EE ELECTRICAL ENGINEERING DRAWING

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1 EE ELECTRICAL ENGINEERING DRAWING Akhil A. Balakrishnan 1 1 Department of Electrical & Electronics Engineering Jyothi Engineering College, Cheruthuruthy As on January 12, 2014 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

2 We will go through... 1 INTRODUCTION 2 DC ARMATURE WINDING 3 AC MACHINE WINDING Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

3 OBJECTIVES * To make students to be able to plan and draw different views of electrical machines and transformers. * To make the students to draw different types of windings used in electrical machines. * Introduction to AutoCAD in Electrical engineering drawing. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

4 SYLLABUS Module I (12 Hours) DC Windings: Simplex lap and wave dc armature windings. AC Windings: Mush and concentric type single layer three phase ac armature windings. Simplex lap and wave, integral and fractional slot, double layer three phase ac armature windings. Introduction to AutoCad:Developed winding diagrams (Auto Cad not included for Examination). Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

5 Module II (14 Hours) SYLLABUS 1 Sectional plan and elevation of a transformer limb with windings. 2 Sectional plan and elevation of the core assembly of a power transformer. 3 Sectional plan and elevation of a distribution transformer tank with its accessories. 4 Sketches of capacitor and oil filled type transformer bushings. 5 Layout and single line diagram of a distribution transformer. Substation Layouts: 1 Layouts and single line diagrams of outdoor and indoor substations. 2 Layout of a 220KV substation. 3 Layout of a captive power substation. 4 Single line diagram of a distribution centre. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

6 Module III (26 Hours) DC Machines: SYLLABUS 1 Sectional front and side elevation of armature with commutator of a dc machine. 2 Sectional front and side elevation of the yoke and pole assembly with field winding of a dc machine. 3 Sectional front and side elevation of an assembled dc Machine. Alternators: 1 Sectional front and side elevation of a water wheel rotor assembly with winding. 2 Sectional front and side elevation of a salient pole alternator. 3 Sectional front and side elevation of a Turbo alternator. 4 Sketches of the methods of pole fixing and slot details of Turbo and Water wheel alternator. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

7 Text Books REFERENCES 1 Narang K. L., A text book of Electrical Engineering Drawing, Tech India Publications 2 C. R. Dargan, Electrical Drawing and Estimation, New Asian Publishers Reference Books 1 Bhattacharya S. K., Electrical Engineering Drawing, Wiley Eastern. 2 Clayton and Hancock, Performance and design of dc machines, ELBS. 3 Sawhney, Electrical Machine Design, Dhanpath Rai & Sons. 4 Say M.G, Performance and design of AC machines, Pitman, ELBS. 5 A. Nagoorkani, A simplified text in Electrical Machine Design, RBA Publications Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

8 Internal Continuous Assessment (Maximum Marks - 30) 30% - Tests 60% - Assignments such as class work, home work 10% - Regularity in the class University Examination Pattern Q I - 2 questions A and B of 15 marks from Module I with choice to answer any one. Q II - 2 questions A and B of 20 marks from Module II with choice to answer any one. Q III - 2 questions of 35 marks from Module III with choice to answer any one Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

9 DC ARMATURE WINDING Armature Winding: Consists of number of coils connected in series and number of such series circuits are connected in parallel. DC machine armature are double layer windings, which means that each slot has two coil sides. Two types of double layer winding are Simplex Lap winding Finish of a coil is connected to start of next coil. No: of parallel paths = No: of poles Simplex Wave winding Finish of a coil is connected to start of a coil which is lying one pole pitch away from the finish. No: of parallel paths = 2 Ends of the coils are connected to commutators. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

10 DC MACHINE WINDING Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

11 ELEMENTS OF AN ARMATURE WINDING Conductor: Active length of copper or aluminium wire in the slot. Turn: Two conductors connected to an end by an end connector. Two conductors of a turn are placed approximately a pole pitch apart. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

Distance between two coil sides is approximately kept as one pole pitch.

12 ELEMENTS OF AN ARMATURE WINDING Coil Side: Active portions of the conductors in a coil. A coil have two sides. Upper (Top) coil side and Lower (Bottom) coil side. Distance between two coil sides is approximately kept as one pole pitch. Overhang: End portion of the coil connecting the two coil sides. Coil Span: Distance between two coil sides of a coil. Expressed in terms of number of slots or in electrical degrees. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

13 ELEMENTS OF AN ARMATURE WINDING Coil : Several turns connected in series. Principal element of armature winding. Coil with single turn is called single turn coil and with several turns is called multi turn coil. Single Turn Coil Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

Coil with single turn is called single turn coil and with several turns is

14 ELEMENTS OF AN ARMATURE WINDING Coil : Several turns connected in series. Principal element of armature winding. Coil with single turn is called single turn coil and with several turns is called multi turn coil. Two Turn Coil Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

15 ELEMENTS OF AN ARMATURE WINDING Coil : Several turns connected in series. Principal element of armature winding. Coil with single turn is called single turn coil and with several turns is called multi turn coil. Three Turn Coil Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

16 ELEMENTS OF AN ARMATURE WINDING Winding: Several coils connected in series. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

17 ELEMENTS OF AN ARMATURE WINDING Pole Pitch: Peripheral distance between center of two adjacent poles in dc machine. Angle between centers of adjacent poles is 180 (electrical). Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

ELEMENTS OF AN ARMATURE WINDING Full pitched coil: Coil span is equal to pole pitch. Short pitched or chorded coil: Coil span is less than the pole pitch.

18 ELEMENTS OF AN ARMATURE WINDING Full pitched coil: Coil span is equal to pole pitch. Short pitched or chorded coil: Coil span is less than the pole pitch. Single layer winding: Coil sides are arranged in a single layer in a slot. Double layer winding: Coil sides are arranged in two layers in a slot. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

19 IMPORTANT TERMS RELATED TO WINDING Back pitch(y b ): Distance between top and bottom coil sides of a coil measured around the back of armature. Always an odd number. Determines size of the coil (coil span) Equal to coil sides per pole or pole pitch. Front pitch(y f ): Distance between two coil sides connected to the same commutator segment. Winding pitch(y): Distance between the starts of two consecutive coils measured in terms of coil sides. Always an even integer. Y = Y b - Y f for lap winding Y = Y b + Y f for wave winding Commutator pitch(y c ): Distance between two commutator segments to which the ends (start & finish) of a coil are connected. Measured in terms of commutator segments. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

$fraction Back end : 1 + Y b = X 1 Front end : X 1 - Y f = X 2$

20 LAP WINDING Y b = 2C/P ± K Y = Y b - Y f Y = ± 2 (Simplex) Y c = Y/2 = ± 1 (Simplex) Y f = Y b - Y A = P K = integer or fraction Back end : 1 + Y b = X 1 Front end : X 1 - Y f = X 2 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

$fraction Back end : 1 + Y b = X 1 Front end : X 1 + Y f = X 2$

21 WAVE WINDING Y b = 2C/P ± K Y = Y b + Y f Y = (2C ± 2)/(P/2) Y c = Y/2 = (C ± 1)/(P/2) Y f = Y - Y b A = 2 K = integer or fraction Back end : 1 + Y b = X 1 Front end : X 1 + Y f = X 2 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

round the armature, the winding falls in a

Progressive Winding Retrogressive Winding

22 TYPES OF WINDING Progressive Winding: Winding progresses in the direction of the coils are wound. Retrogressive Winding: After passing once round the armature, the winding falls in a slot to the left of its starting point. Progressive Winding Retrogressive Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

23 EQUALISER RING In Lap winding, the EMF s induced in each parallel path may not be exactly equal. It results in internal circulating currents in the armature circuit and in the brushes. Causes : Excessive heating, sparking at the brushes and mechanical vibration. To overcome this, Equaliser rings are provided at the back of the armature. No of equaliser rings, m = Z 2P No of tappings to one equaliser ring = No of pair of poles(p/2) Distance between adjacent tappings = No of coils No of tappings = 2C mp Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

24 DESIGN OF WINDING No of slots = S No: of conductors or coil sides = Z No: of coils,c = Z/2 No of commutator segments = No: of coils No: of poles = P No: of parallel paths = No of brushes= A Coil Span = No: of slots per poles Coil sides per slot = Z S Coil sides per pole = Z P Back pitch = Y b Front pitch = Y f Winding pitch = Y Commutator pitch = Y c Y c, Y b and Y f will be always an odd integer Y is always an even integer Progressive Winding + sign, Retrogressive Winding - sign Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

25 DESIGN OF WINDING Bottom coil side of current coil = Top coil side of current coil + Back Pitch (Both Lap & Wave) Top coil side of next coil = Bottom coil side of current coil - Front Pitch (Lap) Top coil side of next coil = Bottom coil side of current coil + Front Pitch (Wave) Winding Calculations Back Connections Front Connections Winding Table Ring Diagram Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

26 Example 1 Design and draw the developed winding diagram for a 4 pole, 8 slots, double layer simplex lap winding for a DC generator. Show the connections to equalizer rings. P = 4, S = 8 C = 8 Coil sides per slot = 2 Z = 16 Coil sides per pole = Z P = 16 4 = 4 Y b = 2C 2 8 P ±K = 4 ±K = 5(Progressive) or 3(Retrogressive) Y c = ±1(Simplex) ; Y = ±2 (Yc = Y/2) Y f = Y b - Y = 5-2 = 3 No of equalizer rings, m = Z 2P or C P = 8 4 = 2 No of tappings to one equalizer rings = P 2 = 4 2 = 2 Distance between adjacent tappings = 2C mp = = 2 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

27 Winding Calculations 1+5=6 6-3=3 3+5=8 8-3=5 5+5= =7 7+5= =9 9+5= = = = =18(2) 18-3= =20(4) 4-3=1 Back Connections (2) 15 20(4) Winding Table (2) 15 20(4) 1 Ring Diagram Front Connections Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

28 Lap Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

29 Example 2 Design and draw the developed winding diagram for a 4 pole, 13 slots, double layer simplex wave winding with 13 commutator segments. P = 4, S = 13 C = 13 Coil sides per slot = 2 Z = 26 Coil sides per pole = Z P = 26 4 = 6.5 Coil sides per pole should be an integer, Coils sides per pole = 6 Y b = 2C 2 13 P ±K = 4 ±K = 7(Progressive) or 5(Retrogressive) Y = 2C±2 P/2 = 2 13±2 4/2 = 14, Y c should be always an odd integer Y f = Y - Y b = 14-7 = 7 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

30 Winding Calculations 1+7=8 8+7= = =29(3) 3+7= = = =31(5) 5+7= = = =33(7) 7+7= = =28(2) 2+7=9 9+7= = =30(4) 4+7= = = =32(6) 6+7= = =27(1) Winding Table Back Connections (2) (4) (6) Front Connections (3) (5) (7) (1) Ring Diagram (3) (5) (7) (2) (4) (6) (1) Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

31 Wave Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

32 Exercises 1 Design and draw the developed winding diagram for a 4 pole, 12 slots, double layer simplex lap winding for a DC generator with 12 commutator segments. 2 Design and draw the developed winding diagram for a 4 pole simplex wave winding having 25 slots, 25 coils and 25 commutator segments. 3 Design and draw the developed winding diagram for a 4 pole, 24 slots, double layer simplex lap winding for a DC generator with 24 commutator segments. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

33 AC MACHINE WINDING Identical to DC machine winding In an AC winding, the commutator & its connection are not required. AC machine winding may be open, in the case of star windings and closed in the case of delta windings Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

34 CLASSIFICATION Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

35 IMPORTANT TERMS USED IN WINDING Slots per pole per phase(spp): To divide the slots into different phase-groups. spp is an integer : Integral Slot winding. spp is a fraction : Fractional Slot winding. Coil Pitch or coil span: Distance between two active coil sides of a coil in terms of slots. coil pitch = pole pitch Full pitched winding. coil span < pole pitch Short pitched winding. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

36 SINGLE LAYER WINDING Three phase windings are of two types: Single Layer winding Rarely Used Double Layer winding. Disadvantages of single layer windings are: Inconvenience in arrangement of the overhang. High cost in production. Chording & use of fractional spp is not possible. Single layer windings have one coil side per slot A coil completely occupies 2 slots Classified into: Mush Type. Concentric Type. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

37 MUSH WINDING All coils have same span One coil side is longer than the other Long and short coil side occupy alternate slots Coil span should be odd Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

38 Example 3 Draw a mush winding diagram for a 4 pole, 36 slots,three phase armature. P = 4, S = 36 Slots per pole per phase(spp) = = 3 One pole phase group consists of 3 slots Coil sides are arranged as alternate long and short coil sides. Coil span = pole pitch = 36 4 = 9 slots Angle between two consecutive slots = = 20 electrical Start of phase R is assumed to be in slot no: 1 Start of Y phase lies 120 electrical apart from Phase R Start of B phase lies again 120 electrical apart from Phase Y. No: of coils corresponding to 120 electrical= = 6 slots Start of coil side of phase Y lies in slot no: 7 and Start of coil side of phase B lies in slot no: 13 Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

39 Mush Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

40 CONCENTRIC WINDING Made up of concentric coils of different pitches, for each pair of poles Divided into two main groups: Unbifurcated winding. A pair of adjacent pole phase groups form a concentric coil. Bifurcated winding. Each pole phase groups is split into two sets of concentric coil, sharing its return coil sides with another such group. Overhang should be accommodated in separate planes Pole pairs is even Can be accommodated in 2 planes. Pole pairs is a multiple of 3 Can be accommodated in 3 planes. If overhang has to be accommodated in 2 planes, a cranked coil group results. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

41 Example 4 Draw a single layer concentric unbifurcated winding diagram with two plane overhang, for a three-phase, 48 slots, 8 pole, AC armature. P = 8, S = 48 Slots per pole per phase(spp) = = 2 One pole phase group consists of 2 slots Coil span = pole pitch = 48 8 = 6 slots Angle between two consecutive slots = = 30 electrical No: of coils corresponding to 120 electrical= = 4 slots One coil group is placed in four slots, one pole pitch apart. No: of coil groups = 48 4 = 12 No: of pole pairs is even, hence overhang is arranged in two planes Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

42 Unbifurcated Concentric Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

43 Example 5 Develop a single layer winding concentric unbifurcated type winding diagram with two plane overhang for a three phase, 36 slots, 6 pole armature. P = 6, S = 36 Slots per pole per phase(spp) = = 2 One pole phase group consists of 2 slots Two coil sides are split into 2 sets of concentric coils sharing its return coil side with another group. Coil span = pole pitch = 36 6 = 6 slots Angle between two consecutive slots = = 30 electrical No: of coils corresponding to 120 electrical= = 4 slots No: of coil groups = 36 4 = 9, No: of pole pairs = 3 Overhang can be accommodated in 3 planes If the overhang is to be accommodated in 2 planes, we get cranked coil groups. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

44 Unbifurcated Concentric Winding with Cranked Coil Group Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

45 Example 6 For a three phase AC machine, the armature is having 24 slots. A single layer concentric bifurcated winding for four poles is to be made. Draw the developed winding diagram with the overhang in three planes. P = 4, S = 24 Slots per pole per phase(spp) = = 2 One pole phase group consists of 2 slots Two coil sides are split into 2 sets of concentric coils sharing its return coil side with another group. Coil span = pole pitch = 24 4 = 6 slots Angle between two consecutive slots = = 30 electrical No: of coils corresponding to 120 electrical= = 4 slots One coil group is placed in two slots. No: of coil groups = 24 2 = 12. Overhang is accommodated in 3 planes. Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

46 Bifurcated Concentric Winding Akhil A. Balakrishnan (JECC) Lecture Notes As on January 12, / 44

EE ELECTRICAL ENGINEERING DRAWING

EE ELECTRICAL ENGINEERING DRAWING EE09 605 ELECTRICAL ENGINEERING DRAWING Akhil A. Balakrishnan 1 1 Department of Electrical & Electronics Engineering Jyothi Engineering College, Cheruthuruthy As on February 24, 2014 Akhil A. Balakrishnan