the values measured in the table.
-
Check the results of the measurement by calculation.
-
Calculate the total resistance of the circuit.
32
33
Values to be measured
P1
P2
P3
P4
Itot [A] U1,2 [V] I1,2 [A]
I2 [A]
0.503
0.12
P5
P6
P7
P8
U3 [V] u4 [V] U5 [V] I6,7,8 [A]
Measurement Calculatio Calculation n
24
0.36
CALCULATION
34
0.46
11.04 12.42 12.42
0.139 0.139
U3 = I3,4,5 x R3 = 0.0046 x 100 = 0.46 V U4 = I3,4,5 x R4 = 0.0046 x 2400 = 11.04 V U5 = I3,4,5 x R5 = 0.0046 x 2700 = 12,42V
35
EVALUATION SHEET FOR PRACTICAL TEST
Circuit construction Correct connection of the measuring instruments
25 25
Measuring table Understanding of the circuit
15
Exact reading from measuring instruments
10 25
Calculation Knowledge of the formulae
20
Formula conversion
10
Correct results
20 50
Total:
36
100 points
KEY TO EVALUATION
PER CENT
MARK
88 – 100
1
75 – 87
2
62 – 74
3
50 – 61
4
0 – 49
5
37
