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+//Chapter 6:Induction Motor Drives
+//Example 3
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=6            // number of poles
+
+//Parameters referred to the stator
+Xr_=2         // rotor winding reactance in ohm
+Xs=Xr_        // stator winding reactance in ohm
+Rr_=1         // resistance of the rotor windings in ohm
+Rs=Rr_        // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed in rpm
+Wms=2*%pi*Ns/60        
+
+//(i)
+Sm=-Rr_/sqrt(Rs**2+(Xs+Xr_)**2)   //slip at maximum torque
+x=sqrt((Rs+Rr_/Sm)**2+(Xs+Xr_)**2)
+Ir_=(Vl/sqrt(3))/x        //current at maximum torque 
+Tmax=(1/Wms)*3*Ir_**2*Rr_/Sm   //maximum torque
+N=(1-Sm)*Ns                    //range of speed
+
+//(ii)an overhauling torque of 100Nm
+Tl=100   //overhauling torque in Nm
+// Tl=(3/Wms)*(Vl**2*Rr_/s)/y
+// where y=(Rs+Rr_/s)**2+(Xs+Xr_)**2
+a=(1/Wms)*(Vl**2*Rr_)/(-Tl)    //a=s*(Rs+Rr_/s)**2+(Xs+Xr_)**2
+a = 17
+b = 17.3
+c = 1
+
+//Discriminant
+d = (b**2) - (4*a*c)
+
+// find two solutions
+s1 = (-b-sqrt(d))/(2*a)
+s2 = (-b+sqrt(d))/(2*a)
+
+N2=(1-s2)*Ns           //motor speed and we neglect s1 
+
+//slight difference in the answer due to accuracy
+
+//(iii)when a capacitive reactance of 2 ohm is inserted in each phase stator
+Xc=2      //reactance of the capacitor in ohms
+Sm=-Rr_/sqrt(Rs**2+(Xs+Xr_-Xc)**2)   //slip at maximum torque 
+x=sqrt((Rs+Rr_/Sm)**2+(Xs+Xr_-Xc)**2)
+Ir_=(Vl/sqrt(3))/x        //current at maximum torque 
+Tmax_=(1/Wms)*3*Ir_**2*Rr_/Sm   //maximum overhauling torque with capacitor
+ratio=Tmax_/Tmax
+
+
+//Results
+mprintf("(i)Maximum overhauling torque that the motor can hold is:%.1f N-m",abs(Tmax))
+mprintf("      \nRange of speed is from %d to %d rpm\n",Ns,abs(N))
+mprintf("\n(ii)Now s*(1+1/s)**2+16s=%d",a)
+mprintf("\n    Or 17s**s+17.3s+1=0")
+mprintf("\nThe solutions for s are %.3f and %.3f\n",s1,s2)
+mprintf("\nTherefore Motor speed is:%d rpm\n",N2)
+//Note :There is a slight difference in the answer due to the decimal place"
+mprintf("\n(iii) Ratio of maximum torque with capacitor and to maximum torque without capacitor is:%.2f",ratio)