1 files changed, 28 insertions, 0 deletions
diff --git a/3760/CH4/EX4.38/Ex4_38.sce b/3760/CH4/EX4.38/Ex4_38.sce
new file mode 100644
index 000000000..3c16a651c
--- /dev/null
+++ b/3760/CH4/EX4.38/Ex4_38.sce
@@ -0,0 +1,28 @@
+clc;
+v=230; // rated voltage of dc motor
+p=10000; // rated power of dc motor
+rf=115; // field resistance
+ra=0.348; // net armature resistance
+ifs=v/rf; // shunt field current
+ia=(p/v)-ifs; // rated armature current
+disp('case a');
+rx1=(v/(2*ia))-ra; 
+printf('External resistance required at the time of starting is %f ohms\n',rx1);
+disp('case b');
+Ea1=v-ia*(rx1+ra); // counter emf at stud 1
+r2=(v-Ea1)/(2*ia); // resistance when handle is moved to 2nd stud
+rx2=r2-ra; // external resistance 
+rc=rx1-rx2; 
+printf('Resistance that must be cut out in first step is %f ohms\n',rc);
+disp('case c');
+Ea2=v-ia*rc; // counter emf at stud 2
+r3=(v-Ea2)/(2*ia); // resistance when handle is moved to 3rd stud 
+rc=rc-r3; 
+printf('Resistance that must be cut out in second step is %f ohms\n',rc);
+disp('case d');
+Ea3=v-ia*rc; // counter emf at stud 3
+r4=(v-Ea3)/(2*ia); // resistance when handle is moved to 4th stud 
+rc=rc-r4; 
+printf('Resistance that must be cut out in third step is %f ohms\n',rc);
+disp('Total number of steps is 3');
+