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+// chapter 14
+// example 14.12
+// Determine the range of frequencies of the chopper
+// page-893
+clear;
+clc;
+// given
+I=80; // in A
+E=480; // in V
+N=960; // in rpm
+Ra=0.25; // in ohm (armature resistance)
+Rf=120; // in ohm (field resistance)
+N1=400, N2=750; // in rpm (range of speed)
+Ton=3; // in ms
+Ef=480; // in V
+// calculate
+Ton=Ton*1E-3; // changing unit from ms to s
+If=E/Rf; // calculation of field current
+Ia=I-If; // calculation of armature current
+Eb=E-Ia*Ra; // calculation of back emf
+Eb1=(N1/N)*Eb; // calculation of back emf corresponding to N1=400 rpm
+Ea1=Eb1+Ia*Ra; // calculation of terminal voltage corresponding to N1=400 rpm
+T1=(E/Ea1)*Ton; // calculation of chopping period corresponding to N1=400 rpm
+F1=1/T1; // calculation of frequency corresponding to N1=400 rpm
+Eb2=(N2/N)*Eb; // calculation of back emf corresponding to N2=400 rpm
+Ea2=Eb2+Ia*Ra; // calculation of terminal voltage corresponding to N2=400 rpm
+T2=(E/Ea2)*Ton; // calculation of chopping period corresponding to N2=400 rpm
+F2=1/T2; // calculation of frequency corresponding to N2=400 rpm
+printf("\n\nThe range of frequencies of the chopper is \t %.2f Hz <= f <= %.2f Hz",F1,F2);
+// Note: The answer vary slightly due to precise calculations
+\ No newline at end of file