new first year electrical lab manual

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MEASURMENT OF VOLTAGE, CURRENT, POWER AND POWER FACTOR USING RLC LOAD

Aim: To measure power in a single phase AC circuit using wattmeter by RLC loading. APPARTUS REQUIRED:

SL.No Name of the Apparatus Range / Type Quantity

1 Voltmeter (0-300V) MI 1 No.

2 Ammeter (0-10A) MI 1 No.

3 Wattmeter 300V,10A,LPF 1 No.

4 RLC Load 5kW 1 No.

5 Connecting Wires 1/18 SWG As per requirement

THEORY:

Power in an electric circuit can be measured using a wattmeter. A

wattmeter consists of two coils, namely current coi l and pressure coil or potential

coil. The current coil is marked as ML and pressure coil is marked as CV. The

current coil measure the quantity that is proportio nal to the current in the circuit

the pressure coil measures quantity that is proport ional to the voltage in the

circuit. The given wattmeter is loaded by direct lo ading. The ammeter is

connected in series to the wattmeter. Since the sam e current flows in both the

coils, the current and voltage across the circuit a re constant. The power

consumed by the load is measured using the wattmete r and calculated using the

relation given below.

Expt No: Date:


CIRCUIT DIAGRAM:

AA ∼∼

VV ∼∼

Autotransformer 230V/(0-270)V

11 φφφφφφφφ 223300VV AACC SSuuppppllyy

5500HHzz

P

N

((00--330000))VV,, MM II

((00--1100))AA,, MM II

MM

CC

LL

VV

FFuussee

NNLL

RRLLCC LLOOAADD

((330000VV,, 1100AA,, LL PPFF))

DPST S


FORMULAE:

Actual power = W x Multiplication factor

Where W – Observed wattm eter reading

Apparent power = VI watts

Where V – Voltmeter reading

I – Ammeter reading

Power Factor, cos φφφφ = Actual Power / Apparent Power

PROCEDURE:

1. Connect the circuit as shown in the circuit diag ram.

2. Initially no load is applied.

3. Autotransformer is set to minimum voltage positi on before switching on

the power supply.

4. Set the rated voltage by using the autotransform er. Measure and record the

values of voltmeter, ammeter and wattmeter on no lo ad condition. Also

carefully note the multiplication factor of the wat tmeter that is mentioned in

the wattmeter itself.

5. Apply the load by adjusting RLC load.

6. Measure and record the values of voltmeter, amme ter and wattmeter.

7. Repeat the steps 5 and 6 until the ammeter readi ng reaches 10A.

8. After taking all the readings, reduce the load s lowly to the minimum and

bring the voltage to minimum in the autotransformer . Switch off the power

supply.

9. Calculated the Indicated power by the given form ula.

10. Calculate the power factor by the given formula .


OBSERVATION TABLE:

Multiplication Factor=

Sl.No Voltage

V (V)

Current

I (A)

Wattmeter Reading

(watts) Actual Power

(watts)

Power Factor

cosφφφφ Observed Actual

MODEL CALCULATION:

Result

A single – phase wattmeter is used to measure powe r in AC circuit using

RLC loading.


HOUSE WIRING

Aim: To Construct House wiring using Energy Meter METERIALS REQUIRED:

Sl.No

Name of the apparatus

Range / Type

Quantity

1 Switch SPST, 5A 3 Nos.

2 Incandescent Lamp 100W 1 No.

3 Lamp Holder Batten 1No.

4 Ceiling rose - 1No.

5 Socket 10A 1No.

6 Screws 1inch As per required

7 Wires 1/18SWG As per required

8 Switch Board 12″″″″ x 8″″″″ 1No.

9 Energy Meter 1 φφφφ 300V , 16A 750 rev 50Hz

1No.

10 Main switch Box 1 φφφφ 300V , 16A 1No.

EExxpptt..NNoo:: DDaattee::


TOOLS REQUIRED:

Sl.No Name of the tools Quantity

1 Combination Plier s

1 No.

2 Connector screw driver 1 No.

3

Screw driver 1 No.

4 Electrician knife 1 No.

THEORY:

Conductors, switches and other a ccessories should be of proper

capable of carrying the maximum current which will flow through them. The

following table shows the rating for different acce ssories. Conductors should be

of copper or aluminium. In power circuit, wiring sh ould be designed for the load

which it is supposed to carry. Power sub circuits s hould be kept separate from

lighting and fan sub – circuits. Wiring should be d one on the distribution system

with main and branch distribution boards at conveni ent centers. Wiring should

neat, with good appearance.

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

� The conductor is carried in a rigid steel conduit c onforming to standards or

in a porcelain tube.


CIRCUIT DIAGRAM:

EENNEERRGGYY MM EETTEERR

MM AAII NN SSWWII TTCCHH

Lamp 100W

11 φφφφφφφφ 223300VV AACC SSuuppppllyy

5500HHzz

PP

NN

SS11 SS22 LL 22 LL 11

Ceiling rose

Switch Board

DDPPII CC

DPIC – Double Pole Iron – Clad Switch


PROCEDURE:

1. Study the given wiring diagram

2. Make the location points for energy meter, main witch box,

switchboard, lamp and ceiling rose.

3. Draw the lines for wiring on the wooden board.

4. Place the wires along with the line and fix.

5. Fix the bulb holder, Switches, Ceiling rose, Soc ket in marked

positions on the wooden board.

6. Connect the energy meter and main switch box in marked positions

on the wooden board.

7. Give a supply to the wires circuit.

8. Test the working of light and socket.

Result:

Thus the wiring for the bulb and ceiling rose was prepared and

tested.


STAIRCASE WIRING

Aim: To control the status of the given lamp by using t wo – way switches METERIALS REQUIRED:

Sl.No


Range / Type

Quantity

1 Incandescent Lamp 100W 1 No

2 Lamp Holder Pendent Type 1 No

3 SPDT Switch 230V,5A 1 No

4 Wires 1/18” As per requirement

5 P.V.C Pipe 1/4" As per requirement

6 Wooden Board - 1 No

7 Round block - 1 No

TOOLS REQUIRED:


1 Combination Plier 1 No

2 Connector screw drivers 1 No

3 Screw driver 1 No

4 Electrician knife 1 No

Expt.No: Date:


CIRCUIT DIAGRAM :

SPDT - 1

NN

PP

223300VV,, 5500HHzz AACC SSuuppppllyy

11

22

33

11’’

22’’

33’’

LLaammpp 6600WW,, 223300VV

SPDT - 2


PROCEDURE:

1. Place the accessories on the wiring board as per the circuit diagram.

2. Place the P.V.C pipe and insert two wires into t he P.V.C pipe.

3. Take one wire connect one end to the phase side and other end to the

middle point of SPDT switch 1

4. Upper point of SPDT switch 1 is connected to the lower point of SPDT

switch2.

5. Lower point of SPDT 1 is connected to the upper point SPDT switch2.

6. Another wire taken through a P.V.C pipe and midd le point of SPDT

switch 2 is connected to one end of the lamp holder .

7. Another end of lamp holder is connected to neutr al line.

8. Screw the accessories on the board and switch on the supply.

9. Circuit is tested for all possible combination o f switch position.

PRECAUTIONS:

� While giving the connections be careful

� Handle the lame safely

� Be careful while handling the tools.


SWITCH

POSITION TABLE:

Sl.No

SPDT1 SPDT2 Result

1 12 1’2’ OFF / ON

2 12 2’3’ OFF / ON

3 23 1’2’ OFF / ON

4 23 2’3’ OFF / ON


Result:


FLUORESCENT LAMP WIRING

Aim: To make and check the fluorescent lamp wiring METERIALS REQUIRED: TOOLS REQUIRED:


1 Combination Plier 1 No

2 Connector screw drivers 1 No

3 Screw driver 1 No

4 Electrician knife 1 No

S.No


Range / Type Quantity

1 fluorescent lamp fixture

4 ft 1 No

2 fluorescent lamp 40W 1 No

3 Choke 40W, 230V, 1 No

4 Starter 1 No

5 wires 1/18” As per requirement

Expt..NNoo:: Date:


CIRCUIT DIAGRAM:

Choke 40W, 230V

SS

Starter

PP NN 11φφ,, 223300 VV ,,

5500HHzz AACC SSuuppppllyy

40W Fluorescent lamp Filament Filament


THEORY: Tube light has filament on either side. They are c oated with tungsten

material. The inside of the tube has phosphorous co ating which is used to

convert ultraviolet into visible light and to give the required color sensation. A

choke is used to give transient high voltage so as to initiate the electron

movement which is an iron starter capacitor is used to suppress radio-

interference with the switch closed. The current fl ows through the choke and the

starter. The glow switch suddenly breaks thereby cr eating the circuit. Due to high

conductivity, inductive property of the choke, a tr ansient high voltage is available

across the filament. Hence the electrons are emitte d and travel through the tube.

Then tube light is produced.

PROCEDURE:

1. Give the connections as per the circuit diagram as shown in figure.

2. Fix the tube holder and the choke in the tube.

3. The phase wire is connected to the choke and neu tral directly to the

tube

4. Connect the starter in series with the tube.

PRECAUTIONS:

� While giving the connection be careful.

� Handle the lamp safely.

� Be careful while handling the tools.

� All the connections should be right and tight.

Result:


MEASURMENT OF ENERGY USING ENERGYMETER

Aim: To measure the energy in a single in a phase phase circuit using direct loading APPARTUS REQUIRED:

SL.No Name of the Apparatus Range / Type Quantity

1 Single phase Energy meter 750 rev / kWh, 240V, 50Hz 1No.

2 Wattmeter 300V, 10A, UPF 1No.

3 Voltmeter 300V, MI 1No.

4 Ammeter 10A, MI 1No.

5 Load Resistive, 5kW 1No.

6 Wires 1 / 18 SWG As per requirement

THEORY:

The energy meter is an integrated type of instrume nt, where speed of

rotation of the aluminum to the power consumed and number of revolutions per

minute is proportional to the energy consumed by th e load.

The ratings associated with the energy meter are.

� Voltage rating

� Current rating

� Frequency rating

� Meter Constant

Expt No: Date:


The driving system of the meter provides the rotati onal surface of the torque for

the moving system, which in turn activates the ener gy meter. The energy meter is

operated at induction principle in which eddy curre nt.


CIRCUIT DIAGRAM:

DPSTS

AA ∼∼

VV ∼∼ 1 φφφφ

230V Ac Supply

50Hz

1 φφφφ Autotransformer

(0-270V)

(0-10A) MI

(0-300V)

MI

S1

S2

L1

L2

M

C

L

V

Fuse

NL

Resistive load 5 KW

P

N


Indicated in the aluminum disc interacts with the main field and creates the

driving force.

FORMULAE:

Energy meter specification = 750 rev / kWh

True energy = Power (P) x time (s)

= P x t (ws)

= P x t / 3600 x 1000 kWh

Measured energy = n / 750 kWh

Where n - number of revo lutions / sec

`

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Supply is given to the switch by closing the DFS T switch.

3. By adjusting the voltage is brought to the rated voltage.

4. Load is switched On

5. Time taken for five revolutions in the energy me ter is noted and the

corresponding ammeter and voltmeter reading are not ed.

6. The above procedure is repeated for different lo ad current and for fixed

number of revolutions.

7. Then the load is gradually released and supply i s switched OFF.


OBSERVATION TABLE:

M.F ----------------

Sl. No

Supply

Voltage

V

Load Current

I (A)

Wattmeter

Reading

P (W)

Time

t (sec)

True Energy

p x t

1000 x 3600

(kWh)

Measured

energy

n / 750 (kWh)

MODEL CALCULATIONS:


Result:

Thus the energy in a single phase was measured usi ng energy meter.

new first year electrical lab manual

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