1 files changed, 25 insertions, 0 deletions
diff --git a/1938/CH2/EX2.38/2_38.sce b/1938/CH2/EX2.38/2_38.sce
new file mode 100755
index 000000000..571e98e71
--- /dev/null
+++ b/1938/CH2/EX2.38/2_38.sce
@@ -0,0 +1,25 @@
+clc,clear
+printf('Example 2.38\n\n')
+
+V=250, N_1=1000
+I_L1=25
+R_a=0.2, R_sh=250 //armature and shunt field resistance
+V_brush= 1 //voltage drop due to brushes
+
+I_sh1 = V/R_sh
+I_a1= I_L1 - I_sh1
+E_b1= V- I_a1*R_a - 2 *V_brush
+
+//when loaded
+I_L2=50
+I_sh2=I_sh1   //as flux weakensby armature reaction,shunt field current remains same 
+I_a2= I_L2 - I_sh2
+E_b2= V- I_a2*R_a - 2 *V_brush
+
+phi2_by_phi1= 1- (3/100)  //weakens by 3 percent
+N_2= N_1*(E_b2/E_b1)/ phi2_by_phi1   //N (prop.) E_b/phi
+printf('New speed = %.3f rpm',N_2)
+T_1= E_b1*I_a1/(2*%pi*N_1/60)
+T_2= E_b2*I_a2/(2*%pi*N_2/60)
+printf('\nTorque before field weakening = %.4f N-m',T_1)
+printf('\nTorque after  field weakening = %.4f N-m',T_2)