%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  sepgen.m - plots terminal characteristic for separately 
%             excited dc generator. Armature reaction neglected.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clear; clf;
VtR=600;      % Rated terminal voltage
PR=60e03;     % Rated output power
Ra=0.25;      % Armature resistance
IaR=PR/VtR;   % Rated output current
load eif      % Load stored OCC
m=length(eif); npts=200;
E=eif(1:m,1); If=eif(1:m,2);
% Determine E & If at rated condition
IfR=interp1( E, If, VtR+IaR*Ra); ER=interp1(If, E, IfR);
Ia=linspace(0,1.5*IaR,npts);
Vt=ER-Ia(1:npts)*Ra;
plot(0,0,Ia,Vt,IaR,VtR,'o'); grid;
title('Separately excited dc generator');
xlabel('Load current, A'); ylabel('Terminal voltage, V');