basic electrical manual 18 scheme

Basic Electrical Engineering Laboratory,18EEL17/27
Department of Electrical & Electronics ,S.T.J.I.T.Rnr ,SRM AP Page 1
Basic Electrical Engineering Laboratory, 18ELEL17/18ELEL27
[As per Choice Based Credit System (CBCS) scheme]
SEMESTER – I/II
NAME OF STUDENT
ROLL NO:
SECTION
BATCH NO :
Staff in charge
DEPARTMENT OF ELECTRICAL AND ELECTRONICS
S.T.J.INSITITUTE OF TECHNOLOGY RANEBENNUR -581115
Prepared by Prof. SANTHOSH RAIKAR M
More suggestion and feedback mail @: acadamiceeestjit@gmail.com

Safety Precautions
1. SAFETY is of paramount importance in the Electrical Engineering Laboratories.
2. Electricity NEVER EXCUSES careless persons. So, exercise enough care and attention in
handling electrical equipment and follow safety practices in the laboratory. (Electricity is a good
servant but a bad master).
3. Avoid direct contact with any voltage source and power line voltage. (Otherwise and such
contact may subject you to electrical shock).
4. Wear rubber-soled shoes. (To insulate you from earth so that even if you accidentally contact a
live point, current will not flow through your body to earth and hence you will be protected from
electrical shock)
5. Wear laboratory-coat and avoid loose clothing. (Loose clothing may get caught on an
equipment/instrument and this may lead to an accident particularly if the equipment happens to
be a rotating machine)
6. Girl students should have their hair tucked under their coat or have it in a knot.
7. Do not wear any metallic rings, bangles, bracelets, wristwatches and neck chains. (When you
move your hand/body, such conducting items may create a short circuit or may touch a live point
and thereby subject you to electrical shock).
8. Be certain that your hands are dry and that you are not standing on wet floor. (Wet parts of the
body reduce the contact resistance thereby increasing the severity of the shock).
9. Ensure that the power is OFF before you start connecting up the circuit. (Otherwise you will
be touching the live parts in the circuit)
10. Get you circuit diagram approved by the staff member and connect up the circuit strictly as
per the approved circuit diagram.
11. Check power chords for any sign of damage and be certain the chords use safety plugs and
do not defeat the safety future of these plugs by using ungrounded plugs.
12. When using connection leads, check for any insulation damage in the leads and avoid such
defective leads.
13. Do not defeat any Safety devices such as fuse or circuit breaker by shorting across it. Safety
devices protect YOU and your equipment
14. Switch on the power to your circuit and equipment only after getting them checked up and
approved by the staff member.

15. Take the measurement with one hand in you pocket. (To avoid shock in case you accidentally
touch two points at different potentials with your two hands)
16. Do not make any change in the connection without the approval of the staff member.
17. In case you notice any abnormal condition in your circuit (like insulation heating up, resistor
heating up etc.). Switch off the power to your circuit immediately and inform the staff member.
18. Keep hot soldering iron in the holder when not in use.
19. After completing the experiment show your readings to the staff member and switch off the
power to your circuit after getting approval from the staff member.
Electrical Symbols
Single-pole Single-throw
(SPST) Switch Single Pole Double-throw (SPDT) Switch
Double-pole, Single Throw (DPST) Switch
Fuse

List of experiments:
1. Verification of KVL and KCL for DC circuits. -04
2. Measurement of current, power and power factor of incandescent lamp, fluorescent lamp, and
CFL and LED lamp. -06
3. Impedance calculation and verification for R-L and R-C circuits- using decade boxes.-09
4. Load test on a single phase transformer.-12
5. Voltage and Current relationships of three phase star/delta circuits.-14
6. Measurement of three phase power using two wattmeter method.-16
7. Speed load characteristic of a 3 phase induction motor.-18
8. Two way and three way Control of lamp and formation of truth table.-20
Demonstration Experiments (for CIE only):
1. Demonstration of fuse, MCB by creating a fault.-21-22
2. Demonstration of cut-out sections of electrical machines (DC machines, Induction machines
and synchronous machines)
Laboratory Outcomes
 Get an exposure to common electrical components.
 Make electrical connections by wires of appropriate ratings.
 Understand the usage of common electrical measuring instruments.
 Understand the basic functioning of electrical machines.

Experiment no 1 : Verification of KVL and KCL for DC circuits.
Aim: Determination of Voltage and Current in DC Circuit
Apparatus required
Slno Apparatus Specification Quantity
1 RPS unit 0-24/30V 1
2 PMMC ammeter 0-2/5A 3
3 Rheostat 100 ohm 2A 3
4 Connecting wires - -
Theory :
Statement:
KCL: The algebraic sum of the currents meeting at a node is equal to zero.
KVL: In any closed path / mesh, the algebraic sum of all the voltages is zero.
Precautions:
1. Voltage control knob should be kept at minimum position.
2. Current control knob of RPS should be kept at maximum position.
Procedure for KCL:
1. Give the connections as per the circuit diagram.
2. Set a particular value in RPS.
3. Note down the corresponding ammeter reading
4. Repeat the same for different voltages
Procedure for KVL:
2. Set a particular value in RPS.
3. Note all the voltage reading
4. Repeat the same for different voltages Kcl

Calculation
Slno Reading of
ammeter 1 (I1)
Reading of
ammeter 2 (I2)
Reading of
ammeter 3(I3)
I2+I3
1
2
3
4
Slno Reading of
voltmeter 1(V1)
Reading of
voltmeter 2
(V2)
Reading of
voltmeter 3(V3)
V2+V3
1
2
3
4
Apply the loop and nodal analysis calculate theoretical value of current and voltage from
network

Experiment 2 Measurement of current, power and power factor of
incandescent, lamp, fluorescent lamp, CFL and LED lamp.
Aim: Measurement of current, power and power factor of incandescent lamp, fluorescent lamp,
CFL and LED lamp.
Apparatus Required:
1 Fluorescent tube 40W 1
2 Starter 5A 1
3 Choke coil 10A,230V 1
4 Wattmeter 2500,250V,10A 1
5 Voltmeter ammeter 250v,10/20A 2
Figure 1 fluorescent lab

Theory:
1. The electrode of the starter which is enclosed in a gas bulb filled with argon gas, cause
discharge in the argon gas with consequent heating.
2. Due to heating, the bimetallic strip bends and causes in the starter to close. After this, the
choke, the filaments (tube ends) to tube and starter becomes connected in series.
3. When the current flows through the tube end filaments the heat is produced. During the
process the discharge in the starter tube disappears and the contacts in the starter move apart.
4. When sudden break in the circuit occur due to moving apart of starter terminals, this causes a
high value of e.m.f to be induced in the choke.
5. According to Lenz‟s, the direction of induced e.m.f in the choke will try to oppose the fall of
current in the circuit.
6. The voltage thus acting across the tube ends will be high enough to cause a discharge to occur
in the gas inside the tube. Thus the starts giving light.
7. The fluorescent lamp is a low pressure mercury lamp and is a long evacuated tube. It contains
a small amount of mercury and argon gas at 2.5 mm pressure. At the time of switching in the
tube mercury is in the form of small drops. Therefore, to start the tube, filling up of argon gas is
necessary. So, in the beginning, argon gas starts burning at the ends of the tube; the mercury is
heated and controls the current and the tube starts giving light. At each end of the tube, there is a
tungsten electrode which is coated with fast electron emitting material. Inside of the tube is
coated with phosphor according to the type of light.
8. A starter helps to start the start the tube and break the circuit. The choke coil is also called
blast. It has a laminated core over which enameled wire is wound. The function of the choke is to
increase the voltage to almost 1000V at the time of switching on the tube and when the tube
starts working, it reduces the voltage across the tube and keeps the currents constant.
Procedure:
1. Give the connections as per the circuit diagram
2. Fix the tube holder and the choke in the tube.
3. The phase wire is connected to the choke and neutral directly to the tube.
4. Connect the starter in series with the tube.
5. Switch on the supply and check the fluorescent lamp lighting.

Tabular column
Slno Current Voltage Power Power factor
Power P=VICOS from above equation calculate power factor of different lamp

Experiment no 3 Impedance calculation and verification for R-L and R-C
circuits- using decade boxes.
Aim Impedance calculation and verification for R-L and R-C circuits- using decade boxes.
Apparatus Required
Slno Components Range/type Quantity
1 Voltmeter 0-300V MI 1
2 Ammeter 0-10A MI 1
3 Wattmeter 300V 10A UPF/LPF 1
4 Autotransformer 1KVA 230V 1
5 Resistance inductance
and capacitance box
1
6 Connecting wire As per requirement
Theory:
Power in an electric circuit can be measured using a wattmeter. A wattmeter consists of two
coils, namely current coil and pressure coil or potential coil. The current coil is marked as ML
and pressure coil is marked as CV. The current coil measures the quantity that is proportional to
The current in the circuit and the pressure measures quantity that is proportional to voltage in the
Circuit. An ammeter is connected in series to the wattmeter to measure the current. A voltmeter
is connected in parallel to wattmeter to measure voltage. The power factor of the circuit is
calculated using the relation given below:
Circuit diagram
With resitive load

Procedure:
1. Connect the circuit as shown in the circuit diagram
2. Switch on the supply and vary the auto transformer to build the rated voltage.
3. Vary the load according to current values are increases linearly for different ratings.
4. Note down the ammeter, wattmeter readings. Voltage will maintain constant.
5. After taking all the reading, bring the voltage back to minimum in the auto transformer.
6. Switch off the power supply. Remove the connections.
7. Calculate the power factor by the given formula
Procedure with RL/RC decade’s boxes
1. Connect the circuit as shown in the circuit diagram
2. Switch on the supply and vary the auto transformer to build the rated voltage.
3. Observe the reading of ammeter, voltmeter and wattmeter for various load values.
4. Vary the load according to current readings. Voltage is maintained constant.
5. After taking all the reading, bring the voltage back to minimum in the auto transformer.
6. Switch off the power supply.
7. Calculate the power factor by the given formula.
Actual power = OR x multiplication factor
Apparent power = VI watts
Power factor, Cos = (Actual power) / (Apparent power)

Tabular column
Slno Current Voltage Power Power factor Impedance
Z= Z=V/I cosR/Z

Experiment 4 Load test on a single phase transformer.
Aim Load test on a single phase transformer.
Apparatus Required
1 Ammeter 0-10A 2
2 Voltmeter 0-250V 2
3 Wattmeter 2500W,250V,10A 2
4 Resistive load - 1
5 Auto
transformer
- -
6 Connecting
wire
- -
Procedure
1) Connection are made as for circuit diagram
2) Switch on the DPST switch and vary the voltage with the help of autotransformer apply
rated voltage
3) Apply initial load with certain kw
4) Record the corresponding ammeter voltmeter and wattmeter reading
5) Repeat the step 3 for different load note down reading
6) Calculate efficiency and output power for given transformer

Tabular column
Load
in kw
Voltage Current W1
wattmeter
W2
wattmeter
Input
power
Output
Power
Efficiency
V1 V2 I1 I2

Experiment 5 Voltage and Current relationships of three phase star/delta
circuits.
Aim: Voltage and Current relationships of three phase star/delta circuits.
Apparatus Required
1 Voltmeter 0-250/500V 1
2 Ammeter 0-10/20A 1
3 Resistive load 2/3KW 1
4 Connecting
wire
Theory: refer the text book basic electrical engineering by B.L.Theraj volume 1
Circuit diagram

Procedure:
2) Switch on three phase ac supply and apply the voltage with the help of autotransformer to
rated voltage autotransformer
3) Close the load switch and apply load of some Kw and record the voltmeter and ammeter
reading
4) Using relation of star connected circuit voltage and current formula to calculate parameter
Voltage Current Power Active power Reactive power

Experiment no 6 Measurement of three phase power using two wattmeter
methods.
Aim Measurement of three phase power using two wattmeter methods.
Apparatus Required
1 Ammeter 0-10A 1
2 Voltmeter 0-250/500V 1
3 Wattmeter 2500,250V,10A 2
4 Load resistive 2kw 1
5 Connecting
wire
BRIEF THEORY: The connection diagram is shown in figure below. The sum of two wattmeter
readings gives the total power of the circuit irrespective of the fact that the circuit is balanced or
unbalanced and star-connected or delta-connected. The total power is given as the sum of two
wattmeter readings W1 and W2.
Total power of the load P = W1 + W2.
Precautions:
 THE TPST switch must be kept open initially.
 Load must not be applied while starting.

PROCEDURE:
(i) Connect the circuit as per circuit diagram.
(ii) Vary the load.
(iii) Note down all the readings carefully in the observation table.
(iv) If one wattmeter reads negative or gives reverse readings, the readings of the wattmeter are taken
by reversing the current coil terminal.
Tabular column
Voltage Current Power W1 Power W2 Power factor

Experiment no 7 Two way and three way Control of lamp and formation of
truth table.
Aim: To control a single lamp from two different places.
Apparatus Required
Slno Apparatus Quantity
1 Incandescent lamp 1 230v 40 w
2 Lamp holder 1
3 Two way switch 2 230V 5A
4 Connecting wires As required
Theory
1. A two way switch is installed near the first step of the stairs. The other two way switch is
installed at the upper part where the stair ends.
2. The light point is provided between first and last stair at an adequate location and height if the
light is switched on by the lower switch. It can be switched off by the switch at the Top or vice
versa.
3. The circuit can be used at the places like bed room where the person may not have to Travel
for switching off the light to the place from where the light is switched on.
4. Two numbers of two-way switches are used for the purpose. The supply is given to the switch
at the short circuited terminals.

5. The connection to the light point is taken from the similar short circuited terminal of the
Second switch. Order two independent terminals of each circuit are connected through Cables.
Procedure:
2. Verify the connection
3. Switch on the supply
4. Verify the conditions
Switch s1 Switch 2 States

8. Load test on three phase induction motor
Apparatus Required
Slno Apparatus Specification range Quantity
1 Voltmeter 0-500V
2 Ammeter 0-10A
3 Wattmeter 2500W,250/500V,10/20A
4 Autotransformer
5 Load 3 phase resistive load
3kw
Theory:refer basic electrical technology by B.L.Thearaj Volume II
Circuit diagram
Nature of graph

Procedure
1. Connection are made as for circuit diagram
2. Keeping load switch is in open position close the supply switch run the 3 phase induction
motor with the help of 3 phase autotransformer by applying rated voltage
4. Now close the load switch apply the load in steps up to rated current of induction motor and
note down corresponding readings
5. Discharge the load in steps open the load switch by reducing supply voltages open supply
switch
6. Plot the graph of speed efficiency power factor and torque against output power
V in
volts
I in
amps
W1
in
watts
W2
in
watts
Pin
watts
Pout
in
watts
N in
rpm
Torque Cos
pi
%efficiency
pout/pin
F1
In
kg
F2
in
kg

DEMONSTRATION EXPERIMENT
Demonstration of fuse, MCB by creating a fault.
Apparatus required
Slno Apparatus Specification Range Quantity
1 Ammeter 0-5/10A
2 Voltmeter 0-250V
3 Fuse element Lead tin/copper
4 Load Resitive
Theory : refer basic electrical technology by B.L.Thearaj Volume II
Circuit diagram
Procedure
2) Switch on DPST switch
3) Apply load till fuse element burn or rated current of fuse element
4) Identify the burning or breaking of fuse element

Miniature circuit breaker
Procedure similar as fuse element

Text Books:
1. Basic Electrical Engineering, D C Kulshreshtha, Tata McGraw Hill, Revised First Edition..
2. Principles of Electrical Engineering & Electronics, V.K. Mehta, Rohit Mehta, S.Chand,
Publications
3. .Fundamentals of Electrical Engineering and Electronic, B. L. Theraja, S. Chand & Company
Ltd, Reprint Edition 2013.

basic electrical manual 18 scheme

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to basic electrical manual 18 scheme

Similar to basic electrical manual 18 scheme (20)

Recently uploaded

Recently uploaded (20)

basic electrical manual 18 scheme