blob: 1915fa0f49698413d86098090f38984ff3562046 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
// Example 5.9
// Determine (a) Shaft r/min (b) Slip
// Page No. 194
clc;
clear;
close;
// Given data
F1=60; // Rated frequency
N=4; // Number of poles
F2=50; // New frequency
ns=1770; // Rated speed
// (a) Shaft r/min
ns60=120*F1/N; // Speed at rated ferquency
ns50=120*F2/N; // Speed at 50 Hz frequency
s60=(ns60-ns)/ns60; // Slip at 60 Hz frequency
// Using eq. (5.16) and by solving..s50=29.251/nr50
// Using eq. (4.3) and solving for nr50 we get the quadratic equation..
// Using various values of quadratic equations, we have
a=1;
b=-1500;
c=43876.5;
r1=(-b+sqrt(b^2-4*a*c))/(2*a); // Root 1
r2=(-b-sqrt(b^2-4*a*c))/(2*a); // Root 2
// Answer 'r2' is not valid
// (b) Slip
s50=(ns50-r1)/ns50;
// Display result on command window
printf("\n Shaft speed = %0.0f r/min",r1);
printf("\n Slip = %0.3f ",s50);
|
