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1. RESIDENTIAL HOUSE WIRING USING SWITCHES, FUSE, INDICATOR AND LAMP

AIM: To construct and test basic household wiring using switches, fuse and indicator lamp. COMPONENTS REQUIRED 1. Two switches 2. Two Incandescent lamps 3. Wires 4. One wooden board 5. Three clamps

THEORY

Every conductor switches and other accessories should be of

proper capacity to be capable of carrying the maximum current

through it. All conductors should be of copper or aluminium. In

power circuit, wiring should be designed for the load which it is

supposed to carry. Power sub-circuits should be kept separate

from lighting and fan sub- circuits. Wiring should be done on the

distribution system with main and branch distribution board at

convenient physical and electrical load centre. Wiring should look

neat and have good appearance.

Wires should pass through a pipe or box and it should not twist or cross.

The conductor is carried in a rigid steel conduit confirming to standards or in a porcelain tube.

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PROCEDURE

ONE LAMP CONTROLLED BY ONE SWITCH 1. The circuit connections are given as per Fig (1). 2. Switch on the 230V, 1-Φ, and 50Hz main supply and close the

switch S1 (one way switch type). 3. Now, the lamp will glow and hence the connection of one lamp

by one switch is checked.

TWO LAMPS CONTROLLED BY TWO SWITCHES

1. The circuit connections are given as per Fig (2). 2. Switch on the 230V, 1-Φ, and 50Hz main supply and close the

switches S1 and S2 (one way switch type). 3. Now, the lamps will glow and hence the connections of two

lamps by two switches are checked.

3

1Φ, 230 V, 50Hz

AC supply

Switch S1

SS1

Lamp

60 W

P

N

Fig.1 ONE LAMP CONTROLLED BY ONE SWITCH

• •

4

RESULT: Thus the residential house wiring was constructed using switches,

fuse, indicator and lamps.

1Φ, 230 V,50Hz AC supply

Switch S1 Switch S2

Lamp 60 W

P

N

Fig. 2 TWO LAMPS CONTROLLED BY TWO SWITCHES

• •

• • Lamp

60 W

5

2. FLUORESCENT LAMP WIRING

AIM:

To construct a fluorescent lamp wiring using necessary

components and to test the working of the fluorescent lamp.

COMPONENTS REQUIRED

1. Fluorescent tube light frame – 1 set ( 40 W, 230 V)

2. Connector (2 way) – 1 No.

3. PVC copper cable – As required

4. Starter

5. Choke

6. Fluorescent tube

TOOLS REQUIRED

1. Wireman’s tool kit – 1 No.

2. Nose plier – 1 No.

3. Hand drilling machine with 6.3 mm drill bit – 1 No.

4. Test lamp – 1 No.

CONSTRUCTIONAL DETAILS OF FLUORESCENT LAMP It consists of fluorescent tube, starter, choke, and two way

connectors. They are explained as follows:

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(i) FLUORESCENT TUBE

The fluorescent tube of length varying from 2 to 4 feet is

filled with low pressure argon and a drop of mercury.

(ii) STARTERS

There are two types of starters.

(1) Glow type

(2) Thermal type

GLOW TYPE

It consists of a pair of bimetal contacts sealed in a small

glass bulb filled with argon gas. When supply is given, the whole

mains voltage appears between the open contacts producing an

arc discharge. The heat from the discharge closes the bimetal

contacts, causing the pre-heat current to flow. The closer of

contacts extinguishes the arc. The bimetal contacts cool and the

contact again opens, make the lamp to strike. A small capacitor

fitted between the contact connections outside the glass bulb

avoids radio interference.

THERMAL TYPE

It is also a pair of bimetal contacts, but these are initially

closed and not open as in the glow starter. The contacts are

sealed in a glass bulb together with a small heater coil. The bulb

is filled with a suitable gas to improve the thermal link between

the heater coil and the contacts. When supply is given, current

flows through the lamp cathodes, the choke and the heater coil in

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the starter switch. The heater coil raises the temperature of the

bimetal contacts and they separate, intercepting the current

through the choke, and the consequent voltage pulse causes the

lamp to strike. When the lamp starts, current flows through the

starter heater and the bimetal contacts remain open. This form of

switch is more complicated than the glow switch, but is useful

where a larger preheating time is required. The thermal starter is

useful in fluorescent tubular lamps and sodium lamps.

(iii) CHOKE COIL:

It is an iron cored inductance coil. It has two functions.

They are:

(a) To provide a very high voltage (many times higher than

supply voltage) to start the ionization process in the lamp.

(b) To limit the current through the circuit when the tube is

operating.

(iv) CONDENSER The condenser is provided in the lamp in order to improve

the power factor.

WORKING PRINCIPLES OF FLUORESCENT LAMP

The fluorescent lamp circuit is given Fig (4). When supply

is switched ON, the current heats the filaments initiating

emission of electrons. After 1 or 2 seconds, the starter switch

gets opened, making the choke to induce a momentary high

voltage surge across the two filaments. Due to this, ionization

takes place through argon gas. Mercury vapour arc provides a

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conducting path between the electrodes. The starter used may

be of thermal or glow type whose function is to complete the

circuit initially for preheating the filaments and then to open the

circuit for inducing high voltage across choke for initiating

ionization.

1. TESTING OF CHOKE

Check the choke for its short and open with a test lamp as

shown in Fig (1) and record the results and compare with the

following table.

S.No. STATE OF THE LAMP GLOW CONDITION OF THE CHOKE

1 Normal glow Internal short circuit in choke

2 Dim Good working condition of the choke

3 No glow Open circuit in the choke

2. TESTING OF STARTER

To test the starter, connect the starter with a series test

lamp as shown in the Fig.(2)

Observe the flickering of the lamp which indicates the

good condition of the starter.

If there is no flickering in the test lamp the starter is

defective.

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3. TESTING OF FLUORESCENT TUBE

To test the filament on both sides of the fluorescent

tube for its continuity, make the connection as shown

in the Fig (3). If the tube is in good condition, the lamp

will glow normally. If the lamp is not glowing the tube

is burnt out.

Discard the fluorescent tube, if there is open or fused

filament in either side of the tube.

4. ASSEMBLING OF FLUORESCENT LAMP

Assemble the following four fluorescent lamp parts,

follow the circuit given in Fig (4).

1. Fluorescent lamp frame

2. Choke

3. Starter

4. Two-way Connector

Fix up the Fluorescent tube in the connector fixed at the

two ends of the frame.

5. TESTING OF FLUORESCENT LAMP

Connect the Fluorescent Lamp to a 230V, 1-Φ, 50 Hz AC

supply.

Now, the lamp will glow. If not, check for loose contact/

connection.

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TEST LAMP 40W, 240V

1Φ 230 Volt, 50Hz

A.C Supply

STARTER

Fig.2 TESTING OF STARTER

N

L

Fig.1 TEST CIRCUIT FOR CHECKING

CHOKE 40W

TEST LAMP 100W/240V

N

L

1Φ 230 Volt, 50Hz A.C Supply

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Fig.4 FLUORESCENT LAMP

RESULT: Thus the fluorescent lamp wiring was constructed and tested.

1Φ 230 Volt, 50Hz A.C Supply

TEST LAMP100W, 240V

Fig.3 TESTING OF TUBE

P

N

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3. STAIRCASE WIRING

AIM

To control one lamp from two two-way switches in staircase light wiring. COMPONENTS REQUIRED

1. One lamp 2. Two two-way switches

TOOLS REQUIRED

1. Clamps 2. PVC pipes

THEORY One light point is to be controlled by two switches placed at two

different places so that the light can be switched ON and OFF by

either switch. This type of control of lamps is often used in staircase

lighting, where it is necessary that the person going up the stairs

should be able to switch ON and after reaching upstairs should be

able to switch OFF the lamp.

OPERATION The staircase light wiring is shown in the Fig (1).

Two numbers of two way switches are used for staircase light

wiring.

Two-way Switches have a central terminal.

Central terminal of the first switch is connected to the upper

terminal of the second switch.

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Similarly, the central terminal of second switch is connected to

the lower terminal of the first switch.

When the switch 1 is in ON condition and the switch 2 is in

OFF condition, the lamp will not glow and vice-versa.

When both the switches are either ON or OFF, the lamp will

glow.

Therefore, the lamp is controlled from two different switches.

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RESULT: Thus the staircase wiring was constructed and tested.

Switch 1 Switch 2 Lamp 60 W

P

N

Fig.1 STAIRCASE WIRING

•

•

•

•

•

•

1Φ,230 V,50Hz AC supply

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4. CALIBRATION OF VOLTMETER AND AMMETER

AIM:

To calibrate the given voltmeter and ammeter using standard

meters and to draw the graph between percentage error and test

meter readings.

APPARATUS REQUIRED:

S.NO APPARATUS TYPE RANGE QUANTITY

1 Standard

Voltmeter MI (0-300V) 1

2 DPST Switch - - 1

3 Lamp Load - - 1

4 Standard

Ammeter MI (0-10A) 1

5 Test Ammeter MI

(0-10A) 1

6 Test Voltmeter MI (0-300V) 1

PRECAUTIONS:

1. DPST switch in open position.

2. Switches of lamp load in off position.

FORMULA USED:

% Error =(Std Meter Reading – Test Meter Reading) X 100

Std Meter Reading

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THEORY: The measuring process is one in which the property of

an object or system under consideration is compared to an accepted

standard unit.

Ammeters are connected in series in the circuit whose

current is to be measured. Calibration is necessary to check whether

the error is present in the meter by comparing it with a standard

meter and to calculate the percentage error.

Voltmeters are connected in parallel with the circuit

whose voltage is to be measured.

PROCEDURE:

1.Calibration of Voltmeter:

a. The connections are given as per the circuit diagram

shown in fig (1).

b. Switch on the 1, 230V, 50Hz AC supply.

c. Set the input voltage to some value , say 50V, by

using the auto transformer.

d. Note down the value of voltage in both standard and

test meters and enter the value in Table (1).

e. Calculate the % error by using the formula.

f. Increase the voltage in steps of 50V and repeat the

steps from d to e.

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2.Calibration of Ammeter:

a. The connections are given as per the circuit diagram

shown in fig (2).

b. Switch on the 1, 230V, 50Hz AC supply.

c. Set the load current to some value, say 2A, by using

the variable resistive load.

d. Note down the value of load current in both standard

and test meters and enter the value in Table (2).

e. Calculate the % error by using the formula.

f. Increase the load current in steps of 2A and repeat

the steps from d to e.

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230V, 1Φ,

50Hz,AC

Supply

N

P

D

P

S

T

S

W

I

T

C

H

V

10 A

(0-300) V

MI (0-300) V

MI

TEST

METER

STD METER

Auto Transformer

230V / (0-270V)

Fig (1)

NL

FUSE

Fig (1). Calibration of Voltmeter.

V

V

V

19

230V,1Φ,

50Hz,AC

Supply

(0-10) A

MI

N

P

D

P

S

T

S

W

I

T

C

H

V

A

10 A

(0-300) V

MI

RESISTIVE

LOAD

Auto Transformer

230V / (0-270V)

Fig (1)

A

(0-10) A, MI

TEST

METER

STD

METER

NL

FUSE

Fig (2). Calibration of Ammeter

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TABLE(1):

Calibration of Voltmeter:

S. No Test Meter Reading

(Volts)

Standard Meter Reading

(Volts) % Error

1

2

3

4

TABLE(2):

Calibration of Ammeter:

S. No Test Meter Reading

(Amps)

Standard Meter Reading

(Amps) % Error

1

2

3

4

21

MODEL GRAPH:

Fig (3).Calibration of Voltmeter

Fig (4).Calibration of Ammeter

RESULT:

The given voltmeter and ammeter were calibrated using the

standard meters and the graphs were drawn.

% E

rror

Test Meter Reading (V)

% E

rror

Test Meter Reading (A)

% E

rror

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5. MEASUREMENT OF POWER USING WATTMETER

AIM:

To conduct the experiment on Measurement of Power using

Wattmeter.

APPARATUS REQUIRED:

S.NO APPARATUS TYPE RANGE QUANTITY

1 Wattmeter UPF 300 V, 15A 1

2 DPST Switch - - 1

3 Lamp Load - - 1

PRECAUTIONS:

1. DPST switch in open position.

2. Switches of lamp load in off position.

THEORY:

Wattmeter is a device which is used to measure the power in AC

circuits directly. i.e. Wattmeter gives the direct indication of power

and there is no need for multiplying two readings as in the case when

voltmeter and ammeter is used.

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PROCEDURE:

1. The connections are given as per the circuit diagram shown

in fig (1)

2. Switch on the 1, 230V, 50Hz AC main supply and close the

DPST switch.

3. Switch on the Lamps one by one and note down the

corresponding wattmeter readings in the Table.

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Fig(1). Circuit Diagram for Measurement of Power using Watt meter

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TABLE:

S.No Load Connected

(Watts)

Measuring Power in watts

using Wattmeter

1 40W

2 60W

3 100W

4 .

. .

. .

RESULT:

The power was measured using wattmeter.

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6. MEASUREMENT OF ENERGY USING SINGLE PHASE ENERGY METER

AIM:

To conduct the experiment on measurement of energy using

single-phase energy meter.

APPARATUS REQUIRED:

S.NO APPARATUS TYPE RANGE QUANTITY

1 Energy meter Induction 1 1

2 DPST Switch - - 1

3 Stop Clock - - 1

4 Lamp Load - - 1

PRECAUTIONS:

1. DPST switch in open position.

2. Switches of lamp load in off position.

FORMULA USED:

Measuring Energy in KWH = N/K

Where,

N= Number of revolutions 15 sec.hu

K= Energy meter constant. (Rev/KWH)

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THEORY:

Induction type Energy Meter are universally used for measurement

of energy in domestic and industrial a.c. circuits. Induction type of

meters possess lower friction and higher torque ratio/weight ratio.

And their also inexpensive and accurate and retain their accuracy

over a wide range of loads and temperature conditions.

PROCEDURE:

1. The connections are given as per the circuit diagram

shown in fig (1).

2. Note down the energy meter constant in the Table.

3. Switch on the 1, 230V, 50Hz AC main supply and close

the DPST switch.

4. Set the load current to 2A and note down the

corresponding time for 5 revolutions in the Table.

5. Calculate the number of revolutions for 15sec and enter

the corresponding values in the Table.

6. Calculate the energy using the formula.

7. Increase the current in steps of 1A and repeat the steps

from 5 to 6.

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Fig(1) Circuit Diagram for Measurement of Energy using Energy meter

VARIABLE

RESISTIVE

LOAD

29

TABLE:

Energy meter constant (K) = Rev/ KWH

S.No Load

Current (Amps)

Time for 5

revolutions (T)

(sec)

Number of Revolutions

for 15sec N = (5/ T) x 15

Measuring Energy

in KWH

= N/K

1

2

3

4

5

RESULT:

The Energy was measured using Energy meter.