practical:-8 electrical workshop diploma 2nd semester as per GTU

Electrical Workshop

PRACTICAL-8

AIM: IDENTIFY DIFFERENT TYPES OF LIGHT SOURCES.

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-9 electrical workshop diploma 2nd semester as per GTU

Electrical workshop

PRACTICAL:-9

AIM: - IDENTIFY DIFFERENT TYPES OF SWITCHES USED FOR DIFFERENT APPLICATION.

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-10 electrical workshop diploma 2nd semester as per GTU

Electrical Workshop

PRACTICAL -10

AIM:-  IDENTIFY AND SPECIFY DIFFERENT TYPES OF SOCKET AND PLUGS USED FOR DIFFERENT CURRENT AND VOLTAGE RATINGS.

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-5 electrical workshop diploma 2nd semester as per GTU

Electrical Workshop 

PRACTICAL - 5

AIM: - CONNECT DIFFERENT DOMESTIC APPLIANCES TO POWER SUPPLY.

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-4 electrical workshop diploma 2nd semester as per GTU

Electrical workshop:practical :-4

AIM:-USE OF COMMON TESTING INSTRUMENTS USED IN ELECTRICAL WORKSHOPS

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-2 electrical workshop diploma 2nd semester as per GTU

PRACTICAL :- 2 

ELECTRICAL WORKSHOP

AIM: - DRAW AND VARIFY DIFFERENTS TYPES OF ELECTRICAL SYMBOLS.  

here is the downloadable file for that practical 

please click on the below link:

DOWNLOAD FILE

Share

Blogger Widget

practical:-7 electrical workshop diploma 2nd semester as per GTU

PRACTICAL NO:-7

AIM: IDENTIFY AND SPECIFY DIFFERENT TYPES OF WIRES, CABLES, CABLE JOINTS USED FOR DIFFERENT CURRENT AND VOLTAGE RATINGS.

THEORY:

Wires are used for passage of electric current in many ways from generating power plant to various distribution levels like (1) In overhead Transmission and distribution lines,(2) In giving service connection to various consumers,(3) In winding coils of electrical machines,(4) In house and industrial wiring,(5) In underground cables etc.For conduction of small current, single standard insulated copper conductors are used. As per the current rating, the conductors have specific diameter or cross-sectional area and level of insulation depends upon voltage rating. Following various types of wires and cables are used in domestic and industrial wiring:

1)   V.I.R.( Vulcanized India Rubber) wire.

 2)   C.T.S. or T.R.S. (Cab Tyre Sheathed or Tough Rubber Sheathed) wire.

3)   Weather proof wire.

4)   L.C.(Lead Covered) wire.

5)   MICC (Mineral insulated copper covered) wire.

6)   PVC  (Poly Vinyl Chloride) wire.

7)   Flexible wire.

1) VIR (Vulcanized India rubber) wire:

Figure 1 Single Braided VIR Wire    

                                                   

 FIGURE 2 Double Braided VIR Wire

                        In this type of wires conductors are made up of aluminum or copper. A layer of vulcanized rubber is provided over it. There may one or two layers. Over this a cotton tape is wound and braiding of impregnated cotton is wound over it. 

                   Single braided wire and double braided wire is shown in figure. These types of wires can bear little mechanical stress. Due to the effect of water, moisture etc. its insulation properties are reduced. Chemicals also effect the insulation and it may be cut due to the sharp tools etc. Due to excessive heat the rubber may melt.

2) CTS or TRS (Cab tire Sheath or tough rubber sheath) wire:

                        In this type of wire layer of strong and durable rubber is provided over the conductor. Its mechanical strength is more than that of the VIR wire. Effect of heat, moisture and water is less in it. This type of wire is available in varieties of single core, twin cores and three cores. It is used in house wiring and industrial wiring. Single core and twin core wire is shown in figure.

               

FIGURE 3 Single Core TRS Wire 

                                                         FIGURE 4 Twin Core TRS Wire

 (3) Weather proof wire:

                        On this type of wire there is no effect of atmosphere. A layer of rubber is provided on copper conductor. Braiding of cotton is provided on this. It is made waterproof by dipping it into waterproof compound. This type of wire is available in single core or double core types. Outer sheath is inflammable so it is ot used in casing-capping type wiring and the places where there are inflammable materials. It is useful in service connections. Its use is nowadays has become limited.

(4) LC (Lead Covered) wire:

                        In this type of wire coating of insulated rubber is provided on the conductor. A tube made of lead is kept over it. Due to there is no effect of moisture on the rubber. So it is used in the place where there is presence of moisture. As Lead is soft. It is easily affected by mechanical stresses. So care has to be taken while using it. This wire can be used directly on wooden batten.

(5) MICC (Mineral insulated copper covered) wire:

                        In this type of wire coating of magnesium oxide is provided as insulation on the copper conductor. Over this copper sheath is provided. When this wire has to be used in moist atmosphere, a serving made of PVC is provided over this. This wire is less affected by temperature. This type of wire is used in wiring in mines, factories, refineries, furnace, boilers, rolling mills etc.

FIGURE 5 MICC Wire

(6)PVC (Poly Vinyl Chloride) Wire:

                        In this type of wire insulation made of poly vinyl chloride is provided over copper or aluminum conductor. PVC wires are widely used and use of paper and rubber insulated wires is reduced. This type of wire is manufactured for voltage rating of 11 KV. It is available in single PVC and double PVC Types. This type of wire is also available in twin core and three core circular and two core flat types.

FIGURE 6 Single PVC Wire

              

FIGURE 7 Double PVC Wire 

                                  

(7)Flexible wire:

FIGURE 8 Flexible Wire

In this type of wire instead of using thick conductor many thin copper conductors of 36 gauges are used. This is called stranding. These wires are available in the size of 14/36, 23/36, 40/36 etc. These strands are twisted and PVC insulation is provided over it.

Such two wires of different colors of insulation are twisted together and coil is prepared. As the flexible wire is used instead of thick wire, the wire can be bent in any direction. This type of wire is used in giving connections to table lamp, fan, tube light etc.

CABLES: Cables are classified according to basis of construction.

(1)Low tension cable

(2) Belted cable

(3) Screened or H type cable

(4) SL type cable

(5) HSL type cable

(6)Super tension Cable

(1) Low Tension cable:

                        Vulcanized India rubber (VIR) cables are manufactured for the voltage ratings of 250/440V and 650/1100V. Aluminium or copper core is used. Insulation of VIR is provided on the core. Braiding of cotton, tough rubber sheath or metal sheath is used.

Figure 9 Construction of Single Core PVC Cable      

Figure 10 screened or H type cable

 PVC cables are becoming popular. In this, there is insulation of PVC over the copper or aluminium core. Sheath of PVC is provided over the insulation. There is armoring of steel tape or steel wire over the sheath. There is covering of PVC over the armoring which works as the serving.

(2) Screened or H type Cable:

                       Figure 10 screened or H type cable

This type of cable was developed by M Hochstadter so this type of cable is known as the H type Cable. Figure shows the telescopic view of this type of cable. Each core is insulated and then a screen of metalized paper is wound round it. So this type of cable is called the screened type cable. Metalized screen is perforated so the process of impregnation can be done easily.

(3) Belted cables:

Figure 11 Belted Cables

                        Belted cables are used for the medium voltages. Construction is similar to the LT Cables. There is paper insulation surrounding the core, which is called the belt. Figure (a) shows two-core shaped cable. Figure (b) shows three core shaped cable. Figure (c) shows the round core three-core cable while figure (d) shows four-core shaped cable.

(4) SL cable:

                       

Figure 12 SL Cable   

 SL cable means separate lead sheathed cable. In this Type of cable, there is paper insulation surrounding the core. There is Separate lead sheath over each core. So all the three cores work as separate cable and the dielectric stress become radial. No overall lead sheath is used surrounding the three cores. Bedding, armoring and serving are provided like other cables.

(5) HSL Cable:

           Figure 13 HSL Cable

This type of cable is the combination of H type and SL type cables. Paper insulation is provided over each core. Metalized paper is wound over the insulation and lead sheath is provided over this. Filler space is filled with copper woven fiber material. Bedding, armoring and serving are provided as usual.

(6) Super Tension Cable:

In this type of cable no additional arrangement is made to prevent the formation of voids. If the cables are to be used for 132 KV and 220 KV, arrangement has to be made to prevent formation of voids and to increase the dielectric strength. This can be achieved by two ways.

(1)By using the oil filled cables

(2) By using the gas filled cables.

Figure 14 Single Core Cable with Oil Channel in Conductor     

Figure 15 single core oil filled cable with oil channel in the sheath

Figure 16 Three Core Cable with Oil Channel in the Filler Space

CONCLUSION:

DOWNLOAD FILE

Share

Blogger Widget

practical:-6 electrical workshop diploma 2nd semester as per GTU

PRACTICAL:-6

AIM: TO IDENTIFY DIFFERENT TYPES OF DOMESTIC WIRING.

THEORY:

There are four types of wiring used in domestic wiring.

(1)Cleat wiring

(2) Batten Wiring

(3) Casing-Capping Wiring

(4) Conduit wiring

DOMESTIC WIRING:

(1)CLEAT WIRING:

                   Cleat is in two parts. Two or three grooves are provided in the bottom part. Cleats are made from China Clay material. There is one hole in each part to allow the screw to pass through. Wires are placed in grooves and after putting the top cleat, it is fitted on wall. Distance of half a metre is kept between the adjacent cleats. Vulcanized India rubber (VIR) wire is used in cleat wiring. This type of wiring is used only for temporary use. It cannot be used for permanent use. Wires are in the open atmosphere so there is effect of dust, moisture, fumes etc.

(2)BATTEN WIRING:

                   In this type of wiring a long wooden batten is fitted on the wall with the help of screws. Small clips are fitted on the batten with the help of small nails. Wires are fitted on the batten with the help of clips. The type of wiring depends upon the type of wire used.

(a)PVC Wiring:

                   In this type of wiring PVC wires are used. Single PVC or double PVC wires are used. PVC wires on batten wiring are popular for house wiring.

(b) TRS/CTS wiring:

                   In this type of wiring Tough Rubber Sheath (TRS) or Cab Tire Sheath (CTS) wires are employed. It is fitted on the batten with help of clips. As special type of rubber is used instead of ordinary rubber there is no effect of moisture. This type of wiring is costlier than PVC wiring.

(c) Lead Sheath wiring:

                   In this type of wiring lead sheath wire is used. So there is no effect of moisture, fumes etc. Moreover mechanical protection is available. It is necessary to earth the lead sheath.

(3) CASING-CAPPING WIRING:

          There are two types of casing- capping wiring: (A)Wood casing-capping wiring and (B) PVC Casing-capping wiring

(a) Wood casing-capping wiring:

          In this type of wiring there is long strip of wood with two grooves along the length. This is called casing. Casing is fitted on the wall with the help of screws. VIR wires are kept in the grooves. Casing is covered by thin strip of wood. It is known as capping. In this type wiring there is protection against moisture, dust, mechanical damage etc. but there is no protection against fire.

(b) PVC Casing-Capping wiring:

          Recently PVC Casing-capping type wiring is becoming popular. It is called PVC Channel wiring also. PVC Channel is in two parts. One is the base and the other is the top. Base is of C section. Holes are drilled at regular intervals in the base for fixing. Channel is fixed on the wall or ceiling with the help of screws passing through these holes. There is snap on cover which is fixed on channel by pressing it. No nail or screw is needed for this. Channels are of two types: continuously slotted type and rigid type.

          In Continuously slotted type channel, slots are given on both the side walls. Wires are taken in and out of the channel through these slots. In rigid type channel no slots are provided.

          This type of wiring is light in weight and can be easily installed. Wires are not to be pulled as in conduit wiring. Its cost is less and fault can be detected easily, as the channel can be opened easily. In addition to this the appearance of wiring is also good.

(4) CONDUIT WIRING:

                   In this type of wiring long thin hollow tube of steel or PVC called Conduit is used. Conduit is fixed on wall with the help of saddle. Inspection boxes are provided at certain intervals.

                   PVC or VIR wire is kept in conduit. In conduit wiring there is protection against moisture, dust, mechanical damage, fire etc. however in PVC Conduit wiring there is no protection against fire.

Types of conduit wiring:

                   Conduit wiring can be done by two ways: (i) surface conduit wiring and (ii) concealed conduit wiring, in surface conduit wiring conduit is fixed on the surface of the wall or ceiling with the help of saddle. While in concealed conduit wiring Conduit is kept under the ceiling or wall. So conduit is not visible. So the appearance of the room is not spoiled due to the wiring. It is necessary first to decide precisely the locations of points because it is very difficult and costly to alter the locations afterwards. Surface conduit wiring are shown in figure.

TYPES OF CONDUIT:

          For wiring the following type of conduits are used:

(1)Rigid steel conduit

(2) Rigid non-metallic conduit

(3) Flexible steel conduit

(4) Flexible non-metallic conduit

1) RIGID STEEL CONDUIT:

This type of conduit is made up of steel. There are two types:

(a)Heavy gauge screw type

          Heavy gauge conduit is either solid drawn or welded type. Solid drawn conduit is costly. It is used only for gas proof or explosion proof wiring installations. While seam welded type heavy guage conduit is used for domestic, commercial and industrial wiring installations.

(b) Light gauge.

          Light gauge conduit is manufactured by bending the thin sheet of steel. The vertical joint is sometime open. So it is not useful for weather proof wiring installations. This type of conduit cannot be used as earth conductor, but separate earth wire should be run.

2) NON-METALLIC CONDUIT:

          Non-metallic conduit is made of fiber asbestos, PVC, high density polythene (HDP) or poly vinyl (PV). PVC conduits are widely used as it gives protection against moisture and chemical surroundings. Its weight is less and is less costly and can be installed easily. This type of conduit can be buried in wall or ceiling.

3) FLEXIBLE CONDUIT:

          Where there are vibrations of the machine and where there is no possibility of installing rigid conduit. This type of conduit is used. Earthing wire has to be run.

CONCLUSION

DOWNLOAD FILE

Share

Blogger Widget