From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001
From: prashantsinalkar
Date: Tue, 10 Oct 2017 12:27:19 +0530
Subject: initial commit / add all books

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+// Example 6.2
+// Determine (a) Capacitance required in series with the auxillary winding 
+// in order to obtain a 90 degree phase displacement between the current in 
+// the main winding and the current in the auxillary winding at locked rotor  
+// (b) Locked rotor torque in terms of the machine constant 
+// Page No. 265
+
+clc;
+clear;
+close;
+
+// Given data
+Zmw=2.00+%i*3.50                // Main winding impedance
+Zaw=9.15+%i*8.40                // Auxillary winding impedance
+VT=120;                         // Transformer voltage
+Xaw=8.40;                       // Auxillary winding reactance
+Raw=9.15;                       // Auxillary winding resistance
+f=60;                           // Frequency
+Tlr=107.1;                      // Original torque
+
+// (a) Capacitance required in series with the auxillary winding 
+// Main winding impedance in polar form
+// Complex to Polar form...
+Zmw_Mag=sqrt(real(Zmw)^2+imag(Zmw)^2);      // Magnitude part
+Zmw_Ang=atan(imag(Zmw),real(Zmw))*180/%pi;  // Angle part

+
+// Auxillary winding impedance in polar form
+// Complex to Polar form...
+Zaw_Mag=sqrt(real(Zaw)^2+imag(Zaw)^2);      // Magnitude part
+Zaw_Ang=atan(imag(Zaw),real(Zaw))*180/%pi;  // Angle part

+
+// Main winding current
+Imw_Mag=VT/Zmw_Mag;                 // Main winding current magnitude
+Imw_Ang=0-Zmw_Ang;                  // Main winding current angle
+
+// Auxillary winding current
+Iaw_Mag=VT/Zaw_Mag;                 // Auxillary winding current magnitude
+Iaw_Ang=0-Zaw_Ang;                  // Auxillary winding current angle
+
+Theta_awi=90-60.26;               // Required phase angle
+Theta_awz=-Theta_awi;
+
+Xc=Xaw-Raw*tand(Theta_awz);       // Capacitive reactance
+
+C=1/2*%pi*f*Xc;                     // Required capacitance
+
+
+// (b) Locked rotor torque in terms of the machine constant 
+Zawnew=Raw+%i*Xaw-%i*Xc;            // Auxillary winding impedance
+// Complex to Polar form...
+Zawnew_Mag=sqrt(real(Zawnew)^2+imag(Zawnew)^2);      // Magnitude part
+Zawnew_Ang=atan(imag(Zawnew),real(Zawnew))*180/%pi;  // Angle part

+
+Iawnew_Mag=VT/Zawnew_Mag;           // Auxillary winding current magnitude
+Iawnew_Ang=0-Zawnew_Ang;            // Auxillary winding current magnitude
+
+Tlenew=Imw_Mag*Iawnew_Mag*sind(90);
+
+// Percent change increase in locked rotor torque 
+PI=(Tlenew-Tlr)/Tlr*100;
+
+
+// Display result on command window
+printf("\n Required capacitance = %0.1f microF ",C);
+printf("\n Percent increase in locked rotor torque = %0.0f Percent",PI);
+
+//Note: Capacitor computation is wrong in the book
-- 
cgit