1 files changed, 24 insertions, 0 deletions
diff --git a/3760/CH4/EX4.28/Ex4_28.sce b/3760/CH4/EX4.28/Ex4_28.sce
new file mode 100644
index 000000000..724f97ad8
--- /dev/null
+++ b/3760/CH4/EX4.28/Ex4_28.sce
@@ -0,0 +1,24 @@
+clc;
+//Armature reaction is neglected
+Vt=220;//output voltage
+Ra=0.2;//armature circuit resistance
+Rf=110;//field circuit resistance
+n1=1500;//speed of rotor at no load
+Il1=5;//curent drawn by motor in ampere at no load & 1500 rpm
+Il2=52;//curent drawn by motor in ampere at rated load & rated voltage
+If=Vt/Rf;//shunt field current
+Ia1=Il1-If;//armature current at no load
+Ea1=Vt-Ia1*Ra;//counter emf at no load
+Pr=Ea1*Ia1;//rotational losses at no load
+//Rotational losses at full load & no load are same
+Ia2=Il2-If;//armature current at full load
+Ea2=Vt-Ia2*Ra;//counter emf at full load
+Pem=Ia2*Ea2;//electromagnetic power
+//Here phi_1(no load flux)=phi_2(full load flux), because the field current is constant & effect of AR is neglected.
+//Ea1/Ea2=(n1*phi_1)/(n2*phi_2);where n1 & n2 are speed of rotor at no load & full load respectively.
+n2=fix((n1*Ea2)/(Ea1));
+Psh=Pem-Pr;//shaft power
+Wm=(2*%pi*n2)/60;//angular velocity of shaft at full load
+Tsh=Psh/Wm//shaft torque
+printf('The motor speed is %f rpm.\n',n2);
+printf('Rated shaft torque is %f Nm.',Tsh);