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//============================================================================
//Chapter 7 Example 8
clc;
clear all;
//variable declaration
theta1 =1; //pressure coil phase angle in °
theta2 =2; //pressure coil phase angle in °
P1 = 700; //wattmeter reading in W
P2 = 620; //wattmeter reading in W
V = 240; //voltage in V
//calculations
x = P1/P2;
//P1 =P*cos(theta2)*cos(phi-theta2)/cos(phi)
//P2 = P*cos(theta1)*cos(phi-theta1)/cos(phi)
//P1/P2 = cos(theta2)*cos(phi-theta2)/cos(phi)/cos(theta1)*cos(phi-theta1)/cos(phi)
//x = cos(theta2)*cos(phi-theta2)/cos(phi)/cos(theta1)*cos(phi-theta1)/cos(phi)
//x = (cos(theta2)/cos(theta1))*(cos(phi-theta2)/cos(phi-theta1))
//x = y*(cos(phi-theta2)/cos(phi-theta1))
//(cos(phi-theta2)/cos(phi-theta1)) = x/y
y = (cos(theta2*%pi/180)/cos(theta1*%pi/180));
z = x/y;
//(cos(phi-theta2)/cos(phi-theta1)) = ((cos(thet2*%pi/180))*cos(phi))+(sin(thet2*%pi/180))*sin(phi))/((cos(theta1*%pi/180))*cos(phi))+(sin(thet1*%pi/180))*sin(phi))
//z = ((cos(thet2*%pi/180))*cos(phi))+(sin(thet2*%pi/180))*sin(phi))/((cos(theta1*%pi/180))*cos(phi))+(sin(thet1*%pi/180))*sin(phi))
t = ((z*cos(theta1*%pi/180))-(cos(theta2*%pi/180)))/((sin(theta2*%pi/180))-(z*sin(theta1*%pi/180)));
phi = (atan(t))*180/%pi;
pf = cos(phi*%pi/180);
C = (phi-theta2)
c = cos(C*%pi/180);
a = (cos(theta2*%pi/180));
b = a*c;
B = P1*pf;
P = B/b;
I = P/(V*pf);
//result
mprintf("actual power = %3.3f W",P);
mprintf("\ncurrent drawn = %3.2f A",I);
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