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// Example 9.11
// Determine (a) Equivalent armature resistance (b) Synchronous reactance
// (c) Short-circuit ratio
// Page 377
clc;
clear;
close;
// Given data
Vdc=10.35; // DC voltage
Idc=52.80; // DC current
VOCph=240/sqrt(3); // Open-circuit phase voltage
ISCph=115.65; // Short-circuit phase current
P=50000;
V=240; // Supply voltage
// (a) Equivalent armature resistance
Rdc=Vdc/Idc; // DC resistance
Rgamma=Rdc/2;
Ra=1.2*Rgamma; // Armature resistance
// (b) Synchronous reactance
Zs= VOCph/ISCph; // Synchronous impedance/phase
Xs=sqrt(Zs^2-Ra^2);
// (c) Short-circuit ratio
Sbase=P/3; // Power/phase
Vbase=V/sqrt(3); // Voltage/phase
Zbase=Vbase^2/Sbase;
Xpu=Xs/Zbase; // Per unit synchronous reactance
SCR=1/Xpu; // Short-circuit ratio
// Display result on command window
printf("\n Equivalent armature resistance = %0.4f Ohm ",Ra);
printf("\n Synchronous reactance = %0.4f Ohm ",Xs);
printf("\n Short-circuit ratio = %0.3f ",SCR);
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