Basic Electrical Engineering_P. S. Dhogal

8/10/2019 Basic Electrical Engineering_P. S. Dhogal

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Scilab Textbook Companion for

Basic Electrical Engineering

by P. S. Dhogal1

Created byNishtha Rani

B.TechElectrical Engineering

UKTUCollege Teacher

Vinesh SainiCross-Checked by

Lavitha Pereira and Mukul Kulkarni

January 28, 2014

1Funded by a grant from the National Mission on Education through ICT,http://spoken-tutorial.org/NMEICT-Intro. This Textbook Companion and Scilabcodes written in it can be downloaded from the Textbook Companion Projectsection at the website http://scilab.in


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Book Description

Title: Basic Electrical Engineering

Author: P. S. Dhogal

Publisher: Tata McGraw-Hill Publishing, New Delhi

Edition: 1

Year: 2005

ISBN: 0-07-45186-1

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Scilab numbering policy used in this document and the relation to theabove book.

Exa Example (Solved example)

Eqn Equation (Particular equation of the above book)

AP Appendix to Example(Scilab Code that is an Appednix to a particularExample of the above book)

For example, Exa 3.51 means solved example 3.51 of this book. Sec 2.3 meansa scilab code whose theory is explained in Section 2.3 of the book.

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Contents

List of Scilab Codes 4

3 electricity and its fundamental law 8

4 Work power and energy 17

5 effects of electric current 30

6 magnetism and electromagnetism 33

7 DC generators 35

8 DC motors 50

9 cells and batteries 64

11 single phase AC circuits 74

12 polyphase system 92

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List of Scilab Codes

Exa 3.1 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 8Exa 3.2 voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 8Exa 3.3 specific resistance . . . . . . . . . . . . . . . . . . . . 9Exa 3.4 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 9Exa 3.5.a total resistance . . . . . . . . . . . . . . . . . . . . . . 10Exa 3.5.b current flowing . . . . . . . . . . . . . . . . . . . . . . 10Exa 3.6 voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 11Exa 3.7 total resistance . . . . . . . . . . . . . . . . . . . . . . 11Exa 3.8 voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 12Exa 3.9 effective resistance and current . . . . . . . . . . . . . 12Exa 3.10 current . . . . . . . . . . . . . . . . . . . . . . . . . . 13Exa 3.11.a unknow resistance . . . . . . . . . . . . . . . . . . . . 14Exa 3.11.b potential drop . . . . . . . . . . . . . . . . . . . . . . 14

Exa 3.11.c current . . . . . . . . . . . . . . . . . . . . . . . . . . 15Exa 3.11.d total resistance . . . . . . . . . . . . . . . . . . . . . . 16Exa 4.1.b power lost. . . . . . . . . . . . . . . . . . . . . . . . . 17Exa 4.1 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 17Exa 4.2 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 18Exa 4.3 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 18Exa 4.4.a power taken in parallel case . . . . . . . . . . . . . . . 19Exa 4.4.b power taken in series case . . . . . . . . . . . . . . . . 19Exa 4.5.a total load . . . . . . . . . . . . . . . . . . . . . . . . . 20Exa 4.5.b current taken . . . . . . . . . . . . . . . . . . . . . . . 20Exa 4.6 total cots of electric energy and total charges of bill. . 21

Exa 4.7 voltage current power and bill amount . . . . . . . . . 22Exa 4.8 current taken . . . . . . . . . . . . . . . . . . . . . . . 24Exa 4.9 amount of bills . . . . . . . . . . . . . . . . . . . . . . 24Exa 4.10.a total load of light and fans . . . . . . . . . . . . . . . 25

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Exa 4.10.b total load current . . . . . . . . . . . . . . . . . . . . 26

Exa 4.11 horsepower of the motor . . . . . . . . . . . . . . . . . 26Exa 4.12.a Bhp of the motor. . . . . . . . . . . . . . . . . . . . . 27Exa 4.12.b cost of the energy . . . . . . . . . . . . . . . . . . . . 28Exa 5.1 ECE of silver . . . . . . . . . . . . . . . . . . . . . . . 30Exa 5.2 thickness of coper . . . . . . . . . . . . . . . . . . . . 30Exa 5.3 resistance . . . . . . . . . . . . . . . . . . . . . . . . . 31Exa 5.4 potential difference. . . . . . . . . . . . . . . . . . . . 31Exa 6.1 field strength . . . . . . . . . . . . . . . . . . . . . . . 33Exa 6.2 force. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Exa 6.3 emf induced. . . . . . . . . . . . . . . . . . . . . . . . 34Exa 7.1.a emf induced. . . . . . . . . . . . . . . . . . . . . . . . 35

Exa 7.1.b emf generated . . . . . . . . . . . . . . . . . . . . . . 35Exa 7.2.a total armature current . . . . . . . . . . . . . . . . . . 36Exa 7.2.b current per armature path. . . . . . . . . . . . . . . . 36Exa 7.2.c emf generated . . . . . . . . . . . . . . . . . . . . . . 37Exa 7.3.a terminal voltage . . . . . . . . . . . . . . . . . . . . . 38Exa 7.3.b emf generated . . . . . . . . . . . . . . . . . . . . . . 38Exa 7.4.a terminal voltage . . . . . . . . . . . . . . . . . . . . . 39Exa 7.4.b emf generated . . . . . . . . . . . . . . . . . . . . . . 39Exa 7.4.c copper losses . . . . . . . . . . . . . . . . . . . . . . . 40Exa 7.4.d Bhp metric of the primemover . . . . . . . . . . . . . 41

Exa 7.4.e commercial efficiency. . . . . . . . . . . . . . . . . . . 42Exa 7.5.a total armature current . . . . . . . . . . . . . . . . . . 43Exa 7.5.b current . . . . . . . . . . . . . . . . . . . . . . . . . . 43Exa 7.5.c emf generated . . . . . . . . . . . . . . . . . . . . . . 44Exa 7.5.d power developed . . . . . . . . . . . . . . . . . . . . . 44Exa 7.5.e copper losses . . . . . . . . . . . . . . . . . . . . . . . 45Exa 7.5.f stray losses . . . . . . . . . . . . . . . . . . . . . . . . 46Exa 7.5.g.1 electrical efficiency . . . . . . . . . . . . . . . . . . . . 47Exa 7.5.g.2 commercial efficiency. . . . . . . . . . . . . . . . . . . 48Exa 7.5.g.3 mechanical efficiency . . . . . . . . . . . . . . . . . . . 48Exa 8.1 speed . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Exa 8.2.a Bhp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Exa 8.2.b copper losses . . . . . . . . . . . . . . . . . . . . . . . 51Exa 8.2.c armature torque . . . . . . . . . . . . . . . . . . . . . 52Exa 8.2.d shaft torque. . . . . . . . . . . . . . . . . . . . . . . . 52Exa 8.2.e lost torque . . . . . . . . . . . . . . . . . . . . . . . . 53

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Exa 8.2.f commercial efficiency. . . . . . . . . . . . . . . . . . . 54

Exa 8.3 speed . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Exa 8.4.a stray losses . . . . . . . . . . . . . . . . . . . . . . . . 55Exa 8.4.b horsepower of the motor . . . . . . . . . . . . . . . . . 56Exa 8.4.c efficiency . . . . . . . . . . . . . . . . . . . . . . . . . 57Exa 8.5.a back emf . . . . . . . . . . . . . . . . . . . . . . . . . 57Exa 8.5.b copper losses . . . . . . . . . . . . . . . . . . . . . . . 58Exa 8.5.c Bhp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Exa 8.5.d total torque . . . . . . . . . . . . . . . . . . . . . . . . 59Exa 8.5.e shaft torque. . . . . . . . . . . . . . . . . . . . . . . . 60Exa 8.5.f lost torque . . . . . . . . . . . . . . . . . . . . . . . . 60Exa 8.5.g commercial efficiency. . . . . . . . . . . . . . . . . . . 61

Exa 8.6 current taken . . . . . . . . . . . . . . . . . . . . . . . 62Exa 8.7 speed . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Exa 9.1 value of current flowing . . . . . . . . . . . . . . . . . 64Exa 9.2 value of current flowing . . . . . . . . . . . . . . . . . 64Exa 9.3 value of current flowing . . . . . . . . . . . . . . . . . 65Exa 9.4.a internal resistance . . . . . . . . . . . . . . . . . . . . 65Exa 9.4.b value of current flowing . . . . . . . . . . . . . . . . . 66Exa 9.5 emf of each cell and its internal resistance . . . . . . . 66Exa 9.6 ampere hour capacity . . . . . . . . . . . . . . . . . . 67Exa 9.7.a ampere hour efficiency . . . . . . . . . . . . . . . . . . 67

Exa 9.7.b watt hour efficiency . . . . . . . . . . . . . . . . . . . 68Exa 9.8.a initial charging current. . . . . . . . . . . . . . . . . . 68Exa 9.8.b final charging current . . . . . . . . . . . . . . . . . . 69Exa 9.9.a value and direction of current . . . . . . . . . . . . . . 69Exa 9.9.b total current . . . . . . . . . . . . . . . . . . . . . . . 70Exa 9.9.c power dissipated . . . . . . . . . . . . . . . . . . . . . 71Exa 9.10 direction of current and total resistance . . . . . . . . 72Exa 11.1 instantaneous emf . . . . . . . . . . . . . . . . . . . . 74Exa 11.2 rms value of alternating current. . . . . . . . . . . . . 74Exa 11.3 current drawn . . . . . . . . . . . . . . . . . . . . . . 75Exa 11.4 current . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Exa 11.5.a value of current flowing . . . . . . . . . . . . . . . . . 76Exa 11.5.b value of current flowing . . . . . . . . . . . . . . . . . 76Exa 11.6.a value of current flowing . . . . . . . . . . . . . . . . . 77Exa 11.6.b value of current flowing . . . . . . . . . . . . . . . . . 77Exa 11.7.a inductive reactance. . . . . . . . . . . . . . . . . . . . 78

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Exa 11.7.b impedance . . . . . . . . . . . . . . . . . . . . . . . . 78

Exa 11.7.c current . . . . . . . . . . . . . . . . . . . . . . . . . . 79Exa 11.7.d angle of phase difference . . . . . . . . . . . . . . . . . 79Exa 11.8 inductance and phase angle . . . . . . . . . . . . . . . 80Exa 11.9 capacitance . . . . . . . . . . . . . . . . . . . . . . . . 81Exa 11.10.aimpedance . . . . . . . . . . . . . . . . . . . . . . . . 81Exa 11.10.bcurrent . . . . . . . . . . . . . . . . . . . . . . . . . . 82Exa 11.10.cphase angles . . . . . . . . . . . . . . . . . . . . . . . 82Exa 11.10.dvoltage . . . . . . . . . . . . . . . . . . . . . . . . . . 83Exa 11.10.evoltage across the coil . . . . . . . . . . . . . . . . . . 83Exa 11.10.ftotal power taken . . . . . . . . . . . . . . . . . . . . 84Exa 11.11.atotal impedance . . . . . . . . . . . . . . . . . . . . . 85

Exa 11.11.bcurrent taken . . . . . . . . . . . . . . . . . . . . . . . 85Exa 11.11.cpower factor . . . . . . . . . . . . . . . . . . . . . . . 86Exa 11.12.acurrent taken . . . . . . . . . . . . . . . . . . . . . . . 87Exa 11.12.bphase angle . . . . . . . . . . . . . . . . . . . . . . . . 88Exa 11.12.cseries equivalent arrangement of resistance and reactance 89Exa 12.1.a line current and phase current . . . . . . . . . . . . . 92Exa 12.1.b line current and phase current . . . . . . . . . . . . . 92Exa 12.2.a line current and total power . . . . . . . . . . . . . . . 93Exa 12.2.b line current and total power . . . . . . . . . . . . . . . 94Exa 12.3.a current in each phase of the motor . . . . . . . . . . . 94

Exa 12.3.b current in each phase of the generator . . . . . . . . . 95Exa 12.4 reading . . . . . . . . . . . . . . . . . . . . . . . . . . 96Exa 12.5.a power factor when both readings are positive . . . . . 96Exa 12.5.b power factor . . . . . . . . . . . . . . . . . . . . . . . 97

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Chapter 3

electricity and its fundamental

law

Scilab code Exa 3.1 resistance

1 / / Example 3 . 1 // r e s i s t a n c e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 V = 2 3 0 ; // i n v o l t s7 I = 1 0 ; // i n A8 R = V / I ;

9 disp (R , r e s i s t a n c e o f e l em e nt , R( ohm )= )

Scilab code Exa 3.2 voltage

1 / / Example 3 . 2 // v o l t a g e2 clc ;

3 clear ;

4 close ;

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5 / / g i v e n d at a :

6 R 1 = 0 . 5 ; // minimum v a lu e o f r e s i s t a n c e i n ohm7 R 2 = 2 0 ; // maximum v a l u e o f r e s i s t a n c e i n ohm8 I = 1 . 2 ; // c u r r e n t i n A9 V 1 = I * R 1 ;

10 V 2 = I * R 2 ;

11 disp ( V 1 , v o l t a g e d ro p i n I s t c as e , V1 (V) = )12 disp ( V 2 , v o l t a g e d ro p i n I I n d c a se , V2 (V) = )

Scilab code Exa 3.3 specific resistance


3 clear ;

4 close ;

5 / / g i v e n d at a :6 L = 1 0 0 0 ; // l e n g th o f w ir e i n cm7 d = 0 . 1 4 ; // d i a me te r o f w ir e i n cm8 R 1 = 2 . 5 * 1 0 ^ 6 ; // r e s i s t a n c e i n mi croohm9 a = ( % p i * d ^ 2 ) / 4 ; // c r o s s s e c t i o n a re a

10 p = ( R 1 * a ) / L ;11 disp (p , t h e s p e c i f i c r e s i s t a n c e , p ( m i cr oohmc m ) = )



3 clear ;

4 close ;5 / / g i v e n d at a :6 R t 1 = 5 4 . 3 ; // r e s i s t a n c e i n ohm7 a l f a = 0 . 0 0 4 3 ; // t he r e s i s t a n c e t em pe ra tu re o f

c o e f i c i e n t i n p er d eg re e c e l c i u s

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8 t 1 = 2 0 ; // t em pe ra tu re i n d e g r e e c e l c i u s

9 t 2 = 4 0 ; // t em pe ra tu re i n d e g r e e c e l c i u s10 R t 2 = ( R t 1 * ( 1 + ( a l f a * t 2 ) ) ) / ( 1 + ( a l f a * t 1 ) ) ;11 disp ( R t 2 , r e s i s t a n c e a t 40 d e gr e e c e l s i u s , Rt2 ( ohm ) =

)

Scilab code Exa 3.5.a total resistance

1 // Example 3 . 5 . a // r e s i s t a n c e

2 clc ;3 clear ;

4 close ;

5 / / g i v e n d at a :6 r 1 = 3 0 ; // r e s i s t a n c e i n ohm7 r 2 = 3 5 ; // r e s i s t a n c e i n ohm8 r 3 = 4 5 ; // r e s i s t a n c e i n ohm9 R = r 1 + r 2 + r 3 ;

10 disp (R , t o t a l r e s i s t a n c e , R( ohm ) = )

Scilab code Exa 3.5.b current flowing

1 / / Example 3 . 5 . b / / c u r r e n t2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 r 1 = 3 0 ; // r e s i s t a n c e i n ohm7 r 2 = 3 5 ; // r e s i s t a n c e i n ohm

8 r 3 = 4 5 ; // r e s i s t a n c e i n ohm9 R = r 1 + r 2 + r 3 ;

10 V = 2 2 0 ;

11 I = V / R ;

12 disp (I , c u r r e n t , I (A) = )

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1 / /Example 3 . 6 // v o l t a g e a t t he g e n e r a t i n g s t a t i o n2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 I = 7 5 ; // c u r r e n t i n A

7 R = 0 . 1 5 ; // r e s i s t a n c e i n ohm8 v = 2 2 0 ; // v o l t a g e i n v o l t s9 V 1 = I * R ; // v o lt a g e dr op o f t he f e e d e r i n s e c t i o n AB

10 V 2 = I * R ; // v o lt a g e dr op o f t he f e e d e r i n s e c t i o n CD11 V _ t o t a l = V 1 + V 2 ; // t o t a l v o l t a ge dr op i n t he l e a d and

r e tu r n f e e d e r12 V = v + V _ t o t a l ;

13 disp (V , v o l t ag e a t t he g e n e r a t i n g s t a ti o n , V( v ) = )

Scilab code Exa 3.7 total resistance

1 // Example 3 . 7 // t o t a l r e s i s t a n c e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 r 1 = 6 ; // r e s i s t a n c e i n ohm7 r 2 = 1 0 ; // r e s i s t a n c e i n ohm8 r 3 = 1 5 ;

// r e s i s t a n c e i n ohm9 r = ( 1 / r 1 ) + ( 1 / r 2 ) + ( 1 / r 3 ) ;10 R = 1 / r ;

11 disp (R , e q u i v a l e n t r e s i s t a n c e , R( ohm ) = )

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1 / / Example 3 . 8 // v o l t a g e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 I = 5 ; // c u r r e n t i n A7 n = 2 ; // number o f r e s i s t a n c e i n p a r a l l e l o f s e c t i o n

BC8 r 1 = 1 5 ; // r e s i s t a n c e i n ohm9 r 2 = 2 0 ; // r e s i s t a n c e i n ohm

10 r 3 = 6 0 ; // r e s i s t a n c e i n ohm11 r 4 = 6 4 ; // r e s i s t a n c e i n ohm12 r 5 = 6 4 ; // r e s i s t a n c e i n ohm13 r 6 = 2 . 5 ; // r e s i s t a n c e i n ohm14 R 1 = r 4 / n ; // e q u i v a l e n t r e s i s t a n c e o f s e c t i o n BC15 R 2 = ( r 1 * r 2 * r 3 ) / ( ( r 1 * r 2 ) + ( r 2 * r 3 ) + ( r 3 * r 1 ) ) ; //

e q u i v a l e n t r e s i s t a n c e o f s e c t i o n CD

16 R = R 1 + R 2 + r 6 ; // e q ui v a l e n t r e s i s t a n c e o f s e c t i o n AD17 V = I * R ;

18 disp (V , v o l t a g e , V( v ) = )

Scilab code Exa 3.9 effective resistance and current

1 / / Example 3 . 9 // r e s i s t a n c e and c u r r e nt2 clc ;

3 clear ;4 close ;

5 / / g i v e n d at a :6 V = 2 4 0 ; // v o l t a g e i n v o l t s7 r 1 = 2 ; // r e s i s t a n c e i n ohm

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8 r 2 = 3 ; // r e s i s t a n c e i n ohm

9 r 3 = 8 . 8 ; // r e s i s t a n c e i n ohm10 r 4 = 1 0 ; // r e s i s t a n c e i n ohm11 r 5 = 3 ; // r e s i s t a n c e i n ohm12 R 1 = ( r 1 * r 2 ) / ( r 1 + r 2 ) ; // e q u i v a l e n t r e s i s t a n c e o f

p a r a l l e l br a nc h13 R 2 = R 1 + r 3 ; // e q ui v a l e n t r e s i s t a n c e o f s e c t i o n ABC14 R 3 = ( R 2 * r 4 ) / ( R 2 + r 4 ) ;

15 R = R 3 + r 5 ; // t o t a l r e s i s t a n c e o f s e c t i o n AD16 I = V / R ;

17 V 1 = I * r 5 ; // v o l t a ge dr op a c r o s s r 518 V 2 = V - V 1 ; // v o l t a g e dr op a c r o s s s e c t i o n ABC

19 I 1 = V 2 / r 4 ; // c u r r e n t f l o w i n g t h r o ug h r 4 r e s i s t a n c e20 I 2 = I - I 1 ; // c ur r e nt i n r 3 r e s i s t a n c e21 V 3 = I 2 * r 3 ; // v o l t a ge dro p a c r o s s r 3 r e s i s t a n c e ,

s e c t i o n ABC22 V 4 = V 2 - V 3 ; // v o l t a g e d ro p b et we en s e c t i o n AB23 I 3 = V 4 / r 1 ; // c u r r e n t f l o w i n g t h r o ug h r 1 r e s i s t a n c e24 I 4 = V 4 / r 2 ; // c u r r e nt f l o w i n g t h r o u g h r 2 r e s i s t a n c e25 disp ( I 3 , c u r r en t f l o w i n g t hr ou gh r 1 ( 2 ohms )

r e s i s t a n c e , I 3 (A) = )26 disp ( I 4 , c u r r en t f l o w i n g t hr ou gh r 2 ( 3 ohms )

r e s i s t a n c e , I 4 (A) = )

27 disp (R , t o t a l r e s i s t a n c e , R( ohm ) = )28 disp ( V 1 , v o l t a g e d ro p a c r o s s r 5 ( 3 ohms ) r e s i s t a n c e ,

V 1 ( V ) = )29 disp ( V 2 , v o l t a g e d ro p a c r o s s s e c t i o n ABC, V2 (V) = )30 disp ( V 3 , v o l t a g e dr op a c r o s s r 3 r e s i s t a n c e ( 8 . 8 ohms )

, V 3 ( V ) = )31 disp ( V 4 , v o l t a g e d ro p b et we en s e c t i o n AB, V4 (V) = )

Scilab code Exa 3.10 current

1 / / Example 3 . 1 0 / / c u r r e n t2 clc ;

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3 clear ;

4 close ;5 / / g i v e n d at a :6 I = 4 4 ; // c u r r e n t i n A7 r 1 = 6 ; // r e s i s t a n c e i n ohm8 r 2 = 1 2 ; // r e s i s t a n c e i n ohm9 r 3 = 1 8 ; // r e s i s t a n c e i n ohmr1

10 a = ( 1 / r 1 ) + ( 1 / r 2 ) + ( 1 / r 3 ) ;

11 R = 1 / a ;

12 V = I * R ;

13 i 1 = V / r 1 ;

14 i 2 = V / r 2 ;

15 i 3 = V / r 3 ;16 disp ( i 1 , c u r r e n t i n 6 ohm r e s i s t a n c e , i 1 (A) = )17 disp ( i 2 , c u r r e n t i n 1 2 ohm r e s i s t a n c e , i 2 (A) = )18 disp ( i 3 , c u r r e n t i n 1 8 ohm r e s i s t a n c e , i 3 (A) = )

Scilab code Exa 3.11.a unknow resistance

1 // Example 3 . 1 1 .A // RESISTANCE

2 clc ;3 clear ;

4 close ;

5 t = 1 5 ; //TOTAL CURRENT IN AMPERES6 i 1 = 2 ; //CURRENT THROUGH UNKNOWN RESISTANCE7 R 1 = 1 5 ; // i n ohms8 R 2 = 5 0 / 2 ; // i n ohms9 x = ( t - i 1 ) * ( ( R 1 * R 2 ) / ( R 1 + 2 * R 2 ) ) ; // unknown r e s i s t a n c e i n

ohms)10 disp (x , unknown r e s i s t a n c e i n ohms )

Scilab code Exa 3.11.b potential drop

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1 / / Example 3 . 1 1 . B // p o t e n t i a l dr op a c r o s s t he

c i r c u i t2 clc ;3 clear ;

4 close ;


ohms10 P D = i 1 * x ; // i n v o l t s

11 disp ( P D , p o t e n t i a l dr op a c ro s s t h e c i r c u i t i n v o l t si s )

Scilab code Exa 3.11.c current

1 // Examp le 3 . 1 1 . C // CURRENT IN EACH RESISTANCE2 clc ;

3 clear ;

4 close ;5 t = 1 5 ; //TOTAL CURRENT IN AMPERES6 i 1 = 2 ; //CURRENT THROUGH UNKNOWN RESISTANCE7 R 1 = 1 5 ; // i n ohms8 R 2 = 5 0 / 2 ; // i n ohms9 x = ( t - i 1 ) * ( ( R 1 * R 2 ) / ( R 1 + 2 * R 2 ) ) ; // unknown r e s i s t a n c e i n

ohms10 P D = i 1 * x ; // i n v o l t s11 i 5 = P D / ( 2* R 2 ) ; // c u r r e n t i n 5 ohms r e s i s t a n c e12 i 1 5 = P D / R 1 ; // c u r r e nt i n 15 ohms r e s i s t a n c e

13 disp ( i 5 , c u r r e nt i n 5 ohms r e s i s t a n c e i n ampere )14 disp ( i 1 5 , c u r r e nt i n 15 ohms r e s i s t a n c e i n ampere )

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Scilab code Exa 3.11.d total resistance

1 // Example 3 . 1 1 . d // t o t a l r e s i s t a n c e2 clc ;

3 clear ;

4 close ;


ohms

10 P D = i 1 * x ; // i n v o l t s11 R X = ( ( 1 / R 1 ) + ( 1 / ( 2 * R 2 ) ) + ( 1 / x ) ) ; //12 R = 1 / R X ; //13 disp (R , t o t a l r e s i s t a n c e o f t h e c i r c u i t i n ohms )

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Chapter 4

Work power and energy

Scilab code Exa 4.1.b power lost

1 / / Example 4 . 1 . b / / p ow er l o s t2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 I = 1 1 ; // c u r r e n t i n A

7 V 1 = 5 5 ; // v o l t a g e i n V8 V 2 = 2 2 0 ; // v o l t a g e i n V9 V = V 2 - V 1 ;

10 R = V / I ;

11 P = I ^ 2 * R ;

12 disp (P , p o we r l o s t , P (W) = )


1 // Example 4 . 1 . a // r e s i s t a n c e2 clc ;

3 clear ;

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4 close ;

5 / / g i v e n d at a :6 I = 1 1 ; // c u r r e n t i n A7 V 1 = 5 5 ; // v o l t a g e i n V8 V 2 = 2 2 0 ; // v o l t a g e i n V9 V = V 2 - V 1 ;

10 R = V / I ;

11 disp (R , r e s i s t a n c e , R( ohm ) = )


1 // Example 4 . 2 : r e s i s t a n c e o f e a c h c o i l2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 V = 3 0 0 ; // v o l t a g e i n v o l t s7 W = 3 6 0 ; // power l o s t i n one c o i l i n wat t8 I = 6 ; // c u r r e n t i n A9 R 1 = V / I ;

10 R = V ^ 2 / W ;11 a = ( 1 / R 1 ) - ( 1 / R ) ;

12 r 2 = 1 / a ;

13 disp (R , r e s i s t a n c e o f 3 60W c o i l 1 ,R( ohm ) = )14 disp ( r 2 , r e s i s t a n c e o f s ec on d c o i l 2 , r 2 ( ohm ) = )


1 / /Example 4 . 3 : r e s i s t a n c e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :

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6 W 1 = 1 0 0 ; // i n wat t

7 E = 1 1 0 ; // i n v o l t s8 W 2 = 6 0 ; // i n w att9 I 1 = W 1 / E ; // c u r r e n t t ak en by 1 00 w l amp

10 I 2 = W 2 / E ; / / c u r r e n t t a k en by 6 0W l amp11 I = I 1 - I 2 ;

12 R = E / I ;

13 disp (R , r e s i s t a n c e , R( ohm ) = )

Scilab code Exa 4.4.a power taken in parallel case

1 // Example 4 . 4 . a : power i n c a se o f p a r a l l e l2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 w = 1 0 0 ; // i n wat t7 V = 2 2 0 ; // v o l t a g e i n v o l t s8 R 1 = V ^ 2 / w ;

9 R = R 1 / 2 ; // t o t a l r e s i s t a n c e o f t h e c i r c u i t

10 I = V / R ;11 W = I ^ 2 * R ;

12 disp (W , p ower i n c a s e o f p a r a l l e l ,W( w at t ) = )

Scilab code Exa 4.4.b power taken in series case

1 // Example 4 . 4 . b : power i n c a s e o f s e r i e s2 clc ;

3 clear ;4 close ;

5 / / g i v e n d at a :6 w = 1 0 0 ; // i n wat t7 V = 2 2 0 ; // v o l t a g e i n v o l t s

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8 R 1 = V ^ 2 / w ;

9 R 2 = V ^ 2 / w ;10 R = R 1 + R 2 ; // t o t a l r e s i s t a n c e o f t h e c i r c u i t11 I = V / R ;

12 W = I ^ 2 * R ;

13 disp (W , p ower i n c a s e o f s e r i e s ,W( w at t ) = )

Scilab code Exa 4.5.a total load

1 / / Example 4 . 5 . a : t o t a l l o a d2 clc ;3 clear ;

4 close ;

5 / / g i v e n d at a :6 l = 3 0 0 ; / / number o f l am ps7 w 1 = 6 0 ; // i n wat t8 W 1 = w 1 * l ; // w at ta ge r e q u i r e d f o r 3 00 lamps , 60 w att

e a c h9 w 2 = 4 0 ; // i n wat t

10 f = 1 0 0 ; // number o f f a n

11 W 2 = w 2 * f ; // w at ta ge r e q ui r e d f o r 100 f an s , 40 wat te a c h

12 W = ( W 1 + W 2 ) * 1 0 ^ - 3 ;

13 disp (W , t o t a l l o a d ,W( k i l o w a tt ) = )

Scilab code Exa 4.5.b current taken

1 / / Example 4 . 5 . b : c u r r e n t t a ke n by l o a d

2 clc ;3 clear ;

4 close ;

5 / / g i v e n d at a :6 V = 2 2 0 ; // v o l t a g e i n v o l t s

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7 l = 3 0 0 ; / / number o f l am ps

8 w 1 = 6 0 ; // i n wat t9 W 1 = w 1 * l ;10 w 2 = 4 0 ; // i n wat t11 f = 1 0 0 ; // number o f f a n12 W 2 = w 2 * f ;

13 W = ( W 1 + W 2 ) * 1 0 ^ - 3 ;

14 I = ( W * 1 0 0 0 ) / V ;

15 disp (I , c u r r e n t , I (A) = )

Scilab code Exa 4.6 total cots of electric energy and total charges of bill

1 / / Example 4 . 6 // t o t a l c o s t o f e l e c r i c c h a rg e2 clc ;

3 clear ;

4 close ;

5 n l = 1 2 ; / / no . o f l am ps6 w l = 1 0 0 ; // w a t ta g e o f l am ps7 h l = 6 ; / / e ac h l am ps work 6 h o ur s a d ay s8 w 1 2 = w l * n l * h l ; / / w at ta g e o f 1 2 l am ps i n Wh

9 n f = 6 ; // no . o f f a ns10 w f = 6 0 ; // w a tt ag e o f f a n s11 h f = 5 ; // e a ch f a n s work 5 h ou rs a d ay s12 w 6 = w f * n f * h f ; // w a tt ag e o f 12 f a n s i n Wh13 n c = 2 ; / / n o . o f e l e c t r i c c o o k e r s14 w c = 1 5 0 0 ; / / w a t t a g e o f e l e c t r i c c o o k e r s15 h c = 4 ; / / e a ch e l e c t r i c c o o k e r s wor k 4 h o u r s a d ay s16 w 2 = w c * n c * h c ; / / w a t ta g e o f 2 e l e c t r i c c o o k e r s i n Wh17 n g = 2 ; // no . o f g y s e rs18 w g = 1 0 0 0 ; // w a tt ag e o f e ac h g y s er

19 h g = 3 ; // e a ch g y s e r wo rk s 3 h ou rs a day20 w 2 1 = w g * h g * n g ; // t o t a l w at ta ge o f g y s e r s i n Wh21 t c g = ( w 1 2 + w 6 ) * 1 0 ^ - 3 ; //TOTAL WATTAGE OF LAMPS AND FANS22 C c g = 4 0 ; // IN PAISA23 E cg = ( t c g * C cg * 3 0 ) / 1 0 0; //TOTAL ENERGY CHARGES @40

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PAISA PER UNIT

24 t c g 1 = ( w 2 + w 2 1 ) * 1 0 ^ - 3 ; //TOTAL WATTAGE OF COOKERS ANDGYSERS25 C c g 1 = 3 5 ; // IN PAISA26 E c g1 = ( t c g 1 * C c g1 * 3 0 ) / 1 0 0 ; //TOTAL ENERGY CHARGES @35

PAISA PER UNIT27 t c = E c g + E c g 1 ; // IN RUPPES28 disp ( E c g , t o t a l c o s t o f e l e c t r i c c h a rg e @40 p a i s a

p er u ni t i n r up ee s )29 disp ( E c g 1 , t o t a l c o s t o f e l e c t r i c c h a rg e @35 p a i s a

p er u ni t i n r up ee s )30 disp ( t c , t o t a l c ha rg e f o r l i g h and power i n r u pe es )

Scilab code Exa 4.7 voltage current power and bill amount

1 // Example 4 . 7 // t o t a l c on su mp ti on o f f a c t o r y i nk i l l o wat ts

2 clc ;

3 clear ;

4 close ;

5 n l = 4 0 0 ; / / no . o f l am ps6 w l = 1 0 0 ; // w a t ta g e o f l am ps7 w 4 0 0 = w l * n l ; // w a tt ag e o f 40 0 l am ps i n W8 n f = 1 0 0 ; // no . o f f a ns9 w f = 4 0 ; // w a tt ag e o f f a n s

10 w 6 = w f * n f ; // w at ta ge o f 100 f a ns i n W11 n c = 2 0 0 ; // no . o f w a ll s c o k e ts12 w c = 6 0 ; // w at ta ge o f w a ll s c c k e t s13 w 2 = w c * n c ; // w at ta ge o f 200 w a ll s o c k e ts i n Wh14 t c = w 4 00 + w 6 + w 2 ; / / t o t a l c o ns u mp t io n i n kW

15 t c = w 4 00 + w 6 + w 2 ; / / t o t a l c o ns u mp t io n i n kW16 h = 5 ; // h o ur s17 l l = t c * 1 0 ^ - 3 * h ; // l i g h t n i n g l o a d i n kWh18 V = 2 5 0 ; // i n v o l t s19 I = 2 0 ; / / i n a m p e r es

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20 M l = V * I * 1 0 ^ - 3 ; // m i s c e l l a n e o u s l o a d s i n kW

21 M l = V * I * 1 0 ^ - 3 ; // m i s c e l l a n e o u s l o a d s i n kW22 h m = 2 ; // hou r s23 h l = 5 0 ; / / h e a t i n g l o a d i n kW24 M h p = 4 0 ; //BNHP25 M o = ( ( 5 0 *8 0 * 7 46 ) / ( 1 0 0* 1 0 0 0) ) ; //MOTOR AT 80% LOAD IN

Kw26 t l = t c * 1 0 ^ - 3 + M l + h l + M o ; // t o t a l l o ad i n kW27 disp ( t l , t o t a l l o a d i s , ( kW)= )28 I t = ( t l * 1 0 ^3 ) / V ; // t o t a l c u r r e n t t ak en buy t he

f a c t o r y i n a mp er es29 disp ( I t , t o t a l c u r r e nt t ak en by t he f a c t o r y i s , ( A)=

)30 r = 0 . 0 3 ; // IN OHMS31 V c = I t * r ; // v o l t a g e drop i n t he c a bl e32 V s = V c + V ; // v o l t a g e a t t he s en d in g end o f t he f e e d e r

i n v o l t s33 disp ( V s , v o l t a ge a t t he s en di ng end o f t h e f e e d e r i s

, ( V ) )34 r = 0 . 0 3 ; // IN OHMS35 V c = I t * r ; // v o l t a g e drop i n t he c a bl e36 P w = I t ^ 2 * r ; / / p o we r w a s te d i n kW37 disp ( P w * 1 0 ^ - 3 ,

p ow er w a st ed i s , (kW) )

38 M l h = M l * h m ; / / m i s c e l l a n e o u s l o a d i n kWh39 t e = M l h + l l ; //TOTAL ENERGY COSNUMED PER DAY40 N u = t e * 6 ; //NO. OF UNITS41 E c = ( N u * 3 0 ) / 1 0 0 ; // ENERGY CHARGE @30 PAISA PER UNIT42 e C M = E c + 2 + 3 4 . 8 0 ; //TOTAL CHARGE AFTER TAX AND RENT IN

RUPEES43 h l = 5 0 ; / / h e a t i n g l o a d i n kW44 h l h = 5 0 * 4 ; / / h e a t i n g l o a d i n kWh45 M o h = M o * 8 ; //MOTOR LOAD IN kWh46 T E P = h l h + M o h ; // t o t a l e ne rg y p er day

47 t e p l = T E P * 6 ; // t o t a l e ne rg y i n 6 d ay s48 t e p c = ( t e p l * 3 5 ) / 1 0 0 ; // e ne rg y c h a rg e s @35 p a i s a p er

u n i t i n r up ee s49 t e p c l = t e p c + 5 0 + 7 8 . 9 6 ; // t o t a l c h ar g es i n r u pe s s50 disp ( e C M , t o t a l l i g h t n i n g c ha r g e s i n c l u d i n g m e te r

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r e n t and e l e c t r i c y t ax i s , ( Rs )= )

51 disp ( t e p c l , t o t a l power c h ar g es i n c l u d i ng me t er r e n tand e l e c t r i c y t ax i s , ( Rs )= )52 g t = t e p c l + e C M ; //53 disp ( g t , g r an d t o t a l o f b i l l s i s , ( Rs )= )

Scilab code Exa 4.8 current taken

1 / / Example 4 . 8 : c u r r e nt t ak en by l o ad

2 clc ;3 clear ;

4 close ;

5 / / g i v e n d at a :6 V = 2 5 0 ; // v o l t a g e i n v o l t s7 L = 5 * 7 4 6 ; / / 1 hp =746 w a tt8 e t a = 8 0 ; // e f i c i e n c y o f motor i n %9 I n p u t = ( L * 1 0 0 ) / 8 0 ;

10 I = I n p u t / V ;

11 disp (I , c u r e e n t , I (A ) = )

Scilab code Exa 4.9 amount of bills

1 / / Exam ple 4 . 9 / / t o t a l o f b i l l s2 clc ;

3 clear ;

4 close ;

5 p = 3 0 ; / / h o r s e p ow er o f m ot or6 r = 2 4 ; / / r u p e e s p e r kWh

7 e c = 3 5 ; // p a i s a p er u n i t8 n = 8 0 ; // p e r ce n t ag e o f l o ad9 t = 8 ; // i n h ou rs

10 d = 2 5 ; // t o t a l d ay s11 n e = 9 6 ; // e f f i c i e n c y o f motor i n p e rc e nt a ge

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12 m o = ( n * p ) / 1 0 0 ; // o u tp ut o f motor a t 80% o f l o ad

13 m i = ( m o * 1 0 0 * 7 4 6 ) / ( n e ) ; // i n pu t o f motor i n w at ts14 e c m = m i * 1 0 ^ - 3 * t * d ; / / e n e r g y c on su me d i n a month15 e c u = ( e c m * 3 5 ) / 1 0 0 ; / / e n e r g y c h a r g e s16 m i d = ( 3 0 * 1 0 0 * 7 4 6 ) / ( n e * 1 0 0 0 ) ; // i n p u t o f mo to r i n kW a t

demanded17 e c u d = ( m i d * 2 4 ) ; // demanded c o n n e c t i o n i n r u p e e s18 t a = e c u + e c u d ; // t o t a l b i l l i n r u pe e s19 disp ( t a , t o t a l b i l l i n r up e e s i s )

Scilab code Exa 4.10.a total load of light and fans

1

2 // Example 4 . 1 0 . a // t o t a l l oa d o f l i g h t s and f a ns3 clc ;

4 clear ;

5 close ;

6 l p = 5 0 ; // no . o f l i g h t p o i n t s7 l w = 6 0 ; // w at t a ge o f l i g h t p o i n t s8 f p = 2 0 ; // no . o f f an p o i nt s

9 f w = 1 0 0 ; // w at ta ge o f f an p o i n ts10 w p p = 1 0 ; // no . o f w a ll p lu g p o i nt s11 w p p w = 6 0 ; // w at ta ge o f w a ll p lu g p o i nt s12 b p = 5 ; // no . o f b e l l p o i n t s13 b p w = 4 0 ; // w at t a g e o f b e l l p o i n t s14 p p p = 8 ; / / po wer p l ug p o i n t s15 p p p w = 5 0 0 0 ; // w a tt ag e o f power p lu g p o i n t s16 l p w = l p * l w ; / / w at ta g e o f 5 0 l a mp s17 f p w = f p * f w ; // w at ta ge o f 20 f a ns18 w p p p w = w p p * w p p w ; // w at ta ge o f w a ll p lu g p o i n ts

19 b p w w = b p * b p w ; // w at t a ge o f b e l l p o i n t s20 t l = l p w + f p w + w p p p w + b p w w ; // t o t a l w at ta g e21 disp ( t l , t o t a l w a t t a ge o f l i g h t n i n g l oa d i s i n w a tt s

)

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Scilab code Exa 4.10.b total load current

1 / / Example 4 . 1 0 . b // t o t a l l o a d o f p ower c o n n e c t i o n2 clc ;

3 clear ;

4 close ;

5 V = 4 0 0 ; // t h r e e p ha se v o l t a g e6 l p = 5 0 ; // no . o f l i g h t p o i n t s7 l w = 6 0 ; // w at t a ge o f l i g h t p o i n t s8 f p = 2 0 ; // no . o f f an p o i nt s9 f w = 1 0 0 ; // w at ta ge o f f an p o i n ts

10 w p p = 1 0 ; // no . o f w a ll p lu g p o i nt s11 w p p w = 6 0 ; // w at ta ge o f w a ll p lu g p o i nt s12 b p = 5 ; // no . o f b e l l p o i n t s13 b p w = 4 0 ; // w at t a g e o f b e l l p o i n t s14 p p p = 8 ; / / po wer p l ug p o i n t s15 p p p w = 5 0 0 ; // w a tt ag e o f power p lu g p o i n t s16 l p w = l p * l w ; / / w at ta g e o f 5 0 l a mp s17 f p w = f p * f w ; // w at ta ge o f 20 f a ns

18 w p p p w = w p p * w p p w ; // w at ta ge o f w a ll p lu g p o i n ts19 b p w w = b p * b p w ; // w at t a ge o f b e l l p o i n t s20 t l = l p w + f p w + w p p p w + b p w w ; // t o t a l w at ta g e21 p p p p w = p p p * p p p w ; // w a tt ag e o f power p lu g p o i n t s22 t w = t l + p p p p w ; // t o t a l w at ta g e23 I l = ( t l / V ) ; // CURRENT THROUGH LIGHTNING LOAD24 I p = p p p p w / V ; // c u r r en t t hr ou gh power l o ad25 t t l = I l + I p ; // t o t a l l oa d c ur e n t26 disp ( t t l , t o t a l l oa d c u r r e n t i n ampe re s )

Scilab code Exa 4.11 horsepower of the motor

1 / / Example 4 . 1 1 : h o r s e p ower

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2 clc ;

3 clear ;4 close ;

5 / / g i v e n d at a :6 h = 3 0 ; // i n m7 F l = 1 0 ; / / f r i c t i o n l o s s i n %8 H l = ( F l / 1 0 0 ) * h ;

9 t o t a l _ H = h + H l ;

10 e t a = 9 0 ; // e f i c i e n c y o f pump11 w = 1 0 0 0 ; // w at er w ei gh t i n kg12 f l o w _ r a t e = 2 4 3 ; // i n p er ho ur13 W _ d o n e = ( f l o w _ r a t e * w * t o t a l _ H ) / 6 0 ; // i n kgm/min

14 o u t p u t = W _ d o n e / 4 5 0 0 ; // o u tp u t o f pump i n hp15 i n = ( o u t p u t * 1 0 0 ) / e t a ;

16 O = i n ;

17 disp (O , o u t pu t o f t h e motor , O( hp ) = )

Scilab code Exa 4.12.a Bhp of the motor

1

2 / / E xa mp le 4 . 1 2 . a : BHP o f t h e m ot or3 clc ;

4 clear ;

5 close ; n = 8 0 ; // e f f i c i e n c y6 l = 7 . 5 ; / / l o a d i n t o n ne s7 h = 1 3 5 ; / / h e i g h t i n m e te r s8 c = 0 . 5 ; / / c g e w e ig h t i n t o n ne s9 b = 3 ; // b a l a n c e w e ig h t i n t o n ne s

10 t d = 9 0 ; // t i me i n s e co n d s11 o n e t = 1 0 0 0 ; // i n kg

12 o n e h p = 7 4 6 ; / / w a t t13 w l = l + c - b ; / / w e i g h t l i f t e d d u r i n g u pwa rd j o u r n e y i nt o n n e s

14 w l d = b - c ; / / w e i g h t l i f t e d d u r i n g do wnward j o u r n e y i nt o n n e s

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15 w d u = ( w l * 1 0 ^ 3 * h * 6 0 ) / t d ; / / wor k d on e by t h e l i f t p e r

m in ut e d u r i n g upward j o u r n e y16 w d d = ( w l d * 1 0 ^ 3 * h * 6 0 ) / t d ; / / wo rk d on e by t h e l i f t p e rm i nu t e d u r i n g do wnward j o u r n e y

17 m o u = w d u / 4 5 0 0 ; // i n hp18 m i u = ( m o u * 1 0 0 * 7 4 6 ) / ( n * 1 0 0 0 ) ; // i n pu t o f motor i n kW19 m o d = w d d / 4 5 0 0 ; // i n hp20 m i d = ( m o d * 1 0 0 * 7 4 6 ) / ( n * 1 0 0 0 ) ; // i n pu t o f motor i n kW21 disp ( m o u , BHP o f t h e m ot or i n upward j o u r n e y i n hp )22 disp ( m o d , BHP o f t h e m ot or i n downward j o u r n e y i n hp

)

Scilab code Exa 4.12.b cost of the energy

1 // Example 4 . 1 2 . b : c o s t o f t he e ne rg y2 clc ;

3 clear ;

4 close ; n = 8 0 ; // e f f i c i e n c y5 l = 7 . 5 ; / / l o a d i n t o n ne s6 h = 1 3 5 ; / / h e i g h t i n m e te r s

7 c = 0 . 5 ; / / c g e w e ig h t i n t o n ne s8 b = 3 ; // b a l a n c e w e ig h t i n t o n ne s9 t d = 9 0 ; // t i me i n s e co n d s

10 o n e t = 1 0 0 0 ; // i n kg11 o n e h p = 7 4 6 ; / / w a t t12 w l = l + c - b ; / / w e i g h t l i f t e d d u r i n g u pwa rd j o u r n e y i n

t o n n e s13 w l d = b - c ; / / w e i g h t l i f t e d d u r i n g do wnward j o u r n e y i n

t o n n e s14 w d u = ( w l * 1 0 ^ 3 * h * 6 0 ) / t d ; / / wor k d on e by t h e l i f t p e r

m in ut e d u r i n g upward j o u r n e y15 w d d = ( w l d * 1 0 ^ 3 * h * 6 0 ) / t d ; / / wo rk d on e by t h e l i f t p e rm i nu t e d u r i n g do wnward j o u r n e y

16 m o u = w d u / 4 5 0 0 ; // i n hp17 m i u = ( m o u * 1 0 0 * 7 4 6 ) / ( n * 1 0 0 0 ) ; // i n pu t o f motor i n kW

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18 m o d = w d d / 4 5 0 0 ; // i n hp

19 m i d = ( m o d * 1 0 0 * 7 4 6 ) / ( n * 1 0 0 0 ) ; // i n pu t o f motor i n kW20 t c = m i u + m i d ; / / t o t a l e n er g y c on su mp ti on i n kW21 E h = t c * 1 0 ; // t o t a l e ne rg y c o n su p t io n p er h ou r22 r a t e = 4 0 ; // r a t e i n p a i sa23 c e = E h * ( r a t e / 1 0 0 ) ; // c o s t o f e ne rg y i n r up e e s24 disp ( c e , c o s t o f e ne rg y i n r up e e s i s )

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Chapter 5

effects of electric current

Scilab code Exa 5.1 ECE of silver

1 / / Example 5 . 1 : E . C . E2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 t = 2 0 0 ; // t i m e i n s e c

7 M = 1 1 1 . 8 3 ; // s i l v e r i n mg8 I = 0 . 5 ; // c u r r e n t i n A9 Z = ( M / ( I * t * 1 0 0 0 ) ) * 1 0 0 0 ; // e l e c t r oc h e m i c a le q u i v a l e n t

10 disp (Z , E . C . E , Z ( m g / C ) = )

Scilab code Exa 5.2 thickness of coper

1 / / Example 5 . 2 : t h i c k n e s s2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :

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6 Z = 0 . 3 2 9 * 1 0 ^ - 3 ; / / IN g /C

7 I = 1 ; // i n a mp er es8 t = 9 0 * 6 0 ; // i n s e c on ds9 M = Z * I * t ; / / i n g ra ms

10 A = 2 0 0 ; // a r ea i n c e n ti m e te s q ua r e11 S = 8 . 9 ; // d e n s i t y i n g / c c12 T = ( M ) / ( 2 * A * S ) ; // t h i c k n e s s i n cm13 disp (T , t h i c k n e s s o f c op pe r i n cm i s )


1 / /Example 5 . 3 // r e s i s t a n c e o f t he h e at e r e le me nt2 clc ;

3 clear ;

4 close ;

5 w = 1 5 ; // i n kg6 t 1 = 1 5 ; // i n d eg re e c e l s i u s7 t 2 = 1 0 0 ; // i n d eg re e c e l s i u s8 t = 2 5 ; // t im e i n m in ut es9 I = 1 0 ; / / i n a mpere

10 n = 8 5 ; // e f f i c i e n c y o f c o nv e r s i o n i n p e r c e nt ag e11 h o = w * ( t 2 - t 1 ) ; // o ut p ut h ea t r e q u i r e d i n k c al12 R = ( ( h o * 4 1 8 7 * 1 0 0 ) / ( I ^ 2 * t * 6 0 * n ) ) ; // r e s i s t a n c e i n ohms13 disp (R , r e s i s t a n c e i n ohms )

Scilab code Exa 5.4 potential difference

1 / /Example 5 . 4 // p o t e n t i a l d i f f e r e n c e a c r o s s t he

h e a t e r e l em e nt2 clc ;

3 clear ;

4 close ;

5 w = 2 0 ; // i n kg

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6 t 1 = 1 0 ; // i n d eg re e c e l s i u s

7 t 2 = 9 0 ; // i n d eg r e e c e l s i u s8 t = 2 * 3 6 0 0 + 1 9 * 6 0 + 3 4 ; // t i me i n s e c on ds9 I = 4 ; // i n a mp ere

10 n = 8 0 ; // e f f i c i e n c y o f c o nv e r s i o n i n p e r c e nt ag e11 h o = w * ( t 2 - t 1 ) ; // o ut p ut h ea t r e q u i r e d i n k c al12 V = ( ( h o * 4 1 8 7 * 1 0 0 ) / ( I * t * n ) ) ; // POTENTIAL DROP IN VOLTS13 disp (V , p o t e n t i a l drop a c r o s s h e at e r e le me nt i n

v o l t s i s )

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Chapter 6

magnetism and

electromagnetism

Scilab code Exa 6.1 field strength

1 / / Exam ple 6 . 1 / / f i e l d s t r e n g t h2 clc ;

3 clear ;

4 close ;

5 I = 1 . 5 ; / / i n a mp er es6 n = 5 0 ; / / t u r n s7 l = 0 . 2 5 ; // l e n g t h o f c o i l i n me t er8 H = ( I * n ) / l ; / / f i e l d s t r e n g t h i n a mp er et u r n s / m9 disp (H , f i e l d s t r e n g t h i n a mp er et ur ns/m)

Scilab code Exa 6.2 force

1 / / Example 6 . 2 // f o r c e2 clc ;

3 clear ;

4 close ;

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5 I = 7 0 ; / / i n a mp er es

6 B = 0 . 4 ; / / f l u s d e n s i t y i n Wb/m 27 n = 1 ; / / t u r n s8 F = B * n * I ; / / i n newto n9 disp (F , f o r c e i n n ew to ns i s )

Scilab code Exa 6.3 emf induced

1

2 / / E xam ple 6 . 3 / / emf i n d u ce d3 clc ;

4 clear ;

5 close ;

6 b = 2 ; // i n Wb/m27 l = 6 ; // i n cm8 s = 0 . 7 5 ; // i n m s9 a l p h a = 9 0 ; //

10 e m f = b * l * s * ( s i n d ( a l p h a ) ) ; //11 disp ( e m f , emf i nd uc ed i n v o l t s i s )

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Chapter 7

DC generators

Scilab code Exa 7.1.a emf induced

1 / / E xa mp le 7 . 1 . a : e . m. f 2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 p = 8 ; // number o f p o l e s

7 a = p ; // i n l ap w in di ng8 f i = 1 5 * 1 0 ^ - 3 ; // i n wb9 N = 5 0 0 ; / / r e v / min

10 Z = 8 0 0 ; / / number o f c o n d u c to r s on a rm at ur e11 e m f = ( f i * Z * N * p ) / ( 6 0 * a ) ; // when t he a rm at ur e i s l a p

wound12 disp ( e m f , e m f ( V ) = )

Scilab code Exa 7.1.b emf generated

1 / / Exam ple 7 . 1 . b : e .m . f i f t h e a r ma t ur e i s wave wound2 clc ;

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3 clear ;

4 close ;5 / / g i v e n d at a :6 p = 8 ; // number o f p o l e s7 a = 2 ; / / i n wave w in d in g8 f i = 1 5 * 1 0 ^ - 3 ; // i n wb9 N = 5 0 0 ; / / r e v / min

10 Z = 8 0 0 ; / / number o f c o n d u c to r s on a rm at ur e11 e m f = ( f i * Z * N * p ) / ( 6 0 * a ) ; // when t h e a rm at ur e i s wave

wound12 disp ( e m f , e m f ( V ) = )

Scilab code Exa 7.2.a total armature current

1 / / Example 7 . 2 . a : t o t a l a rm at ur e c u r r e n t2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 V t = 2 0 0 ; // t e r m i n a l v o l t a ge i n v o l t s

7 R s h = 1 0 0 ; // s h u n t f i e l d r e s i s t a n c e i n ohm8 R a = 0 . 1 ; // a rm at u re r e s i s t a n c e i n ohm9 l = 6 0 ; / / number o f l am ps

10 w = 4 0 ; // i n wat t11 t o t a l _ l = l * w ; // i n wat t12 I l = t o t a l _ l / V t ; // l oa d c u r r e nt13 I s h = V t / R s h ; / / s h un t f i e l d c u r r e n t14 I a = I l + I s h ;

15 disp ( I a , a r m a t u r e c u r r e n t , I a (A) = )

Scilab code Exa 7.2.b current per armature path

1 / / Example 7 . 2 . b : c u r r e n t p e r a rm at ur e p at h

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2 clc ;

3 clear ;4 close ;

5 / / g i v e n d at a :6 V t = 2 0 0 ; // t e r m i n a l v o l t a ge i n v o l t s7 R s h = 1 0 0 ; // s h u n t f i e l d r e s i s t a n c e i n ohm8 R a = 0 . 1 ; // a rm at u re r e s i s t a n c e i n ohm9 l = 6 0 ; / / number o f l am ps

10 w = 4 0 ; // i n wat t11 t o t a l _ l = l * w ; // i n wat t12 I l = t o t a l _ l / V t ; // l oa d c u r r e nt13 I s h = V t / R s h ; / / s h un t f i e l d c u r r e n t

14 I a = I l + I s h ;15 N = 4 ; // number o f p o l e s16 I = I a / N ;

17 disp (I , c u r r e n t p e r p at h i n a a rm at ur e , I (A) = )

Scilab code Exa 7.2.c emf generated

1 / / E xa mp le 7 . 2 . c : e mf

2 clc ;3 clear ;

4 close ;

5 / / g i v e n d at a :6 V t = 2 0 0 ; // t e r m i n a l v o l t a ge i n v o l t s7 R s h = 1 0 0 ; // s h u n t f i e l d r e s i s t a n c e i n ohm8 R a = 0 . 1 ; // a rm at u re r e s i s t a n c e i n ohm9 l = 6 0 ; / / number o f l am ps

10 w = 4 0 ; // i n wat t11 t o t a l _ l = l * w ; // i n wat t

12 I l = t o t a l _ l / V t ; // l oa d c u r r e nt13 I s h = V t / R s h ; / / s h un t f i e l d c u r r e n t14 I a = I l + I s h ;

15 N = 4 ; // number o f p o l e s16 I = I a / N ;

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17 V a = I a * R a ; // a r m at ur e v o l t a g e d ro p

18 V b = 1 + 1 ; // b r u s h c on t a c t dr op f o r 2 p a i r o f p o l es19 E = V t + V a + V b ;20 disp (E , emf , E ( v ) = )

Scilab code Exa 7.3.a terminal voltage

1 / / Example 7 . 3 . a : t e r m i n a l v o l t a g e2 clc ;

3 clear ;4 close ;

5 / / g i v e n d at a :6 W = 1 0 ; // o u tp u t o f t he g e n e ra t o r i n kw7 V = 2 5 0 ; // v o l t a g e i n v o l t s8 R = 0 . 0 7 ; / / i n ohm9 I l = ( W * 1 0 0 0 ) / V ; // l oa d c u r r e n t i n A

10 V f = I l * R ; // v o lt a g e dr op i n f e e de r11 V t = V + V f ;

12 disp ( V t , t e r m i n a l v o l t a g e , Vt (V) = )


1 / / E xa mp le 7 . 3 . b : e mf 2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 W = 1 0 ; // o u tp u t o f t he g e n e ra t o r i n kw

7 V = 2 5 0 ; // v o l t a g e i n v o l t s8 R = 0 . 0 7 ; / / i n ohm9 I l = ( W * 1 0 0 0 ) / V ; // l oa d c u r r e n t i n A

10 V f = I l * R ; // v o lt a g e dr op i n f e e de r11 V t = V + V f ; // t e rm i n al v o l t a g e

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12 R s h = 6 3 . 2 ; // s hu nt r e s i s t a n c e i n ohm

13 R a = 0 . 0 5 ; // a rm at ur e r e s i s t a n c e i n ohm14 V b = 2 ; // b ru sh c o n t ac t d ro p15 I s h = V t / R s h ;

16 I a = I l + I s h ;

17 V d = I a * R a ; // v o l t a g e dr op i n t he a rm at ur e18 E = V t + V d + V b ;

19 disp (E , e mf , E ( V ) = )

Scilab code Exa 7.4.a terminal voltage

1 / / Example 7 . 4 . a : t e r m i n a l v o l t a g e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 W = 2 0 0 0 0 ; // i n wat t7 V = 2 0 0 ; // i n v o l t s8 R = 0 . 0 8 ; / / i n ohm9 R s = 0 . 0 2 ; // s e r i e s f i e l d r e s i s t a n c e i n ohm

10 I = W / V ; // i n A11 V f = I * R ;

12 V s = I * R s ;

13 V 1 = V f + V s ; / / v o l t ag e dro p o f f e e d e r and s e r i e s f i e l d14 V g = V + V 1 ;

15 disp ( V g , t e r m i n a l v o l t a g e , Vg (V) = )


1 / / Exam ple 7 . 4 . b : emf g e n e r a t e d2 clc ;

3 clear ;

4 close ;

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5 / / g i v e n d at a :

6 W = 2 0 0 0 0 ; // i n wa tt7 V = 2 0 0 ; // i n v o l t s8 R = 0 . 0 8 ; / / i n ohm9 R s = 0 . 0 2 ; // s e r i e s f i e l d r e s i s t a n c e i n ohm

10 I = W / V ; // i n A11 R s h = 4 2 ; // s h u n t i e l d r e s i s t a n c e i n ohm12 R a = 0 . 0 4 ; // a r m a t u r e r e s i s t a n c e i n ohm13 V f = I * R ;

14 V s = I * R s ;

15 V 1 = V f + V s ; / / v o l t ag e dro p o f f e e d e r and s e r i e s f i e l d16 V g = V + V 1 ; // t e rm i n al v o l t a g e

17 I s h = V g / R s h ; / / s h un t f i e l d c u r r e n t18 I a = I + I s h ;

19 V d = I a * R a ;

20 e m f = V g + V d ;

21 disp ( e m f , e m f ( V ) = )

Scilab code Exa 7.4.c copper losses

1 / / Example 7 . 4 . c : c o pp e r l o s s e s2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 W = 2 0 0 0 0 ; / / e l e c t r i c a l o u t p u t i n w a t t7 V = 2 0 0 ; // i n v o l t s8 R = 0 . 0 8 ; / / i n ohm9 R s = 0 . 0 2 ; // s e r i e s f i e l d r e s i s t a n c e i n ohm

10 I = W / V ; // i n A

11 R s h = 4 2 ; // s h u n t i e l d r e s i s t a n c e i n ohm12 R a = 0 . 0 4 ; // a r m a t u r e r e s i s t a n c e i n ohm13 V f = I * R ;

14 V s = I * R s ;

15 V 1 = V f + V s ; / / v o l t ag e dro p o f f e e d e r and s e r i e s f i e l d

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16 V g = V + V 1 ; // t e rm i n al v o l t a g e

17 I s h = V g / R s h ; / / s h un t f i e l d c u r r e n t18 I a = I + I s h ;19 V d = I a * R a ;

20 e m f = V g + V d ;

21 E d = e m f * I a ; // i n wat t22 c o p p e r _ l o s s e s = E d - W ;

23 disp (copper_ losses , c o p p er l o s s e s ( Watt ) = )

Scilab code Exa 7.4.d Bhp metric of the primemover

1 / / Exam ple 7 . 4 . d : bhp m e t r i c o f t h e p ri me mo ve r2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 W = 2 0 0 0 0 ; / / e l e c t r i c a l o u t p u t i n w a t t7 V = 2 0 0 ; // i n v o l t s8 R = 0 . 0 8 ; / / i n ohm9 R s = 0 . 0 2 ; // s e r i e s f i e l d r e s i s t a n c e i n ohm

10 I = W / V ; // i n A11 R s h = 4 2 ; // s h u n t i e l d r e s i s t a n c e i n ohm12 R a = 0 . 0 4 ; // a r m a t u r e r e s i s t a n c e i n ohm13 i r o n _ l o s s e s = 3 0 9 . 5 ; / / i r o n a nd f r i c t i o n l o s s e s14 V f = I * R ;

15 V s = I * R s ;

16 V 1 = V f + V s ; / / v o l t ag e dro p o f f e e d e r and s e r i e s f i e l d17 V g = V + V 1 ; // t e rm i n al v o l t a g e18 I s h = V g / R s h ; / / s h un t f i e l d c u r r e n t19 I a = I + I s h ;

20 V d = I a * R a ;21 e m f = V g + V d ;


24 m e c h _ i n = W + c o p p e r _ l o s s e s + i r o n _ l o s s e s ;

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25 B h p = m e c h _ i n / 7 3 5 . 5 ;

26 disp ( B h p , bhp m e t r i c o f t h e p ri me mo ve r , Bhp = )

Scilab code Exa 7.4.e commercial efficiency

1

2 / / Exam ple 7 . 4 . d : bhp m e t r i c o f t h e p ri me mo ve r3 clc ;

4 clear ;

5 close ;6 / / g i v e n d at a :7 W = 2 0 0 0 0 ; / / e l e c t r i c a l o u t p u t i n w a t t8 V = 2 0 0 ; // i n v o l t s9 R = 0 . 0 8 ; / / i n ohm

10 R s = 0 . 0 2 ; // s e r i e s f i e l d r e s i s t a n c e i n ohm11 I = W / V ; // i n A12 R s h = 4 2 ; // s h u n t i e l d r e s i s t a n c e i n ohm13 R a = 0 . 0 4 ; // a r m a t u r e r e s i s t a n c e i n ohm14 i r o n _ l o s s e s = 3 0 9 . 5 ; / / i r o n a nd f r i c t i o n l o s s e s15 V f = I * R ;

16 V s = I * R s ;17 V 1 = V f + V s ; / / v o l t ag e dro p o f f e e d e r and s e r i e s f i e l d18 V g = V + V 1 ; // t e rm i n al v o l t a g e19 I s h = V g / R s h ; / / s h un t f i e l d c u r r e n t20 I a = I + I s h ;

21 V d = I a * R a ;

22 e m f = V g + V d ;


25 m e c h _ i n = W + c o p p e r _ l o s s e s + i r o n _ l o s s e s ; / / m e ch a n ic a l

p ow er i n o p u t26 B h p = m e c h _ i n / 7 3 5 . 5 ;27 e f f i c i e n c y = ( W / m e c h _ i n ) * 1 0 0 ;

28 disp (efficiency , e f f i c i e n c y (%) = )

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Scilab code Exa 7.5.a total armature current

1 / / Example 7 . 5 . a : t o t a l a rm at ur e c u r r e n t2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s7 i = 3 0 ; // c u r r e nt i n A8 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s9 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e

10 V = 4 4 0 ; // v o l t a g e i n V11 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t12 I a = I + I s h ;

13 disp ( I a , t o t a l a r ma t ur e c u r r e n t , I a (A) = )

Scilab code Exa 7.5.b current

1 / / Example 7 . 5 . b : c u r r e n t i n e ac h p at h2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s

10 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e11 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm12 V = 4 4 0 ; // v o l t a g e i n V13 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t14 I a = I + I s h ;

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15 I 1 = I a / n 1 ; // c u r r e nt i n e a ch path

16 disp ( I 1 , c u r r e n t i n e a ch p at h , I 1 (A) = )

Scilab code Exa 7.5.c emf generated

1 / / E xa mp le 7 . 5 . c : e . m. f 2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s

10 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e11 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm12 V = 4 4 0 ; // v o l t a g e i n V13 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t14 I a = I + I s h ;


16 V a = I a * R a ; // a r ma t ur e d ro p17 V b = 2 ; // we know , b ru sh c o n ta c t d ro ps18 E = V + V a + V b ;

19 disp (E , e mf , E ( V ) = )20 / / a ns we r i s wrong i n a book

Scilab code Exa 7.5.d power developed

1 / / E xa mp le 7 . 5 . d : e l e c t r i c a l p ow er d e v e l o p e d i n t h ea r m a t u r e

2 clc ;

3 clear ;

4 close ;

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5 / / g i v e n d at a :

6 n = 3 ; / / number o f m o to r s7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 B h p = 6 5 ; // i n hp

10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm13 V = 4 4 0 ; // v o l t a g e i n V14 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t15 I a = I + I s h ;


17 V a = I a * R a ; // a r ma t ur e d ro p18 V b = 2 ; // we know , b ru sh c o n ta c t d ro ps19 E = V + V a + V b ;

20 E _ p o w e r = E * I a ;

21 W = V * I ; // i n w att22 M _ p o w e r = B h p * 7 4 6 ; // assume Bhp=746 W23 disp (E_p ower , e l e c t r i c a l p o we r d e v e l o p e d i n w a t t =

)

24 / / a ns we r i s wrong i n a book

Scilab code Exa 7.5.e copper losses

1 / / Example 7 . 5 . e : c o pp e r l o s s e s2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s

7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 B h p = 6 5 ; // i n hp

10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e

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12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm


16 I 1 = I a / n 1 ; // c u r r e nt i n e a ch path17 V a = I a * R a ; // a r ma t ur e d ro p18 V b = 2 ; // we know , b ru sh c o n ta c t d ro ps19 E = V + V a + V b ;

20 E _ p o w e r = E * I a ;

21 W = V * I ; // i n w att22 M _ p o w e r = B h p * 7 4 6 ; // assume Bhp=746 W23 Copper_l osses =E_power -W;

24 disp (Copper_ losses , c o pp er l o s s e s (W) = )

Scilab code Exa 7.5.f stray losses

1 // Example 7 . 5 . f : s t r a y l o s s e s2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 B h p = 6 5 ; // i n hp

10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm13 V = 4 4 0 ; // v o l t a g e i n V14 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t

15 I a = I + I s h ;16 I 1 = I a / n 1 ; // c u r r e nt i n e a ch path17 V a = I a * R a ; // a r ma t ur e d ro p18 V b = 2 ; // we know , b ru sh c o n ta c t d ro ps19 E = V + V a + V b ;

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20 E _ p o w e r = E * I a ;


24 S_loses =M_power -E_p ower;

25 disp (S_l oses , s t r a y l o s s e s (W) = )

Scilab code Exa 7.5.g.1 electrical efficiency

1 / / E xa mp le 7 . 5 . g . i : e l e c t r i c a l e f f i c i e n c y2 clc ;

3 clear ;

4 close ;


10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e

12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm13 V = 4 4 0 ; // v o l t a g e i n V14 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t15 I a = I + I s h ;


20 E _ p o w e r = E * I a ;

21 W = V * I ; // i n w att

22 M _ p o w e r = B h p * 7 4 6 ; // assume Bhp=746 W23 Copper_l osses =E_power -W;24 S_loses =M_power -E_p ower;

25 e t a _ e = ( W / E _ p o w e r ) * 1 0 0 ;

26 disp ( e t a _ e , e l e c t r i c a l e f f i c i e n c y , e t a e (%) = )

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Scilab code Exa 7.5.g.2 commercial efficiency

1 / / Example 7 . 5 . g . i : c o mm e rc i al e f f i c i e n c y2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 n = 3 ; / / number o f m o to r s

7 n 1 = 4 ; // number o f p a r a l l e l pat h i n w in di ng8 i = 3 0 ; // c u r r e nt i n A9 B h p = 6 5 ; // i n hp

10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm13 V = 4 4 0 ; // v o l t a g e i n V14 I s h = V / R s h ; / / s h un t f i e l d c u r r e n t15 I a = I + I s h ;


20 E _ p o w e r = E * I a ;



25 e t a _ c = ( W / M _ p o w e r ) * 1 0 0 ;

26 disp ( e t a _ c , c o m me rc i al e f f i c i e n c y , e t a c (%) = )

Scilab code Exa 7.5.g.3 mechanical efficiency

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1 / / E xa mp le 7 . 5 . g . i : e l e c t r i c a l e f f i c i e n c y

2 clc ;3 clear ;

4 close ;


10 I = i * n ; // c u r r en t t ak en by t h r e e m ot or s11 R s h = 4 4 ; // s hu nt f i e l d r e s i s t a n c e12 R a = 0 . 0 8 ; // a rm at ur e r e s i s t a n c e i n ohm



20 E _ p o w e r = E * I a ;



25 e t a _ m = ( E _ p o w e r / M _ p o w e r ) * 1 0 0 ;

26 disp ( e t a _ m , m e c h a n ic a l e f f i c i e n c y , e ta m (%) = )

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Chapter 8

DC motors

Scilab code Exa 8.1 speed

1 / / Exam ple 8 . 1 / / s p e ed2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 p i = 2 2 / 7 ;

7 s = 2 2 ; // s h a f t o f t h e m otor i n hp8 T s h = 2 1 0 ; // t or ue i n hp9 N = ( s * 6 0 * 7 4 6 ) / ( 2 * p i * T s h ) ;

10 disp (N , s p e e d , N ( r p m ) = )

Scilab code Exa 8.2.a Bhp

1 / / E xa mp le 8 . 2 . a : bhp2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :

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6 V = 2 3 0 ; // v o l t a g e i n v o l t s

7 I = 7 2 ; // c u r r e n t i n A8 W = V * I ;9 s = 9 6 8 ; // s t r a y l o s s e s

10 R s h = 1 1 5 ; // s hu nt f i e l d r e s i s t a n c e i n ohm11 R a = 0 . 5 ; // a rm at ur e r e s i s t a n c e i n ohm12 I s h = V / R s h ; // s hu nt f i e l d r e s i s t a n c e13 I a = I - I s h ;

14 E b = V - ( I a * R a ) ; // back emf i n v o l t s15 D p d = E b * I a ; // d r i v i n g power d e ve l op e d16 M p o = D p d - s ;

17 b h p = M p o / 7 4 6 ;

18 disp ( b h p , b h p = )

Scilab code Exa 8.2.b copper losses

1 / / Example 8 . 2 . b : c o pp e r l o s s e s2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 V = 2 3 0 ; // v o l t a g e i n v o l t s7 I = 7 2 ; // c u r r e n t i n A8 W = V * I ;

9 s = 9 6 8 ; // s t r a y l o s s e s10 R s h = 1 1 5 ; // s hu nt f i e l d r e s i s t a n c e i n ohm11 R a = 0 . 5 ; // a rm at ur e r e s i s t a n c e i n ohm12 I s h = V / R s h ; // s hu nt f i e l d r e s i s t a n c e13 I a = I - I s h ;

14 E b = V - ( I a * R a ) ; // back emf i n v o l t s

15 D p d = E b * I a ; // d r i v i n g power d e ve l op e d16 M p o = D p d - s ;17 b h p = M p o / 7 4 6 ;

18 c _ l o s s e s = W - D p d ;

19 disp (c_ losses , c o p p er l o s s e s (W) = )

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Scilab code Exa 8.2.c armature torque

1 / / Exam ple 8 . 2 . c : a r ma t ur e t o r q u e2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 N = 9 5 5 ; / / i n r . p . m

7 V = 2 3 0 ; // v o l t a g e i n v o l t s8 I = 7 2 ; // c u r r e n t i n A9 W = V * I ;



18 b h p = M p o / 7 4 6 ;

19 c _ l o s s e s = W - D p d ;

20 T a = ( 9 . 5 5 * E b * I a ) / N ;

21 disp ( T a , t o r q u e a r ma t ur e , Ta ( Nm ) = )

Scilab code Exa 8.2.d shaft torque

1 / / Example 8 . 2 . d : s h a f t t o r q ue2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :

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6 p i = 2 2 / 7 ;

7 N = 9 5 5 ; / / i n r . p . m8 V = 2 3 0 ; // v o l t a g e i n v o l t s9 I = 7 2 ; // c u r r e n t i n A

10 W = V * I ;


16 E b = V - ( I a * R a ) ; // back emf i n v o l t s17 D p d = E b * I a ; // d r i v i n g power d e ve l op e d

18 M p o = D p d - s ;19 b h p = M p o / 7 4 6 ;

20 c _ l o s s e s = W - D p d ;

21 T a = ( 9 . 5 5 * E b * I a ) / N ;

22 T s h = ( b h p * 6 0 * 7 4 6 ) / ( 2 * p i * N ) ;

23 disp ( T s h , s h a f t t o r q u e , Tsh ( Nm ) = )

Scilab code Exa 8.2.e lost torque

1 / / Example 8 . 2 . e : l o s t t o r q ue2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 p i = 2 2 / 7 ;

7 N = 9 5 5 ; / / i n r . p . m8 V = 2 3 0 ; // v o l t a g e i n v o l t s9 I = 7 2 ; // c u r r e n t i n A

10 W = V * I ;11 s = 9 6 8 ; // s t r a y l o s s e s12 R s h = 1 1 5 ; // s hu nt f i e l d r e s i s t a n c e i n ohm13 R a = 0 . 5 ; // a rm at ur e r e s i s t a n c e i n ohm14 I s h = V / R s h ; // s hu nt f i e l d r e s i s t a n c e

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15 I a = I - I s h ;


19 b h p = M p o / 7 4 6 ;

20 c _ l o s s e s = W - D p d ;

21 T a = ( 9 . 5 5 * E b * I a ) / N ;

22 T s h = ( b h p * 6 0 * 7 4 6 ) / ( 2 * p i * N ) ;

23 T l = T a - T s h ;

24 disp ( T l , l o s t t o r qu e , T l ( Nm ) = )

Scilab code Exa 8.2.f commercial efficiency

1 // Example 8 . 2 . f : c om me rc ia l e f f i c i e n c y2 clc ;

3 clear ;

4 close ;

5 / / g i v e n d at a :6 p i = 2 2 / 7 ;

7 N = 9 5 5 ; / / i n r . p . m

8 V = 2 3 0 ; // v o l t a g e i n v o l t s9 I = 7 2 ; // c u r r e n t i n A

10 W = V * I ;


16 E b = V - ( I a * R a ) ; // back emf i n v o l t s17 D p d = E b * I a ; // d r i v i n g power d e ve l op e d

18 M p o = D p d - s ;19 b h p = M p o / 7 4 6 ;

20 c _ l o s s e s = W - D p d ;

21 T a = ( 9 . 5 5 * E b * I a ) / N ;

22 T s h = ( b h p * 6 0 * 7 4 6 ) / ( 2 * p i * N ) ;

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23 T l = T a - T s h ;

24 e t a = ( M p o / W ) * 1 0 0 ;25 disp ( e t a , c o m me rc i al e f f i c i o e n c y , e t a (%) = )

Scilab code Exa 8.3 speed

1 / / Exam ple 8 . 3 / / s p e ed2 clc ;

3 clear ;

4 close ;5 V = 2 3 0 ; // i n v o l t s6 I = 5 ; / / i n a mp er es7 r p m = 9 1 4 ; / / t u r n s8 r a = 0 . 5 ; // r e s i s t a n c e o f a rm at u re i n ihms9 r s h = 1 1 5 ; / / s h u n t f i e l d i n ohms

10 I l = 3 0 ; // i n a mp er es11 a r = 1 0 ; // i n p e rc e n t12 I s h = V / r s h ; / / i n a mp er es13 a n l = I - I s h ; // a r ma tu re c u r r e nt i n a mp er es a t no l o ad14 a l = I l - I s h ; // a r ma tu re c u r r e n t i n a mp ere s a t l o ad

15 E b 1 = ( V - a n l * r a ) ; // b ack emf a t no l o ad16 E b 2 = ( V - a l * r a ) ; // b ack emf a t l o ad17 p h 1 = 1 0 0 ; //18 p h 2 = 9 0 ; //19 N s = ( r p m * E b 2 * p h 1 ) / ( E b 1 * p h 2 ) ; / / s p e e d when l o a d e d i n

rpm20 disp ( N s , s p e e d when l o a d e d i n rpm )

Scilab code Exa 8.4.a stray losses

1 / / Example 8 . 4 . a // s t r a y l o s s e s2 clc ;

3 clear ;

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4 close ;

5 I l = 8 3 ; // WHEN LOADED IN AMPERES6 V = 1 1 0 ; // i n v o l t s7 I = 5 ; // i n a mp ere s w it ho ut l o ad8 r a = 0 . 5 ; // a r ma tu re r e s i s t a n c e i n ohms9 r s h = 1 1 0 ; / / s h u n t f i e l d i n ohms

10 I s h = V / r s h ; / / i n a mpere11 a n l = I - I s h ; // a r ma tu re c u r r e nt i n a mp er es a t no l o ad12 a l = I l - I s h ; // a r ma tu re c u r r e n t i n a mp ere s a t l o ad13 E b 1 = ( V - a n l * r a ) ; // b ack emf a t no l o ad14 E b 2 = ( V - a l * r a ) ; // b ack emf a t l o ad15 D p = E b 1 * a n l ; // d r i v i n g power a t no l o ad i n w att

16 D p l = E b 2 * a l ; // d r i v i n g power a t l o ad i n wa tt17 m o = D p l - D p ; // o u t o f motor i n wa tt18 disp ( D p , s t ra y l o s s e s i n wat t )

Scilab code Exa 8.4.b horsepower of the motor

1 / / Exam ple 8 . 4 . b / / h o r s e p ow er2 clc ;

3 clear ;4 close ;


10 I s h = V / r s h ; / / i n a mpere11 a n l = I - I s h ; // a r ma tu re c u r r e nt i n a mp er es a t no l o ad12 a l = I l - I s h ; // a r ma tu re c u r r e n t i n a mp ere s a t l o ad

13 E b 1 = ( V - a n l * r a ) ; // b ack emf a t no l o ad14 E b 2 = ( V - a l * r a ) ; // b ack emf a t l o ad15 D p = E b 1 * a n l ; // d r i v i n g power a t no l o ad i n w att16 D p l = E b 2 * a l ; // d r i v i n g power a t l o ad i n wa tt17 m o = D p l - D p ; // o u t o f motor i n wa tt

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18 b h p = m o / 7 4 6 ; / / h o r s e p ow er

19 disp ( b h p , h o r s e po wer i n a mp ere i s )

Scilab code Exa 8.4.c efficiency

1 // Example 8 . 4 . c // e f f i c i e n c y2 clc ;

3 clear ;

4 close ;


10 I s h = V / r s h ; / / i n a mpere11 a n l = I - I s h ; // a r ma tu re c u r r e nt i n a mp er es a t no l o ad12 a l = I l - I s h ; // a r ma tu re c u r r e n t i n a mp ere s a t l o ad13 E b 1 = ( V - a n l * r a ) ; // b ack emf a t no l o ad14 E b 2 = ( V - a l * r a ) ; // b ack emf a t l o ad15 D p = E b 1 * a n l ; // d r i v i n g power a t no l o ad i n w att

16 D p l = E b 2 * a l ; // d r i v i n g power a t l o ad i n wa tt17 m o = D p l - D p ; // o u t o f motor i n wa tt18 b h p = m o / 7 4 6 ; / / h o r s e p ow er19 m i = V * a l ; / / i n p u t p ow er i n w at t20 n = ( m o / m i ) * 1 0 0 ; // e f f i c i e n c y i n p e r ce nt a g e21 disp (n , e f f i c i e n c y o f motor when i t i s work on f u l l

, l oa d i n p e rc e nt a ge i s )22 / / a ns we r i s wrong i n t he t ex t bo o k

Scilab code Exa 8.5.a back emf

1 / / Exam ple 8 . 5 . a / / b ac k emf 2 clc ;

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3 clear ;

4 close ;5 V = 2 3 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es7 r p m = 9 5 5 ; / / t u r n s8 r a = 0 . 2 ; // r e s i s t a n c e o f a rm at u re i n ihms9 r s h = 0 . 1 5 ; / / s h u n t f i e l d i n ohms

10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s13 disp ( E b , ba ck emf i n v o l t s )

Scilab code Exa 8.5.b copper losses

1 // Example 8 . 5 . b // c op pe r l o s s e s2 clc ;

3 clear ;

4 close ;

5 V = 2 3 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es

7 r p m = 9 5 5 ; / / t u r n s8 r a = 0 . 2 ; // r e s i s t a n c e o f a rm at u re i n ihms9 r s h = 0 . 1 5 ; / / s h u n t f i e l d i n ohms

10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s13 D p = E b * I ; // d r i v i n g p ower i n w a tt s14 m i = V * I ; / / i n p u t po we r i n w a tt s15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s16 disp ( C l , c op pe r l o s s e s i n w a tt s )

Scilab code Exa 8.5.c Bhp

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1 / / E xa mp le 8 . 5 . c / / h o r s e p ow er

2 clc ;3 clear ;

4 close ;

5 V = 2 3 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es7 r p m = 9 5 5 ; / / t u r n s8 r a = 0 . 2 ; // r e s i s t a n c e o f a rm at u re i n ihms9 r s h = 0 . 1 5 ; / / s h u n t f i e l d i n ohms

10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s

13 D p = E b * I ; // d r i v i n g p ower i n w a tt s14 m i = V * I ; / / i n p u t po we r i n w a tt s15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s16 m o = D p - s l ; / / o ut p ut o f m oto r17 b h p = m o / 7 4 6 ; // h o r se power i n bhp18 disp ( b h p , h o r se power i s )

Scilab code Exa 8.5.d total torque

1 / / Example 8 . 5 . d / / t o t a l t o r q ue2 clc ;

3 clear ;

4 close ;


10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s13 D p = E b * I ; // d r i v i n g p ower i n w a tt s14 m i = V * I ; / / i n p u t po we r i n w a tt s

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15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s

16 m o = D p - s l ; / / o ut p ut o f m oto r17 b h p = m o / 7 4 6 ; // h o r se power i n bhp18 T a = ( 9 . 5 5 * E b * I ) / r p m ; // t o t a l t or qu e i n Nm19 disp ( T a , t o t a l t or qu e i n Nm)

Scilab code Exa 8.5.e shaft torque

1 / / Example 8 . 5 . e / / s h a f t t o r q ue

2 clc ;3 clear ;

4 close ;


10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s

13 D p = E b * I ; // d r i v i n g p ower i n w a tt s14 m i = V * I ; / / i n p u t po we r i n w a tt s15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s16 m o = D p - s l ; / / o ut p ut o f m oto r17 b h p = m o / 7 4 6 ; // h o r se power i n bhp18 T a = ( 9 . 5 5 * E b * I ) / r p m ; // t o t a l t or qu e i n Nm19 T s = ( b h p * 6 0 * 7 4 6 ) / ( 2 * % p i * r p m ) ; // s h a f t t or qu e i n Nm20 disp ( T s , s h a f t t or qu e i n Nm)

Scilab code Exa 8.5.f lost torque

1 / / Example 8 . 5 . f / / l o s t t o r q ue2 clc ;

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3 clear ;

4 close ;5 V = 2 3 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es7 r p m = 9 5 5 ; / / t u r n s8 r a = 0 . 2 ; // r e s i s t a n c e o f a rm at u re i n ihms9 r s h = 0 . 1 5 ; / / s h u n t f i e l d i n ohms

10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s13 D p = E b * I ; // d r i v i n g p ower i n w a tt s14 m i = V * I ; / / i n p u t po we r i n w a tt s

15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s16 m o = D p - s l ; / / o ut p ut o f m oto r17 b h p = m o / 7 4 6 ; // h o r se power i n bhp18 T a = ( 9 . 5 5 * E b * I ) / r p m ; // t o t a l t or qu e i n Nm19 T s = ( b h p * 6 0 * 7 4 6 ) / ( 2 * % p i * r p m ) ; // s h a f t t or qu e i n Nm20 T l = T a - T s ; // l o s t t or qu e i n Nm21 disp ( T l , l o s t t or qu e i n Nm)

Scilab code Exa 8.5.g commercial efficiency

1 // Example 8 . 5 . g // c o mm er ci al e f f i c i e n c y2 clc ;

3 clear ;

4 close ;

5 V = 2 3 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es7 r p m = 9 5 5 ; / / t u r n s8 r a = 0 . 2 ; // r e s i s t a n c e o f a rm at u re i n ihms

9 r s h = 0 . 1 5 ; / / s h u n t f i e l d i n ohms10 s l = 6 0 4 ; // s t ra y l o s s e s i n w a tt s11 R m = r a + r s h ; / / i n ohms12 E b = ( V - I * R m ) ; // back emf i n v o l t s13 D p = E b * I ; // d r i v i n g p ower i n w a tt s

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14 m i = V * I ; / / i n p u t po we r i n w a tt s

15 C l = m i - D p ; // c o pp er l o s s e s i n w at t s16 m o = D p - s l ; / / o ut p ut o f m oto r17 b h p = m o / 7 4 6 ; // h o r se power i n bhp18 T a = ( 9 . 5 5 * E b * I ) / r p m ; // t o t a l t or qu e i n Nm19 T s = ( b h p * 6 0 * 7 4 6 ) / ( 2 * % p i * r p m ) ; // s h a f t t or qu e i n Nm20 T l = T a - T s ; // l o s t t or qu e i n Nm21 n c = ( m o / m i ) * 1 0 0 ; // c om me rc ia l e f f i c i e n c y i n p e rc e n t ge22 disp ( n c , c om me rc ia l e f f i c i e n c y i n p e rc e nt g e )

Scilab code Exa 8.6 current taken

1 / / Exam ple 8 . 6 / / c u r r e n t2 clc ;

3 clear ;

4 close ;

5 V = 2 2 0 ; // i n v o l t s6 I = 6 0 ; / / i n a mp er es7 r p m = 7 2 8 ; / / t u r n s8 T s = 1 5 0 ; // s h a f t t or qu e i n Nm

9 n c = 8 0 ; // c o mm er ci al e f f i c i e n c y i n p e rc e nt g e10 I = ( ( T s * 2 *

Basic Electrical Engineering_P. S. Dhogal

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Transcript of Basic Electrical Engineering_P. S. Dhogal