From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001
From: priyanka
Date: Wed, 24 Jun 2015 15:03:17 +0530
Subject: initial commit / add all books

---
 608/CH21/EX21.21/21_21.sce | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100755 608/CH21/EX21.21/21_21.sce

(limited to '608/CH21/EX21.21')

diff --git a/608/CH21/EX21.21/21_21.sce b/608/CH21/EX21.21/21_21.sce
new file mode 100755
index 000000000..2cc2c0368
--- /dev/null
+++ b/608/CH21/EX21.21/21_21.sce
@@ -0,0 +1,20 @@
+//Problem 21.21: A 200 V, d.c. shunt-wound motor has an armature resistance of 0.4 ohm and at a certain load has an armature current of 30 A and runs at 1350 rev/min. If the load on the shaft of the motor is increased so that the armature current increases to 45 A, determine the speed of the motor, assuming the flux remains constant.
+
+//initializing the variables:
+Ia1 = 30; // in Amperes
+Ia2 = 45; // in Amperes
+Ra = 0.4; // in ohm
+n1 = 1350/60; // in Rev/sec
+V = 200; // in Volts
+
+//calculation:
+//The relationship E proportional to (Phi*n) applies to both generators and motors. For a motor,
+//E = V - (Ia*Ra)
+E1 =  V - (Ia1*Ra)
+E2 =  V - (Ia2*Ra)
+//The relationship, E1/E2 = Phi1*n1/Phi2*n2,  applies to both generators and motors. Since the flux is constant, Phi1 = Phi2
+Phi2 = Phi1
+n2 = E2*Phi1*n1/(Phi2*E1)
+
+printf("\n\n Result \n\n")
+printf("\n the speed of the motor is %.2f rev/sec ",n2)
\ No newline at end of file
-- 
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