From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001
From: prashantsinalkar
Date: Tue, 10 Oct 2017 12:27:19 +0530
Subject: initial commit / add all books

---
 3760/CH4/EX4.42/Ex4_42.sce | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 3760/CH4/EX4.42/Ex4_42.sce

(limited to '3760/CH4/EX4.42')

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)));
+   
-- 
cgit