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// Example 11.6
// Determine (a) Torque developed when operating at rated speed (b) Developed
// torque required at half rated speed (c) Armature voltage required for half
// rated speed
// Page No. 460
clc;
clear;
close;
// Given data
VT=750; // Voltage value of motor
Nf=1231; // Turns per pole of the shunt motor
Ra=0.00540; // Armature resistance
RIPcw=0.00420; // Interpole winding resistance
N=955; // Speed of shunt motor
Ia1=1675; // Armature current
// (a) Torque developed when operating at rated speed
Racir=Ra+RIPcw;
Ea=VT-Ia1*Racir;
Pmech=Ea*Ia1;
TD=Pmech*5252/N/746;
// (b) Developed torque required at half rated speed
T2=TD*(0.5*N/N)^2;
// (c) Armature voltage required for half rated speed
Ia2=T2*Ia1/TD;
V2=(0.5*N/N)*(VT-Ia1*Racir) + Ia2*Racir ;
// Shaft load is adjusted to value that limits the armature current to 115 % of rated current
//Display result on command window
printf("\n Torque developed when operating at rated speed = %0.1f lb-ft ",TD);
printf("\n Developed torque required at half rated speed = %0.1f lb-ft ",T2);
printf("\n Armature voltage required for half rated speed = %0.1f V ",V2);
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