From 476705d693c7122d34f9b049fa79b935405c9b49 Mon Sep 17 00:00:00 2001
From: prashantsinalkar
Date: Tue, 14 Apr 2020 10:19:27 +0530
Subject: Initial commit

---
 ...Thyristors_Principles_and_Characteristics.ipynb | 1400 ++++++++++++++++++++
 .../2-Phase_Controlled_Rectifiers.ipynb            |  997 ++++++++++++++
 .../3-Inverters.ipynb                              |  344 +++++
 .../4-Choppers.ipynb                               |  705 ++++++++++
 .../6-Control_of_DC_drives.ipynb                   |  161 +++
 5 files changed, 3607 insertions(+)
 create mode 100644 Introduction_to_Electric_Drives_by_V_Singhal/1-Thyristors_Principles_and_Characteristics.ipynb
 create mode 100644 Introduction_to_Electric_Drives_by_V_Singhal/2-Phase_Controlled_Rectifiers.ipynb
 create mode 100644 Introduction_to_Electric_Drives_by_V_Singhal/3-Inverters.ipynb
 create mode 100644 Introduction_to_Electric_Drives_by_V_Singhal/4-Choppers.ipynb
 create mode 100644 Introduction_to_Electric_Drives_by_V_Singhal/6-Control_of_DC_drives.ipynb

(limited to 'Introduction_to_Electric_Drives_by_V_Singhal')

diff --git a/Introduction_to_Electric_Drives_by_V_Singhal/1-Thyristors_Principles_and_Characteristics.ipynb b/Introduction_to_Electric_Drives_by_V_Singhal/1-Thyristors_Principles_and_Characteristics.ipynb
new file mode 100644
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+++ b/Introduction_to_Electric_Drives_by_V_Singhal/1-Thyristors_Principles_and_Characteristics.ipynb
@@ -0,0 +1,1400 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 1: Thyristors Principles and Characteristics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.12: RMS_current_and_form_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_12\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"I=120;//A\n",
+"Gamma=180;//degree\n",
+"RMS_current=I*sqrt(Gamma/360);//A\n",
+"AVG_current=I*(Gamma/360);//A\n",
+"FormFactor=RMS_current/AVG_current;//no unit\n",
+"disp(RMS_current,'rms current (in A) : ');\n",
+"disp(FormFactor,'Form Factor : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.13: Power_supplied.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_13\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=130;//V\n",
+"R=100;//ohm\n",
+"theta1=60;//degree\n",
+"theta2=45;//degree\n",
+"v=sqrt(2)*V;//\n",
+"Irms=sqrt(1/2/%pi*integrate('(3.25*sin(omega_t))^2','omega_t',theta1*%pi/180,%pi));//A\n",
+"P=Irms^2*R;//W\n",
+"disp(P,'(a) Power supplied to load (in W) : ');\n",
+"Irms=sqrt(1/2/%pi*integrate('(3.25*sin(omega_t))^2','omega_t',theta2*%pi/180,%pi));//A\n",
+"P=Irms^2*R;//W\n",
+"disp(P,'(a) Power supplied to load (in W) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.14: Average_power_loss.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_14\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Iavg=200;//A\n",
+"period1=2*%pi;\n",
+"period2=%pi;\n",
+"Vth1=1.8;//V\n",
+"I1=200;//A\n",
+"Vth2=1.9;//V\n",
+"I2=400;//A\n",
+"//part (a)\n",
+"Ploss1=I1*Vth1*period1/2/%pi;//W\n",
+"disp(Ploss1,'(a) Average power loss (in W) : ');\n",
+"Ploss2=I2*Vth2*period2/2/%pi;//W\n",
+"disp(Ploss2,'(b) Average power loss (in W) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.15: Average_on_state_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_15\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Irms=40;//A\n",
+"f=50;//Hz\n",
+"period1=170;//degree\n",
+"period2=100;//degree\n",
+"period3=40;//degree\n",
+"//part (a)\n",
+"alfa1=%pi-period1*%pi/180;//degree\n",
+"Irms_by_Im=sqrt(1/2/%pi*((%pi-alfa1)/2+sin(2*alfa1)/4));\n",
+"Im=Irms/Irms_by_Im;//A\n",
+"Iav1=Im/2/%pi*(1+cos(alfa1));//A\n",
+"disp(Iav1,'(a) Average current (in A) : ');\n",
+"//part (b)\n",
+"alfa2=%pi-period2*%pi/180;//degree\n",
+"Irms_by_Im=sqrt(1/2/%pi*((%pi-alfa2)/2+sin(2*alfa2)/4));\n",
+"Im=Irms/Irms_by_Im;//A\n",
+"Iav2=Im/2/%pi*(1+cos(alfa2));//A\n",
+"disp(Iav2,'(b) Average current (in A) : ');\n",
+"//part (c)\n",
+"alfa3=%pi-period3*%pi/180;//radian\n",
+"Irms_by_Im=sqrt(1/2/%pi*((%pi-alfa3)/2+sin(2*alfa3)/4));\n",
+"Im=Irms/Irms_by_Im;//A\n",
+"Iav3=Im/2/%pi*(1+cos(alfa3));//A\n",
+"disp(Iav3,'(c) Average current (in A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.16: Mean_power_dissipation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_16\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"//VT=0.9+0.02*IT;//V\n",
+"//part (a)\n",
+"IT=20;//A\n",
+"VT=0.9+0.02*IT;//V\n",
+"Pdiss=VT*IT;//W\n",
+"disp(Pdiss,'(a) Mean power dissipation (in W) : ');\n",
+"//part (b)\n",
+"IT_mean=20;//A\n",
+"IT_peak=20*%pi;//A\n",
+"Pdiss=1/2/%pi*integrate('(0.9+0.02*IT_peak*sin(theta))*(IT_peak*sin(theta))','theta',0,%pi);//W\n",
+"disp(Pdiss,'(b) Mean power dissipation (in W) : ');\n",
+"//part (c)\n",
+"IT=20;//A//for half cycle\n",
+"VT=0.9+0.02*IT;//V\n",
+"Pdiss=VT*IT/2;//W\n",
+"disp(Pdiss,'(c) Power dissipation occur only during half cycle. Mean power dissipation (W)');\n",
+"//part (d)\n",
+"IT=20;//A//for half cycle\n",
+"VT=0.9+0.02*IT;//V\n",
+"Pdiss=VT*IT/3;//W\n",
+"disp(Pdiss,'(d) Power dissipation occur only during 1/3rd period in a cycle. Mean power dissipation (W)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.17: Current_rating_and_I2t_rating.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_17\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"Isub=2000;//A\n",
+"f=50;//Hz\n",
+"t=10*10^-3;//s\n",
+"T=2*t;//s//duration of half cycle\n",
+"I=sqrt(Isub^2*t/T);//A\n",
+"I2t=I^2*t;//A^2 seconds\n",
+"disp(I2t,'I^2*t rating in A^2-seconds ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.18: Series_resistance_and_average_gate_power_loss.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_18\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"Vgate=12;//V\n",
+"t=60*10^-6;//s\n",
+"cycle=0.3;\n",
+"P_peak=6;//W\n",
+"//part (a)\n",
+"//P_peak=Vg*Ig leads to 9*Ig^2+Ig-P_peak=0\n",
+"X=[9 1 -6];//polynomial\n",
+"Ig=roots(X);//A\n",
+"Ig=Ig(2);//A(taking +ve value)\n",
+"Vg=1+9*Ig\n",
+"Rg=(Vgate-Vg)/Ig;//ohm\n",
+"disp(Rg,'Series resistance Rg in ohm');\n",
+"PavgLoss=P_peak*cycle;//W\n",
+"disp(PavgLoss,'Average power loss in W ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.19: Source_Resistance_Trigger_Current_and_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_19\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"Vs=12;//V\n",
+"P=0.3;//W\n",
+"Rs=100;//ohm//as slope is -100V/A\n",
+"//Vs=Vg+Ig*Rg leads to Rs*Ig^2-Vs*Ig+P=0\n",
+"X=[Rs -Vs P];//polynomial\n",
+"Ig=roots(X);//A\n",
+"Ig=Ig(2);//A(taking one value)\n",
+"disp(Rs,'Source resistance, Rs in ohm ');\n",
+"disp(Ig*1000,'Trigger current in mA ');\n",
+"Vg=P/Ig;//V\n",
+"disp(Vg,'Voltage Vg in V ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.1: Anode_Current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_1\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"alfa1=0.35;\n",
+"alfa2=0.4;\n",
+"IG=40*10^-3;//A\n",
+"\n",
+"//Solution :\n",
+"IA=alfa2*IG/(1-(alfa1+alfa2));//A\n",
+"disp(IA,'Anode current in A : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.20: Find_Rs_R1_and_R2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_20\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"V=800;//V\n",
+"I=110;//A\n",
+"Es=12;//V\n",
+"Im=250;//mA\n",
+"Ish=600;//mA\n",
+"VG=2.4;//V\n",
+"IG=50;//mA\n",
+"IGm=100;//mA\n",
+"VGm=3;//V\n",
+"Rs=Es/(Ish*10^-3);//ohm\n",
+"disp(Rs,'Value of Rs in ohm ');\n",
+"R1=Es/(Im*10^-3)-Rs;//ohm(Assumed R2 is not connected)\n",
+"//Rs_plus_R1>=Es/(IGm*10^-3);//ohm\n",
+"Rs_plus_R1=Es/(IGm*10^-3);//ohm\n",
+"R1_Lower=Rs_plus_R1-Rs;//ohm\n",
+"//Rs_plus_R1<=(Es-VG)/(IGm*10^-3);//ohm\n",
+"Rs_plus_R1=(Es-VG)/(IG*10^-3);//ohm\n",
+"R1_Upper=Rs_plus_R1-Rs;//ohm\n",
+"disp('R1 must be more than '+string(R1_Lower)+' ohm and less than '+string(R1_Upper)+' ohm.')\n",
+"disp('Let R1 is 125 ohm.');\n",
+"R1=125;//ohm\n",
+"//R2*Es/(R1+R2+Rs)<=VGm\n",
+"R2=(VGm*R1+VGm*Rs)/(Es-VGm);//ohm\n",
+"disp('R2<='+string(R2)+' ohm ')\n",
+"disp('Let R2 is 48 ohm.');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.21: Finf_thermal_resistance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_21\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"l=0.2;//m\n",
+"w=0.01;//m\n",
+"d=0.01;//m\n",
+"P=3;//W\n",
+"Tc=220;//W/m/degreeC\n",
+"T1=30;//degreeC\n",
+"theta=l/Tc/w/d;//degreeC/W\n",
+"T2=P*theta+T1;//degreeC\n",
+"disp(T2,'Temperature of the surface in degree C ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.22: Find_maximum_losses.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_22\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"l=2/1000;//m\n",
+"A=12/10000;//m^2\n",
+"T21=4;//degreeC(T2-T1)\n",
+"Tc=220;//W/m/degreeC\n",
+"theta=l/Tc/A;//degreeC/W\n",
+"Losses=T21/theta;//W\n",
+"disp(Losses,'Maximum losses in W ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.23: Thermal_resistance_of_heat_sink.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_23\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"P=30;//W\n",
+"T1=125;//degreeC\n",
+"T2=50;//degreeC\n",
+"theta=1;//degree C/W\n",
+"theta_mica=0.3;//degree C/W\n",
+"Rth_total=(T1-T2)/P;//degree C/W\n",
+"Rth_heat_sink=Rth_total-theta-theta_mica;//degree C/W\n",
+"disp(Rth_heat_sink,'Thermal resistance of heat sink in degree C/W ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.24: Find_Junction_temperature.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_25\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"T1=120;//degreeC(Junction Temperature)\n",
+"T2=35;//degreeC(Ambient Temperature)\n",
+"P=40;//W\n",
+"theta_dash=0.8;//degree C/W(junction to heat sink)\n",
+"theta=(T1-T2)/P;//degree C/W\n",
+"disp(theta-theta_dash,'Resistance of heat sink in degree C/W');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.25: Maximum_thermal_resiatance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_25\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"T1=120;//degreeC(Junction Temperature)\n",
+"T2=35;//degreeC(Ambient Temperature)\n",
+"P=40;//W\n",
+"theta_dash=0.8;//degree C/W(junction to heat sink)\n",
+"theta=(T1-T2)/P;//degree C/W\n",
+"disp(theta-theta_dash,'Resistance of heat sink in degree C/W');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.26: Average_power_loss_and_increase_in_rating.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_26\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Tj=125;//degreeC\n",
+"Ts=80;//degreeC\n",
+"theta_jc=0.7;//degree C/W\n",
+"theta_cs=0.4;//degree C/W\n",
+"//part (a)\n",
+"Pav1=(Tj-Ts)/(theta_jc+theta_cs);//W\n",
+"disp(Pav1,'(a) Average power loss in W')\n",
+"//part (b)\n",
+"Ts=50;//degreeC\n",
+"Pav2=(Tj-Ts)/(theta_jc+theta_cs);//W\n",
+"disp(Pav2,'(b) Permisible average power loss in W')\n",
+"rating_increase=(sqrt(Pav2)-sqrt(Pav1))/sqrt(Pav1)*100;//%\n",
+"disp(rating_increase,'Percentage increase in rating')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.27: Minimum_and_maximum_firing_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_27\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"vc=25;//V\n",
+"C=0.6*10^-6;//F\n",
+"R=2000:20000;//ohm\n",
+"Xc=1/(2*%pi*f*C);//ohm\n",
+"//When R=2000 ohm\n",
+"Z=min(R)-%i*Xc;//ohm\n",
+"I=Vs/Z;//A\n",
+"Vc=-%i*I*Xc;//V\n",
+"//vc=sqrt(2)*abs(Vc)*sind(omega_t+atand(imag(Vc),real(Vc)))\n",
+"omega_t=asind(vc/sqrt(2)/abs(Vc))-atand(imag(Vc),real(Vc));//degree\n",
+"alfa1=omega_t;//degree\n",
+"\n",
+"//When R=20000 ohm\n",
+"Z=max(R)-%i*Xc;//ohm\n",
+"I=Vs/Z;//A\n",
+"Vc=-%i*I*Xc;//V\n",
+"//vc=sqrt(2)*abs(Vc)*sind(omega_t+atand(imag(Vc),real(Vc)))\n",
+"omega_t=asind(vc/sqrt(2)/abs(Vc))-atand(imag(Vc),real(Vc));//degree\n",
+"alfa2=omega_t;//degree\n",
+"disp(alfa1,'Minimum firing angle in degree')\n",
+"disp(alfa2,'Maximum firing angle in degree')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.28: Design_a_UJTcircuit.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_28\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=32;//V\n",
+"Eta=0.63;\n",
+"Ip=10*10^-6;//A\n",
+"Vv=3.5;//V\n",
+"Iv=10*10^-3;//A\n",
+"Vf=0.5;//V\n",
+"f=50;//Hz\n",
+"tau=50*10^-3;//s\n",
+"T=1/f//s\n",
+"Vp=Eta*V+Vf;//V\n",
+"C=0.4*10^-6;//F//assumed\n",
+"disp(C*10^6,'Suitable value of C in micro F ')\n",
+"//V-Ip*R>Vp\n",
+"R_upper=(V-Vp)/Ip;//ohm\n",
+"//V-Iv*R<Vv\n",
+"R_lower=(V-Vv)/Iv;//ohm\n",
+"disp('Value of R should be lie between '+string(R_lower)+' ohm to '+string(R_upper)+' ohm')\n",
+"R=T/C/log(1/(1-Eta));//ohm\n",
+"disp(R,'Suitale value of R in ohm ');\n",
+"R4=tau/C;//ohm\n",
+"disp(R4,'Suitale value of R4 in ohm ');\n",
+"R3=10^4/Eta/V;//ohm\n",
+"disp(R3,'Suitale value of R3 in ohm ');\n",
+"//Answer for R4 is wrong in the book"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.29: Various_component_of_circuit.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_29\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"f=2*1000;//Hz\n",
+"Vdc=10;//V\n",
+"Eta=0.6;\n",
+"Ip=5*10^-3;//A\n",
+"Vf=0.5;//V//assumed\n",
+"Vp=Eta*Vdc+Vf;//V\n",
+"//Vdc-Ip*R>Vp\n",
+"R_upper=(Vdc-Vp)/Ip;//ohm\n",
+"disp('Value of R should be less than '+string(R_upper)+' ohm')\n",
+"C=0.5*10^-6;//F//assumed\n",
+"disp(C*10^6,'Let value of C in micro F ')\n",
+"T=1/f//s\n",
+"R=T/C/log(1/(1-Eta));//ohm\n",
+"disp('For C=0.5 micro F, calculated value of R '+string(R)+' ohm. But it is not suitable');\n",
+"C=1*10^-6;//F//assumed\n",
+"disp(C*10^6,'Let value of C in micro F ')\n",
+"R=T/C/log(1/(1-Eta));//ohm\n",
+"disp('For C=1 micro F, calculated value of R '+string(R)+' ohm. It is suitable');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.2: Equivalent_capacitance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_2\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"dv_dt=190;//V/µs\n",
+"IC=8*10^-3;//A\n",
+"\n",
+"//Solution :\n",
+"C=IC/(dv_dt/10^-6);//F\n",
+"disp(C,'Capacitance of depletion layer in F : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.30: Range_of_firing_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_30\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"R=1000:22000;//ohm\n",
+"Vg=2;//V\n",
+"C=0.47*10^-6;//F\n",
+"f=50;//Hz\n",
+"Xc=1/(2*%pi*f*C);//ohm\n",
+"//When R=1000 ohm\n",
+"theta=atand(min(R)/Xc);//degree\n",
+"Z=min(R)-%i*Xc;//ohm\n",
+"I=Vs/Z;//A\n",
+"Vc=-%i*I*Xc;//V\n",
+"//vc=sqrt(2)*abs(Vc)*sind(omega_t+atand(imag(Vc),real(Vc)))\n",
+"omega_t=asind(Vg/sqrt(2)/abs(Vc))-atand(imag(Vc),real(Vc));//degree\n",
+"alfa1=omega_t;//degree\n",
+"//When R=22000 ohm\n",
+"Z=max(R)-%i*Xc;//ohm\n",
+"I=Vs/Z;//A\n",
+"Vc=-%i*I*Xc;//V\n",
+"//vc=sqrt(2)*abs(Vc)*sind(omega_t+atand(imag(Vc),real(Vc)))\n",
+"omega_t=asind(Vg/sqrt(2)/abs(Vc))-atand(imag(Vc),real(Vc));//degree\n",
+"alfa2=omega_t;//degree\n",
+"disp(alfa1,'Minimum firing angle in degree')\n",
+"disp(alfa2,'Maximum firing angle in degree')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.31: Time_of_conduction.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_31\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=0.8;//ohm\n",
+"L=10*10^-6;//H\n",
+"C=50*10^-6;//F\n",
+"//R<sqrt(4*L/C)\n",
+"Rupper=sqrt(4*L/C);//ohm\n",
+"disp('Maximum value of R should be '+string(Rupper)+' ohm')\n",
+"disp('Given value of R is '+string(R)+' ohm. The circuit is underdamped.')\n",
+"t0=%pi/sqrt(1/L/C-R^2/4/L^2);//s\n",
+"disp(t0,'Time of conduction of thyristor in seconds')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.32: Find_value_of_L_and_C.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_32\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=90;//V\n",
+"Iload=8;//A\n",
+"t_off=40*10^-6;//s\n",
+"//Ipeak=2*Iload;//assumed\n",
+"//V*sqrt(C/L)=2*Iload\n",
+"C_by_L=(2*Iload/V)^2;\n",
+"//t_off=%pi/2*sqrt(L*C)\n",
+"L_into_C=(t_off/%pi*2)^2;\n",
+"C=sqrt(L_into_C*C_by_L);//F\n",
+"L=L_into_C/C;//H\n",
+"disp(L,'Value of L(H)');\n",
+"disp(C,'Value of C(F)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.33: Find_value_of_C.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_33\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"RL=10;//ohm\n",
+"V=100;//V\n",
+"t_off=50*10^-6;//s\n",
+"C=t_off/RL/log(2);//F\n",
+"disp(C,'Value of C(F)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.34: Find_value_of_L_and_C.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_34\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"IL=40;//A\n",
+"VC=100;//V\n",
+"t_off=60*10^-6;//s\n",
+"C=t_off*IL/VC;//F\n",
+"disp(C,'Value of C(F)');\n",
+"//L>VC^2*C/IL\n",
+"L_lower=VC^2*C/IL^2;//H\n",
+"Ip=VC*sqrt(C/L_lower);//A\n",
+"disp('Value of L should be greater than '+string(L_lower)+' H. For this value of L, Peak capacitor current is '+string(Ip)+' A. But it should be less than maximum load current.')\n",
+"//Let Ip=34.6 A\n",
+"Ip=34.6;//A\n",
+"L=C/(Ip/VC)^2;//H\n",
+"disp(L,'Value of L(H)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.35: Current_rating_of_thyristor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_35\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vdc=100;//V\n",
+"L=0.1*10^-3;//H\n",
+"C=10*10^-6;//F\n",
+"Vc=100;//V\n",
+"t_off_thyristor=25*10^-6;//s\n",
+"IL=10;//A\n",
+"t_off=Vc*C/IL;//s\n",
+"disp('T_off is '+string(t_off)+' seconds. It is greater than thristor turn off time, so it is sufficient for communication.')\n",
+"Ip=Vdc*sqrt(C/L);//A\n",
+"disp(Ip,'Current rating(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.36: Find_value_of_R_and_C.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_36\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"dv_by_dt=25/10^-6;//V/s\n",
+"L=0.2*10^-3;//H\n",
+"Vrms=230;//V\n",
+"damping=0.65;//damping factor\n",
+"Vm=sqrt(2)*Vrms;//V\n",
+"C=1/(2*L)*[0.564*Vm/dv_by_dt]^2;//F\n",
+"R=2*damping*sqrt(L/C);//ohm\n",
+"disp(C,'Value of C(F)');\n",
+"disp(R,'Value of R(ohm)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.37: Value_of_R_and_C_Power_loss_and_rating.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_37\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=300;//V\n",
+"RL=10;//ohm\n",
+"L=0;//H\n",
+"Ith=100;//A\n",
+"f=2000;//Hz\n",
+"dv_by_dt=100*10^6;//V/s\n",
+"//dv/dt=(vth(tau)-vth(0))/tau\n",
+"//dv/dt=RL*(1-0.368)*V/(R+RL)/((R+RL)*C)\n",
+"R=V/Ith;//ohm\n",
+"C=RL*(1-0.368)*V/(R+RL)/(R+RL)/dv_by_dt\n",
+"disp(R,'Value of R(ohm)');\n",
+"disp(C,'Value of C(F)');\n",
+"Ploss=1/2*C*V^2*f;//W\n",
+"disp(Ploss,'Power loss in snubber circuit(W)')\n",
+"disp('Power rating of resitance is '+string(Ploss)+' W as all energy will be disspated in the resistance.')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.38: Value_of_dvbydt_and_dibydt.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_38\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=4;//ohm\n",
+"L=6*10^-6;//H\n",
+"C=6*10^-6;//F\n",
+"V=300;//V\n",
+"di_by_dt_max=V/L;//A/s\n",
+"Isc=V/R;//A\n",
+"dvc_by_dt=R*di_by_dt_max+Isc/C;//V/s\n",
+"disp(di_by_dt_max,'Maximum permissible value of di/dt(A/s)');\n",
+"disp(dvc_by_dt,'Maximum permissible value of dv/dt(V/s)');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.39: Design_a_snubber_circuit.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_39\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"RL=8;//ohm\n",
+"V=230;//V\n",
+"Ip=100;//A\n",
+"SF=2;//safety factor\n",
+"di_by_dt_max=40/10^-6/2;//A/s\n",
+"dv_by_dt_max=150/10^-6/2;//V/s\n",
+"\n",
+" L=sqrt(2)*V/di_by_dt_max;//H\n",
+"disp(L,'Value of L(H)');\n",
+"R=L/(sqrt(2)*V)*dv_by_dt_max;//ohm\n",
+"disp(R,'Value of R(ohm)');\n",
+"IL_peak=(sqrt(2)*V)/RL;//A\n",
+"Ic_peak=(sqrt(2)*V)/R;//A\n",
+"Itotal=IL_peak+Ic_peak;//A\n",
+"disp(Itotal,'Total current through capacitor for these values(A)');\n",
+"disp('Itotal>Ip, therefore value of R should be increased.');\n",
+"Ic_max=Ip-IL_peak;//A\n",
+"R=(sqrt(2)*V)/Ic_max;//ohm\n",
+"R=ceil(R);//ohm\n",
+"disp(R,'New Value of R(ohm)');\n",
+"damping=0.65;\n",
+"C=4*damping^2*L/R^2;//F\n",
+"disp(C*10^6,'Value of C(micro F)');\n",
+"disp(L*10^6,'Value of L(micro H)');\n",
+"//Ic_switching=C*dv/dt\n",
+"dv_by_dt=sqrt(2)*V/(R+RL)/C;//V/s\n",
+"disp('Value of dv/dt is '+string(dv_by_dt)+' V/s. It is within the limit for the calculated value of R, L & C. Design is safe.')\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.3: Find_various_voltages.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_3\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"RG=2000;//ohm\n",
+"VCC=20;//V\n",
+"VT=0.75;//V\n",
+"Vthy=0.7;//V(Voltage across thyristor)\n",
+"R=200;//ohm\n",
+"IT=7*10^-3;//A\n",
+"Ih=5*10^-3;//A\n",
+"\n",
+"\n",
+"//Solution :\n",
+"//part (a)\n",
+"Vo=VCC;//V////thyristor not conducting\n",
+"disp(Vo,'(a) When thyristor is in off state, Output voltage in V')\n",
+"//part (b)\n",
+"Vs=VT+IT*RG;//V\n",
+"disp(Vs,'(b) Voltage necessary to turn on the thyristor in V')\n",
+"//part (c)\n",
+"VR1=Ih*R;//V\n",
+"disp('(c) Current through thyristor should be less than holding current. Voltage should be reduced to less than '+string(VR1)+' V')\n",
+"//part (d)\n",
+"VR2=VR1+Vthy;//V\n",
+"disp('(d) VCC should be reduced to less than '+string(VR2)+' V')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.40: Fault_clearing_time.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_40\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=230;//V\n",
+"R1=2;//ohm\n",
+"R2=5;//ohm\n",
+"R3=1;//ohm\n",
+"R4=6;//ohm\n",
+"R5=5;//ohm\n",
+"Isqr_t=30;//A^2-s\n",
+"R=R1+R2*R3/(R2+R3);//ohm(X grounded)\n",
+"Ifault=sqrt(2)*V/R;//A\n",
+"tc=Isqr_t/Ifault^2;//s\n",
+"disp(tc,'Fault clearing time in seconds');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.4: Find_VG_IG_and_RG.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_4\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"IG=poly(0,'IG');//A\n",
+"VG=1+9*IG;//V\n",
+"Vgate=25;//V\n",
+"t=%pi;//radian(duration)\n",
+"Pavg=0.6;//W\n",
+"\n",
+"//Solution :\n",
+"Ploss=Pavg*2*%pi/t;//W\n",
+"//Ploss=VG*IG\n",
+"X=VG*IG-Ploss;\n",
+"IG=roots(X);//A\n",
+"IG=IG(2);//A(taking +ve value only)\n",
+"VG=1+9*IG;//V\n",
+"//Vgate=RG*IG+VG\n",
+"RG=(Vgate-VG)/IG;//ohm\n",
+"disp(VG,'VG in V');\n",
+"disp(IG,'IG in A');\n",
+"disp(RG,'RG in ohm');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.5: Minimum_width_of_gate_pulse.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_5\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"Vdc=100;//V\n",
+"L=10;//H\n",
+"i=80*10^-3;//A\n",
+"\n",
+"//Solution :\n",
+"t=i*L/Vdc;//s\n",
+"disp('Width of pulse should be more than '+string(t*1000)+' milli-seconds.');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.6: Minimum_width_of_gate_pulse.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_6\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"Vdc=100;//V\n",
+"R=10;//ohm\n",
+"L=5;//H\n",
+"i=50*10^-3;//A\n",
+"\n",
+"//Solution :\n",
+"//i=Vdc/R*(1-exp(-R*t/L))\n",
+"t=-log(1-i/Vdc*R)/R*L;//s\n",
+"disp('Minimum width of gate pulse is '+string(t*1000)+' milli-seconds.');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.7: Maximum_value_of_R.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_7\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"i_latch=40*10^-3;//A\n",
+"t=40*10^-6;//s\n",
+"Vdc=90;//V\n",
+"R=25;//ohm\n",
+"L=0.5;//H\n",
+"\n",
+"//Solution :\n",
+"i=Vdc/R*(1-exp(-R*t/L));//A\n",
+"disp('Current in the circuit is '+string(i)+' A, it is less than latchig current, the thyristor will not turn on.');\n",
+"R=Vdc/(i_latch-i);//ohm\n",
+"disp('Maximum value of R is '+string(R)+' ohm.');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.8: Maximum_value_of_R.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_8\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data\n",
+"i_h=50*10^-3;//A\n",
+"t=50*10^-6;//s\n",
+"Vdc=100;//V\n",
+"R=20;//ohm\n",
+"L=0.5;//H\n",
+"\n",
+"//Solution :\n",
+"i=Vdc/R*(1-exp(-R*t/L));//A\n",
+"//i<i_h;;;so thyristor will return to off state\n",
+"iR=i_h-i;//A//current through R\n",
+"R=Vdc/iR;//ohm\n",
+"disp('Maximum value of R is '+string(R)+' ohm.');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.9: Find_Triggering_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 1_9\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=240;//Volt\n",
+"f=50;//Hz\n",
+"R=5;//ohm\n",
+"L=0.05;//H\n",
+"theta=atand(2*%pi*f*L/R);//degree\n",
+"Vm=V*sqrt(2);//Volt\n",
+"//sind(fi-theta)=0;//for no current transient\n",
+"fi=theta+asind(0);//degree\n",
+"disp(fi,'For no current transient, triggering angle in degree');\n",
+"//sind(fi-theta)=1;//for worst current transient\n",
+"fi=theta+asind(1);//degree\n",
+"disp(fi,'For worst current transient, triggering angle in degree');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Introduction_to_Electric_Drives_by_V_Singhal/2-Phase_Controlled_Rectifiers.ipynb b/Introduction_to_Electric_Drives_by_V_Singhal/2-Phase_Controlled_Rectifiers.ipynb
new file mode 100644
index 0000000..5c11f15
--- /dev/null
+++ b/Introduction_to_Electric_Drives_by_V_Singhal/2-Phase_Controlled_Rectifiers.ipynb
@@ -0,0 +1,997 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 2: Phase Controlled Rectifiers"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.10: Average_load_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_10\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"Vdc=100;//V\n",
+"Ip=15;//A\n",
+"alfa=30;//degree\n",
+"\n",
+"//Solution :\n",
+"//Vdc=2*Vm*cosd(alfa)/%pi-2*1.7//(Full converter bridge)\n",
+"Vm=(Vdc+2*1.7)/2/cosd(alfa)*%pi;//V\n",
+"Vrms=Vm/sqrt(2);//V\n",
+"TurnRatio=Vs/Vrms;\n",
+"disp(TurnRatio,'(a) Turn ratio of transformer');\n",
+"Irms=sqrt(Ip^2/2);//A\n",
+"Rating=Vrms*Ip;//VA\n",
+"disp(Rating,'(b) Transformer rating in VA');\n",
+"PIV=Vm;//V\n",
+"disp(PIV,'(c) PIV in V');\n",
+"disp(Irms,'(d) RMS value of thyristor current in A');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.11: Vrms_Vdc_Form_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_11\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"alfa=90;//degree\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=Vm/%pi*(1+cosd(alfa))//V\n",
+"disp(Vdc,'Vdc in V');\n",
+"Vrms=Vm/sqrt(2)*sqrt(1/%pi*[%pi-%pi/2+sin(%pi)/2]);//V\n",
+"disp(Vrms,'Vrms in V');\n",
+"FormFactor=Vrms/Vdc;\n",
+"disp(FormFactor,'Form factor');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.12: Vrms_Vdc_form_factor_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_12\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"alfa=90;//degree\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=Vm/%pi*(1+cosd(alfa))//V\n",
+"disp(Vdc,'Vdc in V');\n",
+"Vrms=Vm/sqrt(2)*sqrt(1/%pi*[%pi-%pi/2+sin(%pi)/2]);//V\n",
+"disp(Vrms,'Vrms in V');\n",
+"Is_by_I=sqrt(1-%pi/2/%pi);\n",
+"Is1_by_I=2*sqrt(2)/%pi*cos(%pi/4);\n",
+"HF=sqrt((Is_by_I/Is1_by_I)^2-1);//unitless\n",
+"disp(HF,'Harmonic factor');\n",
+"theta1=-alfa/2*%pi/180;//radian\n",
+"DF=cos(theta1);//unitless\n",
+"disp(DF,'Displacement factor');\n",
+"PF=(Is1_by_I/Is_by_I)*DF;//lagging\n",
+"disp(PF,'Power factor(lagging)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.13: Vrms_Vdc_form_factor_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_13\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"alfa=%pi/3;//radian\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=2*Vm/%pi*cos(alfa)//V\n",
+"disp(Vdc,'Vdc in V');\n",
+"Vrms=Vs;//V\n",
+"disp(Vrms,'Vrms in V');\n",
+"Is_by_I=sqrt(1-%pi/2/%pi);\n",
+"Is1_by_I=2*sqrt(2)/%pi*cos(%pi/4);\n",
+"HF=sqrt((Is_by_I/Is1_by_I)^2-1);//unitless\n",
+"disp(HF,'Harmonic factor');\n",
+"fi1=-alfa;//radian\n",
+"DF=cos(fi1);//unitless\n",
+"disp(DF,'Displacement factor');\n",
+"PF=(Is1_by_I/Is_by_I)*DF;//lagging\n",
+"disp(PF,'Power factor(lagging)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.14: Find_output_volage_and_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_14\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"alfa=30*%pi/180;//radian\n",
+"I=4;//A\n",
+"\n",
+"//Solution :\n",
+"disp('part (a)');\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=2*Vm/%pi*cos(alfa)//V\n",
+"RL=Vdc/I;//ohm\n",
+"IL=I*2*sqrt(2)/%pi;//A\n",
+"Pin_active=Vs*IL*cos(alfa);//W\n",
+"Pin_reactive=Vs*IL*sin(alfa);//vars\n",
+"Pin_appearent=Vs*IL;//VA\n",
+"disp(Vdc,'dc output voltage(V)');\n",
+"disp(Pin_active,'Active power input(W)');\n",
+"disp(Pin_reactive,'Reactive power input(vars)');\n",
+"disp(Pin_appearent,'Appearent power input(VA)');\n",
+"disp('part (b)');\n",
+"Vdc=Vm/%pi*(1+cos(alfa))//V\n",
+"IL=Vdc/RL;//A\n",
+"I_fund=2*sqrt(2)/%pi*IL*cos(alfa/2);//A\n",
+"Pin_active=Vs*I_fund*cos(alfa/2);//W\n",
+"Pin_reactive=Vs*I_fund*sin(alfa/2);//vars\n",
+"Pin_appearent=Vs*I_fund;//VA\n",
+"disp(Vdc,'dc output voltage(V)');\n",
+"disp(Pin_active,'Active power input(W)');\n",
+"disp(Pin_reactive,'Reactive power input(vars)');\n",
+"disp(Pin_appearent,'Appearent power input(VA)');\n",
+"disp('part (c)');\n",
+"Vdc=Vs/sqrt(2)/%pi*(1+cos(alfa))//V\n",
+"Idc=Vdc/RL;//A\n",
+"disp(Vdc,'dc output voltage(V)');\n",
+"disp(Idc,'dc output current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.15: Voltage_current_and_various_factors.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_15\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"alfa=30;//degree\n",
+"IL=10;//A\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=2*Vm/%pi*cosd(alfa)//V\n",
+"disp(Vdc,'(a) dc output voltage(V)');\n",
+"Irms=IL;//A\n",
+"disp(Irms,'(b) Irms in A');\n",
+"Is1=2*sqrt(2)/%pi*IL;//A\n",
+"disp(Is1,'(c) Fundamental component of input current in A');\n",
+"DF=cosd(-alfa);//unitless\n",
+"disp(DF,'(d) Displacement fator');\n",
+"pf_in=Is1/IL*DF;//lagging\n",
+"disp(pf_in,'(e) Input power fator(lagging)');\n",
+"HF=sqrt((IL/Is1)^2-1);//unitless\n",
+"disp(HF,'(f) Harmonic factor');\n",
+"Vrms=Vs;//V\n",
+"FF=Vrms/Vdc;//form fator\n",
+"RF=sqrt(FF^2-1);//ripple fator\n",
+"disp(RF,'(g) Ripple factor');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.16: Voltage_current_power_factor_and_power_disipated.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_16\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=240;//V\n",
+"f=50;//Hz\n",
+"alfa=60;//degree\n",
+"RL=10;//ohm\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2);//V\n",
+"Vdc=Vm/%pi*(1+cosd(alfa))//V\n",
+"disp(Vdc,'(a) average load voltage(V)');\n",
+"I=Vdc/RL;//A\n",
+"Is=I*sqrt(1-alfa/180);//A\n",
+"Irms=Is;//A\n",
+"disp(Irms,'(b) rms input current(A)');\n",
+"Is1=2*sqrt(2)/%pi*I*cosd(alfa/2);//A\n",
+"fi1=-alfa/2;//degree\n",
+"DF=cosd(fi1);//unitless\n",
+"pf_in=Is1/Is*DF;//lagging\n",
+"disp(pf_in,'(c) Input power fator(lagging)');\n",
+"Pavg=I^2*RL;//W\n",
+"disp(Pavg,'(d) Average power dissipated(W)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.17: Firing_angle_Power_and_variation_in_firing_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_17\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"IL=200;//A\n",
+"VL=400;//V\n",
+"Vdc=360;//V\n",
+"variation=10;//%\n",
+"\n",
+"//Solution :\n",
+"Vm=VL*sqrt(2)/sqrt(3);//V\n",
+"//Vdc=3*sqrt(3)/%pi*Vm*cosd(alfa)//V\n",
+"alfa=acosd(Vdc/(3*sqrt(3)/%pi*Vm))//degree\n",
+"disp(alfa,'Firing angle in degree');\n",
+"S=sqrt(3)*VL*IL;//VA\n",
+"disp(S,'Apparent power(VA)');\n",
+"P=S*cosd(alfa);//W\n",
+"disp(P,'Active power(W)');\n",
+"Q=sqrt(S^2-P^2);//vars\n",
+"disp(Q,'Rective power(vars)');\n",
+"Vac1=(1+variation/100)*VL;//V\n",
+"alfa1=acosd(Vdc/(3*Vac1*sqrt(2)/%pi));//degree\n",
+"Vac2=(1-variation/100)*VL;//V\n",
+"alfa2=acosd(Vdc/(3*Vac2*sqrt(2)/%pi));//degree\n",
+"disp(alfa1,'When variation is +10%, firing angle(degree)');\n",
+"disp(alfa2,'When variation is -10%, firing angle(degree)');\n",
+"//Answer in the book is wrong for some part."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.18: Pdc_Current_and_PIV.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_18\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=400;//V\n",
+"f=50;//Hz\n",
+"Idc=150;//A\n",
+"alfa=60;//degree\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2)/sqrt(3);//V\n",
+"Vdc=3*sqrt(3)/%pi*Vm*cosd(alfa)//V\n",
+"Pdc=Vdc*Idc;//W\n",
+"disp(Pdc,'Output power, Pdc(W)');\n",
+"Iavg=Idc/3;//A\n",
+"disp(Iavg,'Average thyristor current(A)');\n",
+"Irms=Idc/sqrt(3);//A\n",
+"disp(Irms,'RMS value of thyristor current(A)');\n",
+"Ipeak=Idc;//A\n",
+"disp(Ipeak,'Peak current through thyristor(A)');\n",
+"PIV=sqrt(2)*Vs;//V\n",
+"disp(PIV,'Peak inverse voltage(V)');\n",
+"//Answer of first part in the book is wrong."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.19: Firing_angle_Power_and_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_19\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=415;//V\n",
+"Vdc=460;//V\n",
+"I=200;//A\n",
+"f=50;//Hz\n",
+"\n",
+"//Solution :\n",
+"Vm=V*sqrt(2)/sqrt(3);//V\n",
+"alfa=acosd(Vdc/(3*sqrt(3)/%pi*Vm));//degree\n",
+"disp(alfa,'Converter firing angle(degree)');\n",
+"Pdc=Vdc*I;//W\n",
+"disp(Pdc/1000,'dc power(kW)');\n",
+"IL=I*sqrt(120/180);//A\n",
+"disp(IL,'AC line current(A)');\n",
+"Ipeak=I;//A\n",
+"Irms=Ipeak*sqrt(120/360);//A\n",
+"disp(Irms,'RMS value of thyristor current(A)');\n",
+"Iavg=Ipeak/3;//A\n",
+"disp(Iavg,'Average thyristor current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.1: Average_Load_and_rms_load_voltage_and_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_1\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vin=400;//V\n",
+"alfa=30;//degree\n",
+"R=50;//ohm\n",
+"\n",
+"//Solution :\n",
+"Vdc=Vin/%pi/2*(1+cosd(alfa));//V\n",
+"disp(Vdc,'Average load voltage(V) : ');\n",
+"I=Vdc/R;//A\n",
+"disp(I,'Average load current(A) : ');\n",
+"Vrms=Vin*sqrt((180-alfa)/4/180+sind(2*alfa)/8/%pi);//V\n",
+"disp(Vrms,'rms load voltage(V) : ');\n",
+"Irms=Vrms/R;//A\n",
+"disp(Irms,'rms load current(A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.20: Firing_angle_and_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_20\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"emf=200;//V\n",
+"Rint=0.5;//ohm\n",
+"I=20;//A\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2)/sqrt(3);//V\n",
+"Vdc=emf+Rint*I;//V\n",
+"alfa=acosd(Vdc/(3*sqrt(3)/%pi*Vm));//degree\n",
+"disp(alfa,'Firing angle(degree)');\n",
+"Pout=emf*I+I^2*Rint;//W\n",
+"Is=sqrt(I^2*120/180);//A\n",
+"cos_theta=Pout/(sqrt(3)*Vs*Is);//power factor\n",
+"disp(cos_theta,'Input power factor(lagging)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.21: Firing_angle_current_and_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_21\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=400;//V\n",
+"R=10;//ohm\n",
+"f=50;//Hz\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2)/sqrt(3);//V\n",
+"Vdc_max=3*sqrt(3)*Vm/2/%pi*(1+cosd(0));//V\n",
+"//Vdc should be Vdc_max/2\n",
+"Vdc=Vdc_max*50/100;//V\n",
+"alfa=acosd(1-Vdc/(3*sqrt(3)*Vm/2/%pi));//degree\n",
+"disp(alfa,'Firing angle(degree)');\n",
+"Idc=Vdc/R;//A\n",
+"disp(Idc,'Average output current(A)');\n",
+"Vrms=sqrt(3)*Vm*sqrt(3/4/%pi*(%pi-%pi/2+sin(%pi)/2));//V\n",
+"Irms=Vrms/R;//A\n",
+"disp(Vrms,'RMS output voltage(V)');\n",
+"disp(Irms,'RMS output current(A)');\n",
+"Iavg_thy=Idc/3;//A\n",
+"disp(Iavg_thy,'Average thyristor current(A)');\n",
+"Irms_thy=Irms/sqrt(3);//A\n",
+"disp(Irms_thy,'RMS thyristor current(A)');\n",
+"Eff=Vdc*Idc/(Vrms*Irms)*100;//%\n",
+"disp(Eff,'Rectification Efficiency(%)');\n",
+"Iline_rms=Irms*sqrt(120/180);//A\n",
+"VA_in=3*Vs*Iline_rms/sqrt(3);//VA\n",
+"TUF=Vdc*Idc/VA_in;\n",
+"disp(TUF,'Transformer utilisation factor');\n",
+"Pin_active=Irms^2*R;//W\n",
+"pf_in=Pin_active/VA_in;//lagging\n",
+"disp(pf_in,'Input power factor(lagging)');\n",
+"//Answer in the book is wrong for some part."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.22: Firing_angle_current_and_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_22\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=400;//V\n",
+"R=10;//ohm\n",
+"f=50;//Hz\n",
+"\n",
+"//Solution :\n",
+"Vm=Vs*sqrt(2)/sqrt(3);//V\n",
+"alfa=60;//degree(For 50% output voltage)\n",
+"Vdc=3*sqrt(3)*Vm/%pi*cosd(alfa);//V\n",
+"alfa=acosd(Vdc/3/sqrt(3)/Vm*%pi);//V\n",
+"disp(alfa,'Firing angle in degree');\n",
+"Idc=Vdc/R;//A\n",
+"disp(Idc,'Average output current(A)');\n",
+"Vrms=sqrt(3)*Vm*sqrt(0.5+3*sqrt(3)/4/%pi*cosd(2*alfa));//V\n",
+"Irms=Vrms/R;//A\n",
+"disp(Vrms,'RMS output voltage(V)');\n",
+"disp(Irms,'RMS output current(A)');\n",
+"Iavg_thy=Idc/3;//A\n",
+"disp(Iavg_thy,'Average thyristor current(A)');\n",
+"Irms_thy=Irms/sqrt(3);//A\n",
+"disp(Irms_thy,'RMS thyristor current(A)');\n",
+"Eff=Vdc*Idc/(Vrms*Irms)*100;//%\n",
+"disp(Eff,'Rectification Efficiency(%)');\n",
+"Iline_rms=Irms*sqrt(120/180);//A\n",
+"VA_in=3*Vs*Iline_rms/sqrt(3);//VA\n",
+"TUF=Vdc*Idc/VA_in;\n",
+"disp(TUF,'Transformer utilisation factor');\n",
+"Pin_active=Irms^2*R;//W\n",
+"pf_in=Pin_active/VA_in;//lagging\n",
+"disp(pf_in,'Input power factor(lagging)');\n",
+"//Answer in the book is wrong for some part."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.25: Firing_angle_of_converter.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_25\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=400;//V\n",
+"f=50;//Hz\n",
+"Eb=300;//V\n",
+"\n",
+"//Solution :\n",
+"Vdc=Eb;//V\n",
+"Vm=Vs*sqrt(2);//V\n",
+"//Vdc=3*sqrt(3)/2/%pi*Vm*cosd(alfa);//V\n",
+"alfa=acosd(Vdc/(3*sqrt(3)/2/%pi*Vm));//degree\n",
+"disp(alfa,'Firing angle(degree)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.2: Find_average_curren.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_2\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vo=50;//V\n",
+"R=10;//ohm\n",
+"//Vin=100*sin(omega*t);//V\n",
+"Vm=100;//V\n",
+"\n",
+"//Solution :\n",
+"omega_t=asin(Vo/Vm);//radian\n",
+"Iavg=1/2/%pi*integrate('(Vm*sin(omega_t)-Vo)/R','omega_t',omega_t,omega_t+2*%pi/3);//A\n",
+"disp(Iavg,'Average current in the circuit(A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.3: Find_average_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_3\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Eb=55.5;//V\n",
+"R=10;//ohm\n",
+"//Vin=110*sin(omega*t);//V\n",
+"Vm=110*sqrt(2);//V\n",
+"\n",
+"//Solution :\n",
+"omega_t=asind(Eb/Vm);//degree\n",
+"Iavg=1/2/180*integrate('(Vm*sind(omega_t)-Eb)/R','omega_t',omega_t,180-omega_t);//A\n",
+"disp(Iavg,'Average current in the circuit(A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4: Vdc_Idc_Vrms_Irms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_4\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"R=15;//ohm\n",
+"alfa=%pi/2;//radian\n",
+"\n",
+"//Solution :\n",
+"Vm=sqrt(2)*Vs;//V\n",
+"Vdc=Vm/2/%pi*(1+cos(alfa));//V\n",
+"disp(Vdc,'Vdc(V) : ');\n",
+"Idc=Vdc/R;//A\n",
+"disp(Idc,'Idc(A) : ');\n",
+"Vrms=Vm*sqrt((%pi-alfa)/4/%pi+sin(%pi)/8/%pi);//V\n",
+"disp(Vrms,'Vrms(V) : ');\n",
+"Irms=Vrms/R;//A\n",
+"disp(Irms,'Irms(A) : ');\n",
+"Pdc=Vdc*Idc;//W\n",
+"disp(Pdc,'Pdc(W) : ');\n",
+"Pac=Vrms*Irms;//W\n",
+"disp(Pac,'Pac(W) : ');\n",
+"R_eff=Pdc/Pac;//rectification efficiency\n",
+"disp(R_eff,'Rectification efficiency(unitless) : ');\n",
+"Kf=Vrms/Vdc;//Form factor\n",
+"disp(Kf,'Form factor(unitless) : ');\n",
+"Kr=sqrt(Kf^2-1);//Ripple factor\n",
+"disp(Kr,'Ripple factor(unitless) : ');\n",
+"VA_rating=Vs*Irms;//VA\n",
+"disp(VA_rating,'VoltAmpere rating(VA) : ');\n",
+"TUF=Pdc/VA_rating;//Transformer utilization factor\n",
+"disp(TUF,'Transformer utilization factor(unitless) : ');\n",
+"PIV=Vm;//V\n",
+"disp(PIV,'Peak Inverse Voltage across thyristor(V) : ');\n",
+"//Ans in the book is wrong for some part."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.5: Vdc_Vrms_Irms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_5\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vo=150;//V\n",
+"R=30;//ohm\n",
+"alfa=45;//degree\n",
+"\n",
+"//Solution :\n",
+"Vdc=sqrt(2)*Vo/%pi*(1+cosd(alfa));//V\n",
+"disp(Vdc,'Average dc Voltage(V) : ');\n",
+"Iavg=Vdc/R;//A\n",
+"disp(Iavg,'Average load current(A) : ');\n",
+"Vrms=sqrt(2)*Vo*sqrt((180-alfa)/2/180+sind(90)/4/%pi   );//V\n",
+"disp(Vrms,'rms load Voltage(V) : ');\n",
+"Irms=Vrms/R;//A\n",
+"disp(Irms,'rms load current(A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.6: Turn_ratio_VA_rating_PIV.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_6\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"Vdc=100;//V\n",
+"Ip=15;//A\n",
+"alfa=30;//degree\n",
+"\n",
+"//Solution :\n",
+"Vm=Vdc*%pi/(2*cosd(alfa))+1.7;//V\n",
+"Vrms_2nd=Vm/sqrt(2);//V\n",
+"TurnRatio=Vs/Vrms_2nd;\n",
+"disp(TurnRatio,'(a) Turn ratio of transformer');\n",
+"Irms_2nd=sqrt(Ip^2/2);//A\n",
+"Rating=2*Vrms_2nd*Irms_2nd;//VA\n",
+"disp(Rating,'(b) Transformer rating in VA');\n",
+"PIV=2*Vm;//V\n",
+"disp(PIV,'(c) PIV in V');\n",
+"disp(Irms_2nd,'(d) RMS value of thyristor current in A');\n",
+"///Answer in the book is wrong for some part."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.7: Rated_voltage_of_thyristor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_7\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"P=10;//kW\n",
+"Idc=50;//A\n",
+"SF=2;//safety factor\n",
+"\n",
+"//Solution :\n",
+"Vdc=P*1000/Idc;//V\n",
+"alfa=0;//degree\n",
+"Vm=Vdc*%pi/(2*cosd(alfa))+1.7;//V\n",
+"PIV=2*Vm;//V\n",
+"Vthy=SF*PIV;//V\n",
+"disp(Vthy,'(a) Voltage rating of thristor in V');\n",
+"PIV=Vm;//V//for bridge rectifier\n",
+"Vthy=SF*PIV;//V\n",
+"disp(Vthy,'(b) Voltage rating of thristor in V');\n",
+"///Answer in the book is wrong."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.8: Firing_angle_and_power_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_8\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Vs=230;//V\n",
+"f=50;//Hz\n",
+"Io=15;//A\n",
+"R=0.5;//ohm\n",
+"L=0.3;//H\n",
+"E1=100;//V\n",
+"E2=-100;//V\n",
+"\n",
+"//Solution :\n",
+"///part (a)\n",
+"Vm=sqrt(2)*Vs;//V\n",
+"//2*Vm/%pi*cosd(alfa)=E1+Io*R\n",
+"alfa1=acosd((E1+Io*R)/(2*Vm/%pi));//degree\n",
+"disp(alfa1,'(a) Firing angle in degree');\n",
+"///part (b)\n",
+"alfa2=acosd((E2+Io*R)/(2*Vm/%pi));//degree\n",
+"disp(alfa2,'(b) Firing angle in degree');\n",
+"disp('Part(c)');\n",
+"//Pin=Vs*Io*cosd(theta)\n",
+"Pout=E1*Io+Io^2*R;//W\n",
+"//Pin=Pout\n",
+"cos_theta=(Pout/Vs/Io);//laging\n",
+"disp(cos_theta,'When E=100, input power factor(lagging)');\n",
+"Pout=-E2*Io-Io^2*R;//W\n",
+"//Pin=Pout\n",
+"cos_theta=(Pout/Vs/Io);//laging\n",
+"disp(cos_theta,'When E=-100, input power factor(lagging)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.9: Average_load_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 2_9\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=230;//V\n",
+"f=50;//Hz\n",
+"R=5;//ohm\n",
+"L=8*10^-3;//H\n",
+"E=50;//V\n",
+"alfa=40;//degree\n",
+"\n",
+"//Solution :\n",
+"//Vdc=2*sqrt(2)*V*cosd(alfa)/%pi=E+Io*R\n",
+"Io=(2*sqrt(2)*V*cosd(alfa)/%pi-E)/R;//A\n",
+"disp(Io,'Average value of load current in A');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Introduction_to_Electric_Drives_by_V_Singhal/3-Inverters.ipynb b/Introduction_to_Electric_Drives_by_V_Singhal/3-Inverters.ipynb
new file mode 100644
index 0000000..f2600f7
--- /dev/null
+++ b/Introduction_to_Electric_Drives_by_V_Singhal/3-Inverters.ipynb
@@ -0,0 +1,344 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 3: Inverters"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.1: Maximum_output_frequency.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_1\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=80;//ohm\n",
+"L=8;///mH\n",
+"C=1.2;// micro F\n",
+"\n",
+"//Solution :\n",
+"if R^2<4*(L*10^-3)/(C*10^-6) then\n",
+"    disp('As R^2<4*L/C, Circuit will work as a series inverter.');\n",
+"else\n",
+"    disp('As R^2>4*L/C, Circuit will not work as a series inverter.');\n",
+"end\n",
+"omega_m=sqrt(1/(L*10^-3*C*10^-6)-R^2/4/(L*10^-3)^2);//rad/s\n",
+"fm=omega_m/2/%pi;//Hz\n",
+"disp(fm,'Maximum frequency in Hz : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.2: Frequency_of_output.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_2\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=80;//ohm\n",
+"L=8;///mH\n",
+"C=1.2;// micro F\n",
+"Toff=14;//micro sec\n",
+"\n",
+"//Solution :\n",
+"omega_m=sqrt(1/(L*10^-3*C*10^-6)-R^2/4/(L*10^-3)^2);//rad/s\n",
+"fm=omega_m/2/%pi;//Hz\n",
+"T=1/fm;//sec\n",
+"f=1/(T+2*Toff*10^-6);//Hz\n",
+"disp(f,'Frequency of output in Hz : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.3: Voltage_power_and_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_3\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"RL=3;//in ohm\n",
+"V=30;//in V\n",
+"\n",
+"//Solution :\n",
+"Vpeak=2*V/%pi;//V\n",
+"Vrms=Vpeak/sqrt(2);//V\n",
+"disp(Vrms,'(a) RMS value of output voltage(V) : ');\n",
+"//VL=sqrt(2/T*integrate('(V/2)^2','t',0,T/2));//V\n",
+"VL=V/2;//V\n",
+"Pout=VL^2/RL;//W\n",
+"disp(Pout,'(b) Output power(W) : ');\n",
+"Ipeak=VL/RL;//A\n",
+"disp(Ipeak,'(c) Peak current in thyristor(A) : ');\n",
+"Iavg=Ipeak*50/100;//A\n",
+"disp(Iavg,'(d) Average current of each thyristor(A) : ');\n",
+"Vprb=2*VL;//V\n",
+"disp(Vprb,'(e) Peak reverse braking voltage(V) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.4: Voltage_power_and_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_4\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"RL=3;//in ohm\n",
+"V=30;//in V\n",
+"\n",
+"//Solution :\n",
+"Vpeak=4*V/%pi;//V\n",
+"Vrms=Vpeak/sqrt(2);//V\n",
+"disp(Vrms,'(a) RMS value of output voltage in volt : ');\n",
+"//VL=sqrt(2/T*integrate('V^2','t',0,T/2));//V\n",
+"VL=V;//V\n",
+"Pout=VL^2/RL;//W\n",
+"disp(Pout,'(b) Output power(W) : ');\n",
+"Ipeak=VL/RL;//A\n",
+"disp(Ipeak,'(c) Peak current in thyristor(A) : ');\n",
+"Iavg=Ipeak*50/100;//A\n",
+"disp(Iavg,'(d) Average current of each thyristor(A) : ');\n",
+"Vprb=VL;//V\n",
+"disp(Vprb,'(e) Peak reverse braking voltage(V) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.5: Current_Distortion_and_power.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_5\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=200;//V\n",
+"R=10;//in ohm\n",
+"L=20;//mH\n",
+"C=100;//pF\n",
+"f=50;//Hz\n",
+"\n",
+"//Solution :\n",
+"Z1=R+%i*(2*%pi*f*L*10^-3-1/(2*%pi*f*C*10^-6));//ohm\n",
+"Z3=R+%i*(3*2*%pi*f*L*10^-3-1/(3*2*%pi*f*C*10^-6));//ohm\n",
+"Z5=R+%i*(5*2*%pi*f*L*10^-3-1/(5*2*%pi*f*C*10^-6));//ohm\n",
+"Z7=R+%i*(7*2*%pi*f*L*10^-3-1/(7*2*%pi*f*C*10^-6));//ohm\n",
+"Z9=R+%i*(9*2*%pi*f*L*10^-3-1/(9*2*%pi*f*C*10^-6));//ohm\n",
+"I=4*V/%pi/abs(Z1);//A\n",
+"Irms=I/sqrt(2);//A\n",
+"disp(Irms,'RMS load current(A)');\n",
+"Ip=sqrt((4*V/%pi/abs(Z1))^2+(4*V/3/%pi/abs(Z3))^2+(4*V/5/%pi/abs(Z5))^2+(4*V/7/%pi/abs(Z7))^2+(4*V/9/%pi/abs(Z9))^2);//A\n",
+"disp(Ip,'Peak value of load current(A)');\n",
+"Ih=sqrt(Ip^2-I^2)/sqrt(2);//A\n",
+"disp(Ih,'RMS harmonic current(A)');\n",
+"hd=sqrt(Ip^2-I^2)/I;//harmonic distortion\n",
+"disp(hd*100,'Harmonic distortion(%)');\n",
+"Irms_load=Ip/sqrt(2);//A\n",
+"Pout=Irms_load^2*R;//W\n",
+"disp(Pout,'Total output power(W)');\n",
+"Pout_com=Irms^2*R;//W(fundamental component)\n",
+"disp(Pout_com,'Fundamental component of power(W)');\n",
+"Iavg_in=Pout/V;//A\n",
+"disp(Iavg_in,'Average input current(A)');\n",
+"Ip_thy=Ip;//A\n",
+"disp(Ip_thy,'Peak thyristor current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.6: Find_value_of_C.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_6\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=2;//in ohm\n",
+"XL=10;//ohm\n",
+"f=4;//kHz\n",
+"Toff=12;//micro sec\n",
+"\n",
+"//Solution :\n",
+"Toff_time=Toff*1.5;//micro sec\n",
+"theta=2*%pi*f*10^3*Toff_time*10^-6;//radians\n",
+"Xc=tan(theta)*R+XL;//ohm\n",
+"C=1/(2*%pi*f*1000*Xc);//F\n",
+"disp(C,'Value of Capacitance in F : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.7: Current_and_power.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_7\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=400;//V\n",
+"R=10;//in ohm/phase\n",
+"\n",
+"//Solution :\n",
+"Ipeak=V/2/R;//A\n",
+"Irms=sqrt(Ipeak^2*2/3);//A\n",
+"disp(Irms,'RMS load current in A : ');\n",
+"Pout=Irms^2*R*3;//W\n",
+"disp(Pout,'Power output(W) : ');\n",
+"Iavg=Ipeak/3;//A\n",
+"disp(Iavg,'Average thyristor current(A) : ');\n",
+"Irms_thyristor=sqrt(Ipeak^2/3);//A\n",
+"disp(Irms_thyristor,'RMS value of thyristor current(A) : ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.8: Current_and_power.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 3_8\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=400;//V\n",
+"R=10;//in ohm/phase\n",
+"\n",
+"//Solution :\n",
+"RL=R+R/2;//ohm\n",
+"i1=V/RL;//A\n",
+"i2=V/RL;//A\n",
+"i3=V/RL;//A\n",
+"Irms_load=sqrt(1/2/%pi*(integrate('i1^2','theta',0,2*%pi/3)+integrate('(i1/2)^2','theta',2*%pi/3,2*%pi)));//A\n",
+"disp(Irms_load,'RMS load current in A : ');\n",
+"Pout=Irms_load^2*R*3;//W\n",
+"disp(Pout,'Power output(W): ');\n",
+"Ipeak=i1;//A\n",
+"Iavg=1/2/%pi*[Ipeak*%pi/3+Ipeak/2*2*%pi/3];//A\n",
+"disp(Iavg,'Average thyristor current(A) : ');\n",
+"Irms_thyristor=sqrt(1/2/%pi*[Ipeak^2*%pi/3+(Ipeak/2)^2*2*%pi/3]);//A\n",
+"disp(Irms_thyristor,'RMS value of thyristor current(A) : ');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Introduction_to_Electric_Drives_by_V_Singhal/4-Choppers.ipynb b/Introduction_to_Electric_Drives_by_V_Singhal/4-Choppers.ipynb
new file mode 100644
index 0000000..78937f5
--- /dev/null
+++ b/Introduction_to_Electric_Drives_by_V_Singhal/4-Choppers.ipynb
@@ -0,0 +1,705 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 4: Choppers"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.10: Average_load_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_10\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=230;//V\n",
+"Ton=25/1000;//s\n",
+"Toff=10/1000;//s\n",
+"\n",
+"//Solution :\n",
+"Vavg=V*Ton/(Ton+Toff);//V\n",
+"disp(Vavg,'Average load voltage(V)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.11: Find_curent_and_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_11\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=100;//V\n",
+"R=0.5;//ohm\n",
+"L=1/1000;//H\n",
+"Ton=1/1000;//s\n",
+"T=3/1000;//s\n",
+"\n",
+"//Solution :\n",
+"Toff=T-Ton;//s\n",
+"alfa=Ton/T;//duty cycle\n",
+"E=0;//V\n",
+"Imax=V/R*[(1-exp(-alfa*T*R/L))/(1-exp(-T*R/L))]-E/R;//A\n",
+"Imin=V/R*[(exp(alfa*T*R/L)-1)/(exp(T*R/L)-1)]-E/R;//A\n",
+"disp(Imax,'Maximum current(A)');\n",
+"disp(Imin,'Minimum current(A)');\n",
+"Iavg=(Imax+Imin)/2;//A\n",
+"disp(Iavg,'Average load current(A)');\n",
+"Vavg=alfa*V;//V\n",
+"disp(Vavg,'Average load voltage(V)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.12: Output_current_and_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_12\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=100;//V\n",
+"E=12;//V\n",
+"L=0.8/1000;//H\n",
+"R=0.2;//ohm\n",
+"T=2.4/1000;//s\n",
+"Ton=1/1000;//s\n",
+"\n",
+"//Solution :\n",
+"alfa=Ton/T;//duty cycle\n",
+"Imax=V/R*[(1-exp(-alfa*T*R/L))/(1-exp(-T*R/L))];//A\n",
+"Imin=V/R*[(exp(alfa*T*R/L)-1)/(exp(T*R/L)-1)];//A\n",
+"disp(Imax,'Maximum current(A)');\n",
+"disp(Imin,'Minimum current(A)');\n",
+"Vavg=alfa*V;//V\n",
+"disp(Vavg,'Average load voltage(V)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.13: Find_series_inductance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_13\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=500;//V\n",
+"I=10;//A\n",
+"f=400;//Hz\n",
+"\n",
+"//Solution :\n",
+"alfa=0.5;//for maximum swing\n",
+"//I=V/(4*f*L);//A\n",
+"L=V/(4*f*I);//H\n",
+"disp(L,'Series inductance(H)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.14: Motor_speed_and_current_swing.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"////Example 4_14\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=800;//V\n",
+"P=300;//HP\n",
+"Eff=0.9;//Efficiency\n",
+"R=0.1;//ohm\n",
+"L=100/1000;//H\n",
+"alfa=0.2;//duty cycle\n",
+"N=900;//rpm\n",
+"f=400;//Hz\n",
+"\n",
+"//Solution :\n",
+"Pout=P*735.5/1000;//kW\n",
+"Pin=Pout/Eff;//kW\n",
+"I=Pin*1000/V;//A\n",
+"E=V-I*R;//V(at rated voltage)\n",
+"Edash=V*alfa-I*R;//V(at 0.2 duty cycle)\n",
+"Ndash=N*Edash/E;//rpm\n",
+"disp(Ndash,'Motor speed(rpm)');\n",
+"T=1/f;//s\n",
+"d_ia=(V-alfa*V)/L*alfa*T;//A\n",
+"disp(d_ia,'Current swing(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.17: Find_the_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"////Example 4_17\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=200;//V\n",
+"R=2;//ohm\n",
+"L=10/1000;//H\n",
+"E=20;//V\n",
+"T=1000/10^6;//s\n",
+"Ton=300/10^6;//s\n",
+"\n",
+"//Solution :\n",
+"f=1/T;//Hz\n",
+"alfa_min=1/(R*T/L)*log(1+E/V*(exp(R*T/L)-1));//duty cycle\n",
+"alfa=Ton/T;//duty cycle\n",
+"disp(alfa_min,'Minimum value required of alfa');\n",
+"disp(alfa,'Actual value of alfa');\n",
+"disp('Load current is continuous as alfa_actual>alfa_min')\n",
+"Imax=V/R*[(1-exp(-alfa*T*R/L))/(1-exp(-T*R/L))]-E/R;//A\n",
+"Imin=V/R*[(exp(alfa*T*R/L)-1)/(exp(T*R/L)-1)]-E/R;//A\n",
+"disp(Imax,'Maximum current(A)');\n",
+"disp(Imin,'Minimum current(A)');\n",
+"Iavg=(alfa*V-E)/R;//A\n",
+"disp(Iavg,'Average load current(A)');\n",
+"Iavg_in=alfa*(V-E)/R-L/R/T*(Imax-Imin);//A\n",
+"disp(Iavg_in,'Average input current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.18: RMS_value_of_load_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"////Example 4_18\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=200;//V\n",
+"T=1000/10^6;//s\n",
+"Ton=300/10^6;//s\n",
+"R=4;//ohm\n",
+"L=10/1000;//H\n",
+"\n",
+"//Solution :\n",
+"f=1/T;//Hz\n",
+"Vrms1=sqrt((200/%pi*sin(2*%pi*0.3))^2+(200/%pi*((1-cos(2*%pi*0.3))))^2)/sqrt(2);//V\n",
+"Vrms2=sqrt((200/2/%pi*sin(2*%pi*2*0.3))^2+(200/2/%pi*((1-cos(2*%pi*2*0.3))))^2)/sqrt(2);//V\n",
+"Vrms3=sqrt((200/3/%pi*sin(2*%pi*3*0.3))^2+(200/3/%pi*((1-cos(2*%pi*3*0.3))))^2)/sqrt(2);//V\n",
+"Z1=R+%i*(2*%pi*f*L);//ohm\n",
+"I1=Vrms1/abs(Z1);//A\n",
+"disp(I1,'RMS value of 1st harmonic of load current(A)');\n",
+"Z2=R+%i*(2*2*%pi*f*L);//ohm\n",
+"I2=Vrms2/abs(Z2);//A\n",
+"disp(I2,'RMS value of 2nd harmonic of load current(A)');\n",
+"Z3=R+%i*(3*2*%pi*f*L);//ohm\n",
+"I3=Vrms3/abs(Z3);//A\n",
+"disp(I3,'RMS value of 3rd harmonic of load current(A)');\n",
+"Iavg=V/R*Ton/T;//A\n",
+"Irms=sqrt(Iavg^2+I1^2+I2^2+I3^2);//A\n",
+"disp(Irms,'RMS value of load current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.19: Period_of_conduction.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_19\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=200;//V\n",
+"Vav=250;//V\n",
+"Toff=0.6*10^-3;//s\n",
+"\n",
+"//Solution :\n",
+"T=Vav/V*Toff;//s\n",
+"Ton=T-Toff;//s\n",
+"disp(Ton,'Period of conduction(seconds)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.1: Period_of_conduction_and_blocking.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_1\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=230;//V\n",
+"Vav=150;//V\n",
+"f=1*1000;//Hz\n",
+"\n",
+"//Solution :\n",
+"T=1/f;//s\n",
+"Ton=Vav*T/V;//s\n",
+"Toff=T-Ton;//s\n",
+"disp(Toff,Ton,'Periods of conduction & blocking(seconds)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.20: Period_of_conduction.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_20\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=150;//V\n",
+"Vav=250;//V\n",
+"Toff=1*10^-3;//s\n",
+"\n",
+"//Solution :\n",
+"T=Vav/V*Toff;//s\n",
+"Ton=T-Toff;//s\n",
+"disp(Ton,'Period of conduction(seconds)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.2: Periods_of_conduction_and_blocking.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_2\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Ra=0.06;//ohm\n",
+"Rf=0.03;//ohm\n",
+"Iav=15;//A\n",
+"f=500;//Hz\n",
+"Eb=100;//V\n",
+"V=200;//V\n",
+"\n",
+"//Solution :\n",
+"Vav=Iav*(Ra+Rf)+Eb;//V\n",
+"T=1/f;//s\n",
+"Ton=Vav*T/V;//s\n",
+"Toff=T-Ton;//s\n",
+"disp(Toff,Ton,'Periods of conduction & blocking(seconds)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.3: Find_duty_cycle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_3\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"N=800;//rpm\n",
+"I=20;//A\n",
+"Ra=0.5;//ohm\n",
+"Vs=240;//V\n",
+"Ndash=600;//rpm\n",
+"\n",
+"//Solution :\n",
+"Eb_800=Vs-I*Ra;//V\n",
+"Eb_600=Eb_800*Ndash/N;//V\n",
+"Vav=I*Ra+Eb_600;//V\n",
+"alfa=Vav/Vs;//duty cycle\n",
+"disp(alfa,'(a) Duty cycle');\n",
+"//Torque reduced to half will reduce I to half\n",
+"I=I/2;//A\n",
+"Vav=I*Ra+Eb_600;//V\n",
+"alfa=Vav/Vs;//duty cycle\n",
+"disp(alfa,'(b) Duty cycle');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.4: Voltage_Efficiency_and_resistance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_4\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=200;//V\n",
+"RL=8;//ohm\n",
+"Vthy=2;//V\n",
+"f=800;//Hz\n",
+"alfa=0.4;//duty cycle\n",
+"\n",
+"//Solution :\n",
+"Vav=alfa*(V-Vthy);//V\n",
+"disp(Vav,'(a) Average output voltage(V)');\n",
+"VL=sqrt(alfa)*(V-Vthy);//V\n",
+"disp(VL,'(b) RMS output voltage(V)');\n",
+"Pout=VL^2/RL;//W\n",
+"Pin=alfa*V*(V-Vthy)/RL;//W\n",
+"Eff=Pout/Pin*100;//%\n",
+"disp(Eff,'(c) Chopper efficiency(%)');\n",
+"Rin=RL/alfa;//ohm\n",
+"disp(Rin,'(d) Input resistance(ohm)');\n",
+"V1=(V-Vthy)*sqrt(2)/%pi;//V\n",
+"disp(V1,'(e) RMS value of fundamental component(V)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.5: Chopping_frequency.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_5\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=400;//V\n",
+"R=0;//ohm\n",
+"L=0.05;//H\n",
+"alfa=0.25;//duty cycle\n",
+"delta_i=10;//A\n",
+"\n",
+"//Solution :\n",
+"Vav=alfa*V;//V\n",
+"delta_T=L*delta_i/(V-Vav);//s\n",
+"Ton=delta_T;///s\n",
+"T=Ton/alfa;//s\n",
+"f=1/T;//pulses/s\n",
+"disp(f,'Chopping frequency(pulses/s)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.6: Find_the_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_6\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"R=4;//ohm\n",
+"L=6/1000;//H\n",
+"V=200;//V\n",
+"alfa=0.5;//duty cycle\n",
+"f=1000;//Hz\n",
+"\n",
+"//Solution :\n",
+"T=1/f;//s\n",
+"E=0;//V\n",
+"Imax=V/R*[(1-exp(-alfa*T*R/L))/(1-exp(-T*R/L))]-E/R;//A\n",
+"Imin=V/R*[(exp(alfa*T*R/L)-1)/(exp(T*R/L)-1)]-E/R;//A\n",
+"disp(Imax,'Maximum current(A)');\n",
+"disp(Imin,'Minimum current(A)');\n",
+"Iavg=(Imax+Imin)/2;//A\n",
+"disp(Iavg,'Average load current(A)');\n",
+"IL=sqrt(1/alfa/T*integrate('(Imin+(Imax-Imin)*t/alfa/T)^2','t',0,alfa*T));//A\n",
+"disp(IL,'RMS load current(A)');\n",
+"Iavg_in=alfa*Iavg;//A\n",
+"disp(Iavg_in,'Average input current(A)');\n",
+"Irms_in=sqrt(1/T*integrate('(Imin+(Imax-Imin)*t/alfa/T)^2','t',0,alfa*T));//A\n",
+"disp(Irms_in,'RMS input current(A)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.7: Find_load_inductance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_7\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=300;//V\n",
+"R=4;//ohm\n",
+"f=250;//Hz\n",
+"ripple=20;//%\n",
+"Iavg=30;//A\n",
+"\n",
+"//Solution :\n",
+"T=1/f;//s\n",
+"E=0;//V\n",
+"Imax_sub_Imin=ripple/100*Iavg;//A\n",
+"L=V/Imax_sub_Imin/R/f;//H\n",
+"disp(L,'Load Inductance(H)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.8: Find_the_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_8\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"Ra=0.5;//ohm\n",
+"L=16/1000;//H\n",
+"V=200;//V\n",
+"E=100;//V\n",
+"Imin=10;//A\n",
+"t_off=2/1000;//s\n",
+"\n",
+"//Solution :\n",
+"i=(V-E)/Ra*[1-exp(-Ra*t_off/L)]+Imin*exp(-Ra*t_off/L);//A\n",
+"disp(i,'Current at instant of turn off(A)');\n",
+"t=5/1000;//s\n",
+"i_dash=i*exp(-Ra*t/L);//A\n",
+"disp(i_dash,'Current 5 ms after turn off(A)');\n",
+"//Answer is wrong in the book."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.9: Speed_of_motor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 4_9\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=220;//V\n",
+"N_NoLoad=1000;//rpm\n",
+"alfa=0.6;//duty cycle\n",
+"I=20;//A\n",
+"Ra=1;//ohm\n",
+"\n",
+"//Solution :\n",
+"Eb1=V;//V////at no load\n",
+"Vin=alfa*V;//V\n",
+"Eb2=Vin-I*Ra;//V\n",
+"N=N_NoLoad*Eb2/Eb1;//rpm\n",
+"disp(N,'Speed of the motor(rpm)');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Introduction_to_Electric_Drives_by_V_Singhal/6-Control_of_DC_drives.ipynb b/Introduction_to_Electric_Drives_by_V_Singhal/6-Control_of_DC_drives.ipynb
new file mode 100644
index 0000000..99d2bf5
--- /dev/null
+++ b/Introduction_to_Electric_Drives_by_V_Singhal/6-Control_of_DC_drives.ipynb
@@ -0,0 +1,161 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 6: Control of DC drives"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.1: Proper_size_of_motor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 6_1\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"hp=[50 100 150 120 0];//hp\n",
+"t=[20 20 10 20 15];//seconds\n",
+"\n",
+"//Solution :\n",
+"hp_rms_t=0;//initializing\n",
+"for i=1:5\n",
+"    hp_rms_t=hp_rms_t+(hp(i)^2*t(i));//hp\n",
+"end\n",
+"hp_rms=sqrt(hp_rms_t/sum(t));//hp\n",
+"disp(hp_rms,'Required hp(rms)');\n",
+"disp('Motor size should be 100 hp');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.2: Thermal_time_constant_and_temperature_rise.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 6_2\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"P=30;//kW\n",
+"theta1=30;//degree C\n",
+"t1=40;//minutes\n",
+"theta2=45;//degree C\n",
+"t2=80;//minutes\n",
+"t2=2*t1;//minutes\n",
+"Loss_fl=2;//kW\n",
+"Loss_Cu=2.5;//kW\n",
+"\n",
+"//Solution :\n",
+"//theta1=theta_f*(1-exp(-t1/T));\n",
+"//let exp(-t1/T)=a\n",
+"a=poly(0,'a');\n",
+"polynomial=(1-a^2)*(theta1/theta2)-1+a;\n",
+"a=roots(polynomial)\n",
+"a=a(2);\n",
+"T=-t1/log(a);//s\n",
+"disp(T,'Thermal time constant(minutes)');\n",
+"theta_f=theta1/(1-exp(-t1/T));\n",
+"disp(theta_f,'Final temperature rise(degree C)');\n",
+"alfa=Loss_fl/Loss_Cu;\n",
+"t=20;//minutes\n",
+"rating=P*sqrt((1+alfa)/(1-exp(-t/T))-alfa);//kW\n",
+"disp(rating,'20 minute rating of motor(kW)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.3: Field_current.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example 6_3\n",
+"clc;\n",
+"clear;close;\n",
+"\n",
+"//Given data: \n",
+"V=230;//V\n",
+"f=50;//Hz\n",
+"alfa=0;//degree\n",
+"Rf=200;//ohm\n",
+"Ra=0.3;//ohm\n",
+"T=50;//N-m\n",
+"N=900;//rpm\n",
+"Kv=0.8;//V/A-rad/s\n",
+"Kt=0.8;//N-m/A^2\n",
+"\n",
+"//Solution :\n",
+"Vm=V*sqrt(2);//V\n",
+"Vf=2*Vm/%pi;//V\n",
+"If=Vf/Rf;//A\n",
+"disp(If,'Field current(A)');\n",
+"Ia=T/(Kt*If);//A\n",
+"omega=(2*%pi/60)*N;//radian/s\n",
+"Eb=Kv*omega*If;//V\n",
+"Va=Eb+Ia*Ra;//V\n",
+"alfa_a=acosd(Va/(Vm/%pi)-1);//degree\n",
+"disp(alfa_a,'Firing angle of armture circuit(degree)');\n",
+"Pout=Va*Ia;//W\n",
+"I_in=sqrt(2/(2*%pi)*integrate('Ia^2','t',alfa_a*%pi/180,%pi));//A\n",
+"VA_in=V*I_in;//VA\n",
+"pf_in=Pout/VA_in;//lagging\n",
+"disp(pf_in,'Input power factor(lagging)');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
-- 
cgit