Unit 1 BEEE PDF

Matoshri College of Engineering and Research Centre, Nashik Department of Engineering Sciences Course Name: Basics of Electrical and Electronics Engineering Course Code: 24U0104 An Autonomous Institute  Teaching and Marking Scheme...

Matoshri College of Engineering and Research Centre, Nashik Department of Engineering Sciences Course Name: Basics of Electrical and Electronics Engineering Course Code: 24U0104 An Autonomous Institute  Teaching and Marking Scheme Examination Head: TH Teaching Scheme Credit Examination Scheme & Marks ISE ▪ CAT_1: 20 Marks TH: 03 Hours/Week 03 ▪ CAT_2: 20 Marks ESE : 60 Marks  Course Outcomes Blooms CO CO Statement Taxonomy No. Level Understand the use of wires, cables, protective devices, electrical CO1 2 safety measures and concept of batteries, inverter and UPS. Understand and Demonstrate the digital circuit using gates, CO2 1,2,3 Flip-Flop, Shift Registers and Counters. Recognize and Understand the efficiency and regulation of a CO3 1,2,3 single-phase Transformers, select motors for particular applications. Understand various communication systems, cellular concepts and CO4 1,2 GSM systems. Remember and Understand working of various Electrical, Electronic CO5 3 Instruments, select sensors for particular application Matoshri College of Engineering and Research Centre, Nashik Course Name: Basics of Electrical and Electronics Engineering Course Code: 24U0104 Class: FE (Engineering Sciences) (Common for all branches) Unit No. 1: Electrical Wiring and Safety  Contents Electrical Wiring: Difference between wires and cables, Parts of cable, Types of cables, conductor sizes and current rating of cable, Types of wires, conductor sizes and current rating of wires. Electrical safety: Electrical safety measures, Earthing and its importance, Types of earthing. Fuses: Types, Selection, Advantages, Disadvantages and Applications, Miniature Circuit Breaker (MCB), Difference between Fuse and MCB, Earth Leakage Circuit Breaker (ELCB), Lightning protection. Batteries: Construction, Working principle, Applications, Charging and discharging of Lithium ion and Lead acid batteries, Concept of depth of discharging, Series Parallel Connection of batteries, battery selection, Inverter, UPS. Matoshri College of Engineering and Research Centre, Nashik Course Name: Basics of Electrical and Electronics Engineering Course Code: 24U0104 Class: FE (Engineering Sciences) (Common for all branches) Part A: Electrical Wiring  WIRES Any conductor which is composed of a conducting material and is uniform in diameter and circular in cross section is called a wire. Wire is one type of electrical conductor generally used to carry electricity. It allowing the current to flow from one end to another end. There are two types of wires 1) Solid wires and 2) Stranded wires Solid wire is a long length of single conductor while stranded wires comprises of multiple thin stranded of conductor twisted together. Commonly used in household electrical system, simple connections or within small electronic devices.  CABLES A length of single insulated conductor or two or more such conductors each provided with its own insulation which laid up together is called as cable. They are designed to transmit power, data or signals more efficiently over longer distances or in the complex system. It consist of multiple wires or conductors bundled together each potentially having its own insulation layer and are often covered with with an additional outer protective layer. It also include shielding to protect against electromagnetic interference (EMI) or to contain signals. Used in more complex or demanding situations like power distribution, data transmission and for networking. Parts of the Cables: A cable consists of the following three main parts, Conductors Insulation Covering Protective Covering ❖Metallic Sheath ❖Bedding ❖Armouring ❖Serving Core(Conductor): The Core is a conducting parts of a cable. This core may be one or more than one depending upon the type of service. A three core cable is shown in fig. The conductors are made of tinned copper or aluminum. The thickness of the core depends upon the rating of current and voltage rating. Insulation: Insulation of cable is a layer of insulating materials which is provided over the conductor. The thickness of insulation depends upon the voltage to be withstood by the cable. The insulation of cable must be strong enough to because of leakage current will start giving electrical shocks and can cause fire. Metallic sheath: A metallic sheath of lead or aluminum is provided over the insulation of cable for protecting the cable from moisture, gases or other liquids (like) acids or alkalis in the soil and atmosphere. Bedding : Bedding is a layer in between metallic sheath and armoring. It consists of fibrous materials like jute or hessian tape. It protects the metallic sheath against corrosion and from mechanical injury due to armoring. Armouring: Armoring is provided over the bedding which consists of one or two layers of galvanized steel wire or steel tape. It protects the core from mechanical injury which laying and during the handling. Serving: A layer of fibrous materials is provided over the armouring to protect the armouring from atmospheric conditions. This layer is known as serving of the cable.  Types of Cables The following cables are used for different types of wiring installation 1.Vulcanized Insulation Rubber (VIR) cable 2.Cab Tyre Sheathed (CTS) Cable 3.Polyvinyl Chloride (PVC) Cable 4.Lead Sheathed Cable 5.Weather Proof Cables 6.Tropodure Cable 7.Flexible Cable Vulcanized Insulation Rubber (VIR) Cable: This cable is also known as V.I.R. cable. In this cable tinned copper or aluminium conductors are used. The conductor is insulated with vulcanized rubber. It is then covered with cotton tape and finally finished with compounded braiding. This cable is available in single core only. It is used in casing capping, conduits are temporary light wirings. Cab Tyre Sheathed (C.T.S.) Cable: This cable is also known as T.R.S. (tough rubber sheathed) cable. The conductors are insulated with vulcanized rubber insulation but the protective covering used on the cable is a sheath of tough rubber compound. The cables are resistant to moisture and are used at damp places. These cables are available in 1, 2, 3 and 2 core with earth continuity conductors. Polyvinyl Chloride (P.V.C.) Cable: The conductor of this cable is covered with polyvinyl chloride insulation and serves both the purposes of insulation covering and mechanical protective covering. It is a very hard and tough synthetic chemical substance and resists the action of acid alkali and atmospheric variations in temperature. Its use is restricted where there is a possibility of the temperature being very high as it softens (being thermoplastic) and at low temperatures where it becomes brittle. This cable has now replaced the C.T.S. cable. Lead Sheathed Cable: These cables are also insulated with vulcanized rubber insulation. However, the protective covering employed on these cables is the metallic lead sheathing. These cables are manufactured in 1, 2, 3 and 2 core with earth continuity conductors. As these cables are very costly, they are not used for house wiring. However, they are used in open places for short-distance overhead lines, service lines and also for indoor wiring in chemical plants. Weather-proof Cable: The conductors of weather-proof cables are also insulated with vulcanised rubber which is covered with empire tape to make it non-absorptive of moisture. It is then again covered with a braiding of cotton thread. To make the cable insulation more effective against the atmospheric moisture, this braiding is dipped in a waterproof compound. Tropodure Cable: Tropodure is the trademark for thermoplastic compounds on a polyvinyl chloride basis. This insulation is harder than the P.V.C. insulation. It is employed on conductors both as an insulation and as a sheathing. These cables are suitable for lighting, power installation as well as railway signalling. They can also be laid in water and used as submarine cables or buried directly in the ground. They are also available in aluminium and copper conductors of 1, 2, 3, 31/2 and 4 cores. Flexible Cord: These flexible cords consists of two separately insulated flexible stranded conductors of a thin copper conductor of 36 S.W.G. The insulation used on these wires is also vulcanized rubber but the protective covering used is either silk or cotton. These cords are used for domestic, portable appliances, such as table fans, table lamps, electric irons, heaters, refrigerators, etc. They must be durable and very flexible. Flexibility is required because of the handling of portable equipment and to prevent the wires from breaking. Conductor Sizes and Current Rating of Cable: Cables Cross Sectional Typical Current rating Area (mm2) (Amp) 1.5 7.9-15.9 2.5 15.9-22 4 22-30 6 30-39  Selection of Cable for Wiring Installation The following points should be considered while selecting a cable for installation 1) Effect of atmosphere: The insulation of cable should not be affected by surrounding atmosphere condition for ex. a weather proof cable is used for open places, a tropodure cable should be used for oil mills & lead covered cable is used in chemical plants as acid fumes can destoy the insulation of other cable. 2) Maximum Voltage of the Circuit: The grading of the cable should be equal to the maximum working voltage of the circuit. 3)Full Load current: The current rating of the cable must be such that should pass the rated current.  Types of Wires The wires used for general electrical purposes can be divided into the following: 1.Rubber covered, taped, braided and compounded wire 2.Lead alloy sheathed 3.Tough rubber sheathed (Cab Tyre sheathed) 4.PVC Wire 5.Weather proof wires 6.Flexible wires 1) Rubber covered, taped, braided and compounded wire: It is also called as VIR wires. It consists of a tinned copper or aluminium conductor covered with a layer of rubber insulation. (Tinning of conductor prevents sticking of rubber to conductor.) Over this rubber insulation is put up a cotton protective braid which is usually saturated with flame retarding and moisture-resistant compound. Finally it is finished with a wax for cleanliness and for helping the pulling action of it into the conduits. it is suitable for low and medium voltage only. 2) Lead alloy sheathed wire: Such types are recommended where the climatic condition is not dry, but has a little bit of the moisture. These wires provides little mechanical protection to the wires. The more stronger and mechanically strong wires are used for laying uder the ground. 3) Tough rubber sheathed Wire: This type of wire is modification of VIR wire. It consist of ordinary rubber coated conductors with an additional sheath of tough rubber. This layer provides better protection against moisture and wear and tear. These wires are generally available in single conductor, two conductor or three conductors. 4) Poly Vinyl Chloride (PVC) Wires: This is most commonly used wire for wiring purpose. Conductor is insulated by poly vinyl chlorides. PVC has some properties such as Moisture proof, tough, durable and chemically inert, but it softens at high temperatures therefore not suitable for connection to heating appliances. 5) Weatherproof Wires: These types of wires are used outdoor i.e. providing a service connection from overhead line to building etc. In this type of wire the conductor is not tinned and conductor is covered with three braids of fibrous yam and saturated with water proof compound. 6) Flexible Wires :- These wires consists of number of strands instead of a single conductor (Strand is a very thin conductor) The conductor is insulated with P.V.C material. These wires are very useful for household portable appliances where flexibility of wire is more important. Typical specifications 55/0.1mm (55 stands of 0.1mm diameter), maximum current, 6 A, used for household purposes. The wires used for household appliances such as heaters, irons, refrigerators, lamps ete must be durable and very flexible Gauge No. and Wires Diameter: The smallest wire gauge is of no 40 having a diameter of 0.0048 inch while the larges no. of wire is 0,000,000 (named as seven zero) or written as 7/0 having a diameter of 0.5. Higher the no. of wire gauge, the smallest is the diameter. Gauge Diameter No. Inch mm 7/0 0.500 12.7000 4/0 0.400 10.1600 0 0.324 8.2276 1 0.300 7.6200 39 0.0052 0.1321 40 0.0048 0.1219 Wire Gauge Meter Matoshri College of Engineering and Research Centre, Nashik Course Name: Basics of Electrical and Electronics Engineering Course Code: 24U0104 Class: FE (Engineering Sciences) (Common for all branches) Part B: Electrical Safety  Electrical Safety Recognizing hazards associated with use of electrical energy and taking precautions so that hazards do not cause injury or death. While working on electrical installation it is necessary to observe and follow safety guidelines and use of appropriate personnel protective equipments (PPE). following safety guidelines should always be observed while working on electrical installation: ❖ Do not forget to put off main switch in case of person is electrocuted. ❖ Do not attempt to disengage a person in contact with live apparatus, which you you cannot switch off immediately. Insulate yourself from the earth by Standing on a rubber mat or dry board of wood before attempting to get him clear. Even then do not touch this body, push him clear with piece of dry wood. ❖ Do not forget to put off main switch and take away the fuse carrier along while working on Electrical installation. Put a Caution noticed (Tag) on or near the main switch inscribing "danger, men at work.” ❖ Do not discontinue artificial respiration until recovery or death is Certified by doctor. ❖ Do not forget to put on your safety belt before starting working on pole. If used, it must a ladder is used, it must be held is used by another man to avoid Slipping. ❖ Do not have any sharp tool protruding from the pocket when working on a high Voltage overhead line. Always keep one hand in pocket.  EARTHING WHAT IS EARTHING? The process of connecting metallic bodies of all the electrical apparatus and equipments to earth by wire having negligible resistance is called earthing. OR Earthing means connecting neutral point of supply system or non-current carrying parts of electrical apparatus to the general mass of earth in such a manner that all times an immediate discharge of electrical energy takes place without danger.  Objectives of Earthing Provide an alternative path for fault current to flow so that it will not endanger the user Maintain the voltage at any part of an electrical system at a known value so as to prevent overcurrent or excessive voltage on the appliances or equipment. Good Earthing means must have low impedance enough to ensure sufficient current can flow through safety devices so that it disconnects the supply (