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+//Chapter 5:Dc Motor Drives
+//Example 20
+clc;
+
+//Variable Initialization
+
+//Ratings of the separately excited motor when it is operated in dynamic breaking
+V=230    // rated voltage in V
+N=960    // rated speed in rpm
+Ia=200   // rated current in A
+Ra=0.02  // armature resistance in ohms
+Vs=230   // source voltage in V
+Rb=2     // braking resistance in ohm
+
+//Solution
+//When the motor speed is 600 rpm and the braking torque is twice the rated value
+Ia1=2*Ia     //torque is directly proportional to current
+N1=600       //speed of the motor in rpm
+E=V-Ia*Ra    //back emf
+E1=N1/N*E
+x=E1/Ia1-Ra  //x=(1-delta)*Rb
+y=x/Rb       //y=1-delta
+delta=1-y    //duty ratio
+
+//(ii)If the duty ratio is 0.6 and and the braking torque is twice the rated value
+delta1=0.6  //duty ratio
+Ia1=2*Ia   //torque is directly proportional to current
+E1=Ia1*((1-delta1)*Rb+Ra)   //back emf
+N1=E1/E*N
+
+
+//Results 
+mprintf("(i)Duty ratio is :%.2f",delta)
+mprintf("\n(ii)Hence the motor speed is :%.1f rpm",N1)