diff options
Diffstat (limited to '3760/CH4/EX4.42')
| -rw-r--r-- | 3760/CH4/EX4.42/Ex4_42.sce | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/3760/CH4/EX4.42/Ex4_42.sce b/3760/CH4/EX4.42/Ex4_42.sce new file mode 100644 index 000000000..8952674cd --- /dev/null +++ b/3760/CH4/EX4.42/Ex4_42.sce @@ -0,0 +1,16 @@ +clc;
+N=1000; // speed of dc series motor
+v=250; // supply from mains
+i=50; // current drawn from mains
+r=0.6; // armature + field resistance
+rg=4.4; // additional resistance
+// field flux is proportional to armature current
+Ea1=v-i*r; // counter EMF at 1000 rpm
+// Ea2=v-(n2/20)*(r+rg) where Ea2 is counter EMf at speed n2 . taking ratio of Ea2/Ea1 we obtain a quadratic equation in n2 whose terms are given by
+t1=(Ea1*i)/N;
+t2=(N*i)*((r+rg)/(N/i));
+t3=-(N*i*v);
+p=[ t1 t2 t3];
+n=roots(p);
+printf('New speed of motor is %f rpm',ceil(n(2)));
+
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