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//Chapter 6:Induction Motor Drives
//Example 1
clc;
//Variable Initialization
//Ratings of the Y-connected induction motor
f=50 // frequency in HZ
Vl=440 //line voltage in V
P=6 // number of poles
N=950 //speed in rpm
//Parameters referred to the stator
Xr_=1.2 // rotor winding reactance in ohm
Rr_=0.4 // resistance of the rotor windings in ohm
Rs=0.5 // resistance of the stator windings in ohm
Xs=Xr_ // stator winding reactance in ohm
Xm=50 // no load reactance in ohms
//Solution
Ns=120*f/P //synchronous speed in rpm
s=(Ns-N)/Ns //full load slip
x=sqrt((Rs+Rr_/s)**2+(Xs+Xr_)**2) //total impedance
Ir_=(Vl/sqrt(3))/x //full load rotor current
angle=-atan((Xs+Xr_)/(Rs+Rr_/s)) //angle in radian
Ir_=Ir_*(cos(angle)+sin(angle)*%i) //full load rotor current in rectangular form
Im=Vl/sqrt(3)/Xm*(-%i) //magnetizing current
Is=Ir_+Im //full load current
Zf=Rs+Xs*%i+%i*Xm*(Rr_/s+%i*Xr_)/(Rr_/s+%i*(Xr_+Xm))
Zb=Rs+Xs*%i+%i*Xm*(Rr_/(2-s)+%i*Xr_)/(Rr_/(2-s)+%i*(Xr_+Xm))
Z=Zf+Zb
I=(Vl/sqrt(3))/abs(Z) //motor current
Wms=2*%pi*Ns/60
//Torque due to positive sequence
Tp=(1/Wms)*(3*I**2*Xm**2*Rr_/s)/((Rr_/s)**2+(Xr_+Xm)**2)
//Torque due to negative sequence
Tn=-(1/Wms)*(3*I**2*Xm**2*Rr_/(2-s))/((Rr_/(2-s))**2+(Xr_+Xm)**2)
T=Tp+Tn //net torque
Wm=Wms*(1-s) //rated speed in in rad/sec
Tl=0.0123*Wm**2 //required torque of the load
//Results
var=phasemag(Is)
mprintf("Full load motor current Is:%.1f %.1f ° A",abs(Is),var)
mprintf("\nTp:%.2f N-m",Tp)
mprintf("\nTn:%.3f N-m",Tn)
mprintf("\n\nSince I:%.2f A and N:%d rpm",I,N)
mprintf("\nAnd I:%.2f A< Is %.2f A, the motor will run safely",I,abs(Is))
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