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// Example 5.8
// Determine (a) Expected minimum locked-rotor torque (b) Repeat (a) when
// voltage and frequency dropped to 230V and 58Hz
// Page No. 193
clc;
clear;
close;
// Given data
HPrated=75; // Rated horsepower
nrated=1750; // Rated speed
V1=240; // Rated voltage
V2=230; // Voltage after drop
F1=60; // Rated frequency
F2=58; // Frequency after drop
// (a) Expected minimum locked-rotor torque
Trated=5252*HPrated/nrated; // Rated torque
Tlr=Trated*1.2; // Minimum locked-rotor torque is 120% rated
// (b) Expected minimum locked-rotor torque when voltage and frequency dropped
// to 230V and 58Hz
Tlr2=Tlr*((V2/F2)^2)*((F1/V1)^2);
// Display result on command window
printf("\n Expected minimum locked-rotor torque = %0.0f lb-ft",Tlr);
printf("\n Expected minimum locked-rotor torque after drop = %0.0f lb-ft",Tlr2);
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