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Diffstat (limited to '3731/CH5/EX5.5/Ex5_5.sce')
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diff --git a/3731/CH5/EX5.5/Ex5_5.sce b/3731/CH5/EX5.5/Ex5_5.sce new file mode 100644 index 000000000..168a12d7e --- /dev/null +++ b/3731/CH5/EX5.5/Ex5_5.sce @@ -0,0 +1,61 @@ +//Chapter 5:Dc Motor Drives +//Example 5 +clc; + +//Variable Initialization + +//Ratings of the DC shunt motor which operated under dynamic braking +Rb=1 //braking resisance in ohms +Ra=0.04 //armature resistance in ohms +Rf=10 //field resistance in ohms +T=400 //load torque in N-m + +//Magnetisation curve at N1 +N1=600 //speed in rpm +If=[2.5,5,7.5,10,12.5,15,17.5,20,22.5,25] //field current in A +E =[25,50,73.5,90,102.5,110,116,121,125,129] //back emf in V + +//Solution +disp(If,"Field current If:in A") +x=(Rb+Rf)/Rb +Ia = If * x //armature current +Wm=2*%pi*N1/60 +Ke_flux=E / Wm //Ke*flux=constant +T=[] +for i=1:10 +T($+1)=(Ke_flux(i))*(Ia(i)) //torque +end +disp(Ke_flux,"Ke_flux :") +disp(T,"Torque :in N-m") + + +//Results + +//Plotting the values of Ke*flux vs If +If=[2.5,5,7.5,10,12.5,15,17.5,20,22.5,25] //field current in A +subplot(2,1,1) +plot(If,Ke_flux,'y') +xlabel('field current I_f') +ylabel('Ke*flux') +title('If vs Ke*flux') +xgrid(2) + +//Plotting the values of T vs If +If=[2.5,5,7.5,10,12.5,15,17.5,20,22.5,25] //field current in A +subplot(2,1,2) +plot(T,If) +xlabel('Torque T') +ylabel('field current I_f') +title('T vs If') +xgrid(2) + + +mprintf("\nFrom the plot we can see that when the torque is 400 N-m, ") +mprintf("\nthe field current is If=19.3 A, and Ke*flux=1.898 when If=19.3 A") +T=400 // braking torque in N-m +If=19.13 // field current in A +Ke_flux=1.898 // Ke*flux +Ia=x*If +E=If*Rf+Ia*Ra //since E=V+Ia*Ra +N2=(E/Ke_flux)*(60/(2*%pi)) //required speed +mprintf("\nHence the required speed in is :%.1f rpm",N2) |