initial commit / add all books

1 files changed, 33 insertions, 0 deletions

diff --git a/3760/CH4/EX4.40/Ex4_40.sce b/3760/CH4/EX4.40/Ex4_40.sce
new file mode 100644
index 000000000..3976a0aba
--- /dev/null
+++ b/3760/CH4/EX4.40/Ex4_40.sce
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+clc;

+v=200; // rated voltage of shunt motor

+i=22; // rated current of dc shunt motor

+n1=1000; // speed at which motor is running

+rf=100; // field resistance

+ra=0.1; // armature resistance

+n2=800; // reduced speed at which motor is to run

+iF=v/rf; // field current

+ia=i-iF; // armature current

+disp('case a');

+// load torque is independent of speed

+Ea1=v-ia*ra; // counter EMF at 1000 rpm

+rg=(v-ia*ra-(n2*Ea1)/n1)/ia; 

+printf('Additional resistance inserted in armature circuit is %f ohms\n',rg);

+printf('Loss in additional resistance is %f W\n',ia^2*rg);

+disp('case b');

+// load torque is directly proportional to speed

+ia2=(n2/n1)*ia; // armature current at 800 rpm

+rg=(v-ia2*ra-(n2*Ea1)/n1)/ia2; 

+printf('Additional resistance inserted in armature circuit is %f ohms\n',rg);

+printf('Loss in additional resistance is %f W\n',ia2^2*rg);

+disp('case c');

+// load torque varies as the square of speed

+ia2=(n2/n1)^2*ia; // armature current at 800 rpm

+rg=(v-ia2*ra-(n2*Ea1)/n1)/ia2; 

+printf('Additional resistance inserted in armature circuit is %f ohms\n',rg);

+printf('Loss in additional resistance is %f W\n',ia2^2*rg);

+disp('case d');

+// load torque varies as the cube of speed

+ia2=(n2/n1)^3*ia; // armature current at 800 rpm

+rg=(v-ia2*ra-(n2*Ea1)/n1)/ia2; 

+printf('Additional resistance inserted in armature circuit is %f ohms\n',rg);

+printf('Loss in additional resistance is %f W\n',ia2^2*rg);