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| author | priyanka | 2015-06-24 15:03:17 +0530 |
|---|---|---|
| committer | priyanka | 2015-06-24 15:03:17 +0530 |
| commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
| tree | ab291cffc65280e58ac82470ba63fbcca7805165 /1938/CH3/EX3.20/3_20.sce | |
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initial commit / add all books
Diffstat (limited to '1938/CH3/EX3.20/3_20.sce')
| -rwxr-xr-x | 1938/CH3/EX3.20/3_20.sce | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/1938/CH3/EX3.20/3_20.sce b/1938/CH3/EX3.20/3_20.sce new file mode 100755 index 000000000..db92c18bb --- /dev/null +++ b/1938/CH3/EX3.20/3_20.sce @@ -0,0 +1,22 @@ +clc,clear
+printf('Example 3.20\n\n')
+
+V=225,I=10
+dN=1030 - 970 //given
+t_1=40 //time with no excitation
+t_2=9// time with full excitation and armature supporting an extra load of 10 A at 219 V
+t_3=20 //time with full exciation
+
+W_dash = V*I //additional loss
+W_s= W_dash *(t_2/(t_3-t_2)) //total stray losses
+N=1000//Speed in rpm
+//Using W_s = (2*pi/60)^2 * I *N *dN / t_3 where W_s is stray losses
+I= W_s*(t_3/dN)*(30/%pi)^2/N //moment of inertia
+W_m=W_s*(t_3/t_1) //mechanical losses
+iron_losses=W_s - W_m
+
+printf('(i)The moment of inertia of armature is %.2f kg-m^2\n',I)
+printf('(ii)Iron loss= %.2f W\n',iron_losses)
+printf('(iii)Mechanical losses at 1000 rpm mean speed is %.2f W',W_m)
+
+printf('\n\nNoteworthy points:\n(1)When there is no excitation and armature is slowed down , its K.E. is used to overcome mechanical mechanical losses only since there will be no iron loss as there is no flux.\n(2)When there is excitation provided then K.E. is used to supply mechanical as well as iron losses together called stray losses ')
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