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diff --git a/3731/CH5/EX5.18/Ex5_18.sce b/3731/CH5/EX5.18/Ex5_18.sce new file mode 100644 index 000000000..342b13451 --- /dev/null +++ b/3731/CH5/EX5.18/Ex5_18.sce @@ -0,0 +1,57 @@ +//Chapter 5:Dc Motor Drives +//Example 18 +clc; + +//Variable Initialization + +//The separately excited motor is fed from a circulating dual converter +V=220 // rated voltage in V +N=1500 // rated speed in rpm +Ia=50 // rated current in A +Ra=0.5 // armature resistance in ohms +Vl=165 // line voltage in V +f=50 // frequency of the source voltage in Hz + +//Solution +E=V-Ia*Ra //back emf at the rated speed +Vm=Vl*sqrt(2) //peak voltage + +//(i)During motoring operation when the speed is 1000 rpm and at rated torque +N1=1000 //speed of the motor in rpm +E1=N1/N*E //back emf at the given speed N1 +Va=E1+Ia*Ra //terminal voltage at the given speed N1 +alpha_A=acos(%pi/3*Va/Vm) +alpha_A=alpha_A*180/%pi//required converter firing angle in degrees +alpha_B=180-alpha_A + +//(ii)During braking operation when the speed is 1000 rpm and at rated torque +N1=1000 //speed of the motor in the book is given as 100 rpm which is wrong +E1=N1/N*E //back emf at the given speed N1 +Va=E1-Ia*Ra //terminal voltage at the given speed N1 +alpha_A1=acos(%pi/3*Va/Vm) +alpha_A1=alpha_A1*180/%pi//required converter firing angle in degrees +alpha_B1=180-alpha_A1 + +//(iii)During motoring operation when the speed is -1000 rpm and at rated torque +N1=-1000 //speed of the motor in rpm +E1=N1/N*E //back emf at the given speed N1 +Va=E1-Ia*Ra //terminal voltage at the given speed N1 +alpha_A2=acos(%pi/3*Va/Vm) +alpha_A2=alpha_A2*180/%pi//required converter firing angle in degrees +alpha_B2=180-alpha_A2 + +//(iv)During braking operation when the speed is -1000 rpm and at rated torque +N1=-1000 //speed of the motor in the book it is given as 100 rpm which is wrong +E1=N1/N*E //back emf at the given speed N1 +Va=E1+Ia*Ra //terminal voltage at the given speed N1 +alpha_A3=acos(%pi/3*Va/Vm) +alpha_A3=alpha_A3*180/%pi//required converter firing angle in degrees +alpha_B3=180-alpha_A3 + +//Results +mprintf("\n(i)Hence the required firing angle is :%.1f °",alpha_B) +mprintf("\n(ii)Hence the required firing angle is :%.1f °",alpha_B1) +mprintf("\n(iii)Hence for negative speed during motoring operation the required firing angles are :") +mprintf("\nalpha_A :%.1f ° and alpha_B :%.1f °",alpha_A2,alpha_B2) +mprintf("\n(iv)Hence for negative speed during braking operation the required firing angles are :") +mprintf("\nalpha_A :%.1f ° and alpha_B :%.1f °",alpha_A3,alpha_B3) |