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8/13/2019 Lm Ece Ew Manual 01112012
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ELECTRICAL
WORKSHOP LAB
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ELECTRICAL WORKSHOP LAB
This laboratory gives an exposure to students in their third semester on basic
electrical devices and fittings like mercury vapour lamp, energy meter, MCBs, etc.
Through this, the students shall be able to appreciate the intricacies involved indomestic and industrial electrical wiring.
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LIST OF EXPERIMENTS
1. INTRODUCTION OF TOOLS, ELECTRICAL MATERIALS, SYMBOLSAND ABBREVIATIONS.
2. TO MAKE T JOINT AND STRAIGHT JOINT.3. TO STUDY STAIRCASE WIRING.4. TO STUDY HOUSE WIRING.5. TO STUDY FLUORESCENT TUBE LIGHT.6. TO STUDY HIGH PRESSURE MERCURY VAPOUR LAMP (H.P.M.V.).7. TO STUDY SODIUM VAPOUR LAMP.8. TO STUDY SINGLE PHASE INDUCTION MOTOR USING SINGLE
PHASE ENERGY METER AND DOUBLE POLE MAIN SWITCH.
9. TO STUDY THREE PHASE INDUCTION MOTOR USING THREE PHASEENERGY METER, TRIPPLE POLE IRON CLAD MAIN SWITCH AND
DOL STARTER.
10.TO STUDY REPAIRING OF HOME APPLIANCES SUCH AS HEATER,ELECTRIC IRON AND FANS ETC.
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EXPERIMENT- 1
AIM:Introduction of tools, electrical materials and abbreviations.
TOOLS
PLIER: Generally three types of pliers are used in the electrical workshop. They are:-
FLAT NOSE PLIER: Used for holding jobs or holding wires. It has got only two slottedjaws, which are tapered. Thus it is used for tightening or loosening small nuts.
SIDE CUTTING PLIER: Used for cutting of thin wires and removing insulations fromthem. It has got cutting edge on its one of its sides.
ROUND NOSE PLIER: Used only to hold or cut the wires. It has no gripping jaws. Itscutting edge is long and rounded on the top.
SCREW DRIVER: It is used to loosen or tighten or to keep screws in position. It has a woodenor plastic handle and a blade of high carbon steel.
CHISEL:
FIRMER CHISEL: Generally used for carpentry works and can be used by hand pressureor with the help of mallet. It has flat blade, which varies from 12mm to 15mm.
COLD CHISEL: Used for cutting iron pieces (cold). It has cutting angle from 30to45and is made of high carbon steel.
HAMMER: Most commonly used in the workshop. The head is made of cast iron or forged; theclaw is hardened and tampered. The striking place is slightly convex. The head is fitted with a
wooden handle of various lengths.
HACKSAW:Used to cut metal such as iron strips, core pipes etc. it has a blade made of high
steel or tungsten.
ELECTRICAL TOOLS
TUMBLER SWITCH: (6 A for light), this switch was used 3-4 decade ago. It is made of
Bakelite.
MCB BOX:Known as the Miniature Circuit Breaker Box.
METAL CONDUIT PIPE WITH JUNTION BOX: Metallic hollow pipe, which is used as a
passage for electrical house, hold wires. It is fixed to walls with the help of metallic saddle.
METAL BEND: Hollow metallic pipe bend to an angle of 90to allow smooth movement ofwires inserted through the walls during wiring .
BATTEN WIRING: It is an old fashioned wiring used 4-5 decades ago.
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PVC CASING AND LAPPING: Long rectangular box made of 2 parts. It is made of PVC and
used mainly to pass wires through walls during wiring.
PVC BEND:Work similarly as metal bends but it is made up of PVC that makes it lighter,
cheaper and more durable.
BATTEN LAMP HOLDER:mainly used to hold electric bulbs and lamps.
SWITCH BOARD WITH SWITCHES: it contains the following:
SOCKET OUTLETS: it is a type of electrical material through which electric currentflows from wires to various electrical appliances. It is of 6A.
TWO WAY SWITCH: it is mainly used in staircase wiring to either on or off the light.It is of 6A.
ONE-WAY SWITCH: it is a device used to switch on lights of 6A.7/20 SWG (POWER WIRE): they are used in power purposes for duty electrical appliances.7/20 means 7 numbers of wires in the cable and 20 strands for thickness or gauge size.
3/20 SWG (PHASE WIRING): mostly used for house wiring purposes.
3/22 SWG (NEUTRAL WIRE): it is also used for house wiring purposes.
1/18 SWG: it is used for earthing.
FLEXIBLE CABLE: This is a temporary wire used for both power and light but temporarily. It
is used as extension wire.
ABBREVIATIONS:
S.NO.
1.2.
3.
4.
5.
6.7.
8.9.
10.
11.12.
13.
14.
NAME OF THE UNIT
VOLTSAMPERES
LOW TENSION
HIGH TENSION
OIL CIRCUIT BREAKER
KILO-VOLTSMAIN SWITCH
SUB-MAIN SWITCHDISTRIBUTION BOARD
IRON CLAD DISTRIBUTION BOARD
CONTROL BOARDSWITCH BOARD
NORMALLY OPEN
NORMALLY CLOSED
ABREVIATION
VAmp
LT
HT
OBC
KVMS
SMSDB
ICDB
CBSB
NO
NC
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15.
16.
17
18.19.
20.
21.22.
23.
24.25.
26.
27.
28.29.
30.
31.
32.33.
34.35.
36.
37.
38.39.
40.41.
42.
43.44.
45.
46.47.
48.
49.50.
51.
52.
53.54.
55.
56.57.
58.
59.60.
61.
62.
TIME DELAY RELAY
NO VOLT RELEASE
SUB-DISTRIBUTION BOARD
OVER LOAD RELEASEDIRECT ON LINE
DOUBLE POLE IRON CLAD
ALL ALLUMINIUM CONDUCTORALTERNATING CURRENT
DIRECT CURRENT
TRIPLE POLE IRON CLADAIR CIRCUIT BREAKER
CURRENT TRANSFORMER
CAB TYPE SHEATHED
CAPACITIVE VOLTAGE TRANSFORMEREARTH LEAKAGE CIRCUIT BREAKER
EXTRA HIGH VOLTAGE
ELECTROMOTIVE FORCE
FIELD EFFECTIVE TRANSISTORHIGH PRESSURE Hg VAPOUR LAMP
HIGH RAPTURE CAPACITY FUSEHIGH VOLTAGE
LOW VOLTAGE
INTRIGATED CIRCUIT
JUNCTION FIELD EFFECT TRANSISTORKILO VOLT AMPERE
KILO WATTKILO WATT HOUR
LIGHTENING ARRESTER
LIGHT DEPENDENT RESISTANCELOW PRESSURE Hg VAPOUR LAMP
LOW VOLTAGE
LIGHT EMITTING DIODEMINIATURE CIRCUIT BREAKER
METAL OXIDE FIELD EFFECT TRANSISTOR
MEGA WATTNEUTRAL LINK
OVER LOAD TRIP COIL
PHASE
POTENTIAL TRANSFORMERPOLYVINYL CHLORIDE
PAPER INSULATED LEAD COVERED
SERIESSHUNT
SILICON CONTROL SWITCH
LIGHT ACTIVATED SILICON CONTROL SWITCHSUB MAIN SWITCH
SINGLE POLE
SINGLE POLE DOUBLE THROW
TDR
NVR
SDB
OLRDOL
DPIC
AACAC
DC
TPICACB
CT
CTS
CVTELCB
EHV
EMF
FETHPMVL
HRCFHV
LC
IC
JFETKVA
KWKWh
LA
LDRLPMVL
LV
LEDMCB
MOFET
MWNL
OLPEC
Ph
PTPVC
PILC
SeSh
SCS
LASCSSMS
SP
SPDT
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63.
64.
65.
66.67.
68.
69.70.
71.
72.73.
74.
75.
76.77.
78.
79.
80.81.
82.83.
84.
85.
SINGLE POLE SINGLE THROW
STANDARD WIRE GAUGE
TRIPLE POLE SWITCH
SODIUM VAPOUR LAMPSODIUM UNILATERAL SWITCH
SILICON CONTROL RECTIFIER
TRIPLE POLE WITH NEUTRALTRIPLE POLE IRON CLAD
TRIPLE POLE DOUBLE THROW
TRIPLE POLE SINGLE THROWTHERMAL RELAY
TOUGH RUBBER SHEATHED
UNIJUNCTION TRANSISTOR
VOLT AMPEREVULCANISED INDIAN RUBBER
WATER TIGHT
WEATHER-PROOF CABLE
CATHODE RAY OSCILLATORRESISTANCE
CAPACITORINDUCTANCE
BATTERY
UNIJUNCTION TRANSISITOR
SPST
SWG
TPS
SWLSUS
SCR
TPNTPIC
TPDT
TPSTTR
TRS
UJT
VAVIR
WT
WPC
CROR
CL
E
UJT
QUIZ/ANSWERS
Q1. What is the abbreviation of kva? Kilo Watt Amperes
Q2. Name the standard of the wires according to their
gauges?
1/8, 3/20, 7/20, 7/22
Q3. What is the use of lamp holder? Hold in particular position
Q4. What is the symbol of the ceiling fan?
Q5. What is the function of hawk saw? To cut pipes, metal sheet &
wooden pieces
Q6. How many types of pliers we used? Flat nose, long nose, cutting
& combination
Q7. What do you meant by RPM? Revolutions per minute
Q8. What is the function of chisel? Cutting metal pieces
Q9. What is the function of screwdriver? According to length of a bit
Q10. Why we use flexible wires? Increasing the length of the
supply cable
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EXPERIMENT -2
AIM: Two make a T joint of Copper 1/18 SWG wire and straight joint of 3/22 SWG wire.
APPERATUS USED: Side-cutting plier, 1/18 SWG and 3/22 SWG wires.
THEORY:T-JOINT:It is used to tape the connection from running horizontal line. It is also known as
parallel joint.STRAIGHT JOINT: it is used to increase the length of the 3 standard wires.
PROCEDURE: T JOINT1. Take 2 horizontal and vertical lengths of wires 30cm and 20cm respectively to which the
joint is to be made.2. Remove the insulation of taping vertical length of 7.5cm3. Remove the insulation of straight length middle portion4. Remove the insulation of 12mm on each side of the base wire.5. Hold the wire at 90 to running and make a neck turn to void slipping of joint6. Wrap off conduction closely and tightly 6-8 turns on horizontal wire.7. Round off the conductor with the help of a plier.8. The joint is soldered and insulated with tape.CIRCUIT DIAGRAM:
(3)
(1)
(4)
(2)
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STRAIGHT JOINT:1. Cut two pieces of cable of nearly the same length.2. Remove the insulation from the end of both the cable pieces.3. Separate the wire from both the cables and join the 2 cables in such a way that the
individual wires are joint separately4. For half of the length of the di-insulated cable overlapped make a trust with the help of a
plier.5. Complete the remaining half-length on the twist with the help of a plier.CIRCUIT DIAGRAM:
(1)
(2)
(3)
(4)
PRECAUTIONS:
1) Tools should be used carefully.2) Fitting should be tightly fitted.3) Connection should be tight.4) Wire should be on the conduit, power gripped properly.5)
QUIZ/ ANSWER
Q1. Why we make a T joint? To tap the supply
Q2. What does you meant by 3/22 SWG? 3 wires &22 is the diameter of
the wire
Q3. What is the application of straight joint? Increase the length of the wire
Q4. What is the main precaution to make the joints? Tight and properly Insulated
Q5. Which joint we use for tap connection from
horizontal line?
T-joint
Q6. Which tool is used for twisting the wires? Plier
Q7. Which joint is used for Fan connection? T-joint
Q8. What is swg. Of earthing wire? 1/18 SWG
Q9. How we increase the length of conductor? Straight joint
Q10. What is the function of a cutter? Cutting cables
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EXPERIMENT -3
AIM:To study staircase wiring.
APPARTUS:3/22 SWG wires, lamp holders, two way switch, 40w bulb 3PVC casing, strips and pliers.
THEORY:It is that wiring which makes use of 2 switches to operate bulb at the beginning of
the stair lights and the bulb gives off by pushing the button in the end. One of the terminals ofthe bulb is connected to the main line whose power line is connected to middle slot of two-way
switch. Remaining first of there slots is connected in parallel as in crossed node.
CIRCUIT DIAGRAM:
(1)
(2)
(3)
(4)
PROCEDURE:
1. Plan the wiring and casing according to the circuit diagram.2. With the help of plier and stripper share the ends of wire of required length.3. Connect the wire carrying the current to the central pin of the two-way switch.4. Connect the remaining ends A and B to the corresponding other two way switch.5. Connect the center pin wire of second two-way switch to the lamp.6. Connect the second point to the neutral for completing the circuit.7. Use PVC case wiring to cover expose wiring.8. Switch ON and OFF the two switches alternatively to the bulb.
PRECAUTIONS:1) Tools should be used carefully.
2) Fitting should be tightly fitted.
3) Connection should be tight.4) Wire should be on the conduit, power gripped properly.
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EXPERIMENT 4
AIM: To study hose wiring.
TOOL USED:Tenon saw screwdriver 8 cm (8), Screwdriver 15(6), connector Screwdriver, Hammer, Plierdrill machine, Try square, chisel, File, Poker knife.
MATERIAL AND QUATITY:1) T.W Batten 19mm x 13mm 42m
2) T.W batten 13mm x 13mm 10m3) CTS/ T.R.S wire 13/. 039(3/22) 250v
4) Batten holder 2 no.
5) Plug 3pin, 5amp 1 no.6) Tumbler Switch one-way 5amp 3 no.
7) T.W round blocks (7.75cm x 2.5) 3 no.
8) T.W board 40 mm(1+1/2)9) Hink clip 40 mm(1/2)
10) Wood Screw
THEORY: This type of wiring is used in houses. The two terminal of supply are connected tometer and other two terminals are joined to DPIC. One end is attached to N-link of fuse is joined
to switch board of a room and neutral pole is also connection to switch board according to our
need.
CIRCUIT DIAGRAM:
LAMP
1 2
N
P
TWO WAY SWITCHTWO WAY SWITCH
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TYPES OF HOUSE WIRING:
1) CLEAT WIRING: - This is of wiring suitable only for temporary wiring purpose. In lampor wet location the wire used should be moisture proof and a weather proof.
2) P.V.C OCNDUCT WIRING:- This uses a conduit pipe for the mechanical protection ofwire. In this system of wiring, wires are carried through P.V.C conduit pipe for giving
converging to pipes conduit pipe has certain advantage like it is moisture proof and durable.3) P.V.C CASTING WIRING: -This type of wiring is mostly used for fixing cables on a
wooden structure called batten by means of metal. It is the surface wiring system whenever
wires are broken for connecting to switch on the right point junction box made up of either
part plastic or metal C.I must be used and provided same means of earthing.4) P.V.C CASTING WIRING: -This type of wiring is mostly used for indoor and domestic
wiring carried through a P.V.C casing wiring
PROCEDURE:
1) Draw the tangent or wiring on the board with cholk.2) Cut the required length of T.W batten file and link chips on then and file the batten withscrew of 3mm size.3) Cut the C.T.S wire in required length and put them on batten gripped by link chips or per
circuit diagram.
4) Fix the T.W round blocks and board after drilling the holes for wire.5) Fix the batten holder, 3-pin plug and switch on round block.6) After completing wiring it should be checked before supplying current.
PRECAUTIONS:
1) Tools should be used carefully.
2) Fitting should be tightly fitted.3) Connection should be tight.4) Wire should be on the conduit, power gripped properly.
QIUZ/ANSWER
Q1. How much voltage in a single-phase supply? AC 230 volt
Q2. What do you meant by DPIC? Double pole iron clad
Q3. What is the bus bar? To take many connections
Q4. How we represent the lamp?
Q5. Why we use regulator? To regulate supply voltage
Q6. What is the max. Load on a switchboard? 10 switches or 1000W
Q7. What is MCB? Miniature circuit breaker
Q8. What is cleat wiring? Used for moist wiring
Q9. What is the colour code of wiring? R-Y-B phase
Q10. What do you meant by PVC? Polyvinyl chloride
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EXPERIMENT 5
AIM: To study fluorescent tube light.
APPARATUS:tube, tube base, starter, choke, and wire.
CONSTRUCTION:Fluorescent tube is a low-pressure mercury vapour lamp. The lamp is in theform of long glass tube due to low pressure, with fluorescent powder coating to its inner surface.Tungsten filaments coated with barium oxide are placed at each side of the tube. The tube
contains small amount of mercury with small quantity of argon gas at low pressure. When the
temperature increases mercury changes into vapour form. At each end of the tube, electrode inspiral form is made of tungsten coated with electrons emitting barium. A capacitor is connected
across the circuit to improve the power factor.
CIRCUIT DIAGRAM:
PROCEDURE:
1. Fix the tube holder and the choke on the tube base.
2. Phase wire is connected in the choke and neutral direct to the tube.3. Fix the fluorescent tube between the holders.
4. Finally connect the starter in series with the tube.
PRECAUTIONS:
1) Tools should be used carefully.
2) Fitting should be tightly fitted.3) Connection should be tight.
4) Wire should be on the conduit, power gripped properly
TUBE ELECTRODES
STARTER
CHOKE
N
230VSUPPLY
C
P
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EXPERIMENT-6
AIM:To study High Pressure Mercury Vapour (HPMV) Lamp.
APPARATUS:HPMV lamp, connecting wires.
THEORY:Light could be of different colours depending upon the wavelength of radiationfalling on material. A HPMV lamp contains mercury at high pressure in a highly evacuated tube.
It is basically based on the discharge tube phenomenon under which electric discharge through
gases takes place at some pressure and perceived as light by our eyes.
The pressure inside the inner tube is 1-2 times of mercury column. A capacitor and choke are
connected in the outer circuit. Chokes function is to limit the current to safety limit, capacitor
increases power factor.
The cause for colour is due to the collision between charged particles and atoms that excite gas
atoms and the gas atoms while returning to the ground state emit light of colours characteristicsof the wavelength of the radiations emitted.
CIRCUIT DIAGRAM:
STARTING ELECTRODE
MAIN ELECTRODE
RESISTANCE
OUTER TUBE
C
P
230V
SUPPLY
N
PRECAUTIONS:
1.It can only be used in vertical position.2.It can be used on AC supply.
3.It takes some time to give full light.
4.Wattage of choke and bulb should be same.5.It is available at 80, 125, 250, 400 and 1000watts etc
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QUIZ/ANSWER
Q1. How many tubes in HPMV lamb? Two- inner & outer
Q2. What do you meant by HPMV? High Pressure Mercury Vapour Lamp
Q3. Which gas is filled in inner tube of lamp? Neon or Argon
Q4. What is the pressure of gas? 50-60mm Hg
Q5. Starter is used or not in HPMV lamp circuit? Yes in the form of igniter
Q6. What is the wattage of HPMV lamp? 200-250 watt
Q7. What is the lumen efficiency of HPMV lamp? 30-40 lumens per watt
Q8. How much average life of lamp? 5000 working hours
Q9. Where we use the HPMV lamp? High ways, Airports, Stadium and
Railway yardsQ10. How much time HPMV lamps take to glow? Low pressure
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EXPERIMENT -7
AIM:To study Sodium Vapour Lamp.
THEORY: Sodium vapuor lamp consists of an inner tube (made of special sodium vapor
resistant glass) housing two tungsten electrode, which are connected across an autotransformer.
Inner U tube containing neon gas at a pressure of about 10mm Hg and a small amount of sodium.Inner U tube is well insulated in order to conserve the heat required to vaporize sodium.
CIRCUIT DIAGRAM:
MAIN ELECTRODE
P
INNER TUBE
CHOKE
220V ACSUPPLY
OUTER GLASS
N
HIGH LEAKAGEREACTANCE
AUTOT/FCAPACITOR
WORKINGThe sorting is effected by means of high leakage autotransformer, which delivers an open circuit
voltage of about 450-480 V, which is sufficient to initiate the discharge through the neon gas.After a few minutes, the heat discharge through the neon gas becomes sufficient to vapuorise
sodium; the lamp starts its operation, emitting yellow light. The static capacitor improves the P.Fof the circuit.
CHARACTERISTICS:1. It has a yellow glow having a temperature of 270C2. Its average life span is about 6000working hours.3. Its efficiency is high (about 110 lumen/watt).4. Its takes little time to completely glow to its maximum value and cant is switched ON
immediately after switching it OFF.
5. The lamp should be operated only horizontally, so that hot sodium doesntcollect at one end
PRECAUTIONS:1) Tools should be used carefully.
2) Fitting should be tightly fitted.3) Connection should be tight.
5) Wire should be on the conduit, power gripped properly
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QUIZ/ANSWER
Q1. What do you meant by SVL? Sodium Vapour Lamp
Q2. How many electrodes in SVL. Two Electrodes
Q3. Which gas we used in this type of lamp. Neon gas
Q4. Which material used for electrodes. Tungsten material
Q5. Which colour of light it produces. Light Yellow
Q6. What is the life time of this lamp? 6000 Working hours
Q7. How it hangs vertically or horizontally? Horizontally
Q8. Its power factor is low or high? Low power factor
Q9. What is the operating temp. of this lamp? 270 C
Q10. What is the pressure of gas? 10mm Hg
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EXPERIMENT-8
AIM:To study the single phase induction motor using one phase energy meter, (DPIC) Double
pole iron clad main switch.
APPARATUS REQUIRED: Single phase squirrel caged induction motor, insulated comb,
plier(20cm), screw driver with insulated handle, series testing lamp, voltmeter, connecting wires3/22 PVC wire, wire brush, spanner, etc.
THEORY: The most common type of electric motor is the single- phase type, which finds wide
domestic, commercial and industrial applications. Single phase motors are small- size motorsof fractional kilowatt applications. Single phase motors are small size motors of fractional
kilowatt ratings. Domestic appliances like fans, hair driers, washing machines, vacuum
cleaners, mixers, refrigerators, food processors and other kitchen equipment employ these
motors. These motors also find applications in air- conditioning fans, blowers, office machinery,small power tools, dairy machinery, small farming equipment etc.
Single- phase motors are classified as follows:
1) Induction motors2) Commentator motors3) Synchronous motors
CIRCUIT DIAGRAM:
DPIC1 PHASEENERGY METER
N
1 PHASESUPPLY
M
P
PRECAUTIONS:1) Tools should be used carefully.
2) Fitting should be tightly fitted.3) Connection should be tight.
4) Wire should be on the conduit, power gripped properly
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QUIZ/ANSWER
Q1. In which unit we measure the readings of energy
meter?
KWH
Q2. How much voltage is providing to 1--phase inductor
motor?
AC 220 volt
Q3. At which P.F. of induction motor works? 0.6 Lagging
Q4. What is the name of rotatary part of motor? Rotor
Q5. Which material of coils we used in motor? Copper
Q6. What is DPMS? Double pole main switch
Q7. Which energy meter is used for single-phase induction
motor?
single phase meter
Q8. A.C. supply is given to which part of motor stator or
rotor?
Stator
Q9. What are the main parts of induction motor? Stator, Rotor, Yoke, Field,
Winding
Q10. What is function of Yoke? To protect motor
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EXPERIMENT- 9
AIM:To study three-phase induction motor using three phase energy meter, TPIC (Tripple PoleIron Clad) Switch & DOL (Direct On Line) starter.
APPARATUS REQUIRED:A three-phase induction motor, energy meter, triple polemain switch, direct on line starter.
THEORY:Three-phase induction motor is the most popular type of a.c. motor. It is verycommonly used for industrial drives since it is cheap, robust, efficient and reliable. It has good
speed regulation and high staring torque. It requires little maintenance. It has a reasonable
overload capacity.
A three- phase induction motor essentially consists of two parts: the stator and the rotor. The
stator is the stationary part and the rotor is the rotating part. The stator is built up of high gradealloy steel laminations to reduce eddy current losses. The laminations are slotted laminations
are supported in a stator frame of cast iron or fabricated steel plate. The insulated stator
conductors are placed in these slots. The stator conductors are connected to from a three- phase
winding. The phase winding may be either star or delta connected.
The rotor is also built up of thin laminations of the material as stator. The laminated cylindrical
core is mounted directly on the shaft or a spider carried by the shaft. These laminations areslotted on their outer periphery to receive the rotor conductors. There are two types of induction
motor rotors:
(a)Squirrel cage rotor or simply cage rotor.(b)Phase wound or wound rotor. Motors using this type of rotor are also called slip- ring
motors.
CIRCUIT DIAGRAM:
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PRECAUTIONS:1) Tools should be used carefully.
2) Fitting should be tightly fitted.
3) Connection should be tight.
4) Wire should be on the conduit, power gripped properly
QUIZ/ANSWER
Q1. How much voltage in 3-phase AC supply? 440 Volts A.C.
Q2. What do you meant by DOL? Direct online starter.
Q3. Which type of energy meter we used for 3-phase
supply?
3-0 energy meter
Q4. What do you meant by TPIC switch? Tripple pole iron clad switch
Q5. Where we use squirrel cage type motor? Industrial purpose
Q6. Name two types of I.M.? Squirrel Cage and phase
wound type
Q7. Up to which rating we use DOL starter? Up to 5 HP
Q8. What is the main function of slots? To receive the windings
Varnish & Sleeves
Q9. Name any two laminations? Varnish & Sleeves
Q10. What do you meant by (a) OLRC
(b) NVRC
Over load release coil
No volt release coil
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EXPERIMENT- 10
AIM To study repairing of home appliances such as heater, iron and fans
APPARATUS REQUIRED Electric Heater, fan, electric iron, screw driver, pliers, tester etc.
THEORY Electric Heater consists of cast iron plate housing. The heating element of micron,wire embedded in heat resistant insulated material likes a fire clay element. It takes less time to
get heated up then retain heat for a longer time after switching off the power supply. The usual
rating of hot plate is 1KW or 2 KW.
Heaters are of two types
Table heater: It consists of four parts: base of the heater, the heating plate (made up of cast iron),
circular in shape made up of china clay in which grooves are provided
Room Heater: It consists of stand made up of casted MS steel reflector with metal plate to reflect
more heat and connection of brass and copper.
S.No.
1.
2.
3.
Defects
Short Circuit on Heater
Defects in plug
Change in length
Remedies
Remove Short Circuit
Change the plug
Check the length of wire
Defects and remedies for electric iron(press)
S.No.1.
2.
DefectsIron doesnt work aftersupply is on.
Iron gives shock due to
mica part of the element,
may get short circuited
RemediesThere must be damage ofwire if somewhere circuit
is open
Repair the element to
check the contact strip.
Defect and Remedies for electric fan
S.No.
1.
Defects
Fan dosent work evenafter the supply is on.
Remedies
Check for switch socket,capacitor.
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QUIZ/ANSWERS
Q1. Names some home appliances? Electric Heater, Fan, Iron etc.
Q2. What material we used in heating
element of a heater?
Nicrome
Q3. What is resistance of heating element? .High resistance
Q4. What is the voltage of Hot plate in
heater?
1 to 2 kilo watt
Q5. What are the types of heaters? Table heater and Room heater.
Q6. What is the plating on reflection of
room heater?
Chromium
Q7. What is the rating of ceiling fan? 35 to 80 watt
What is the insulating material in
iron?
Mica
Q9. Which motor is used in fan? 1 Phase induction motor.
Q10. What is the function of thermostat in
iron?
For automatic switching OFFand
ON.