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+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.6
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=2;//number of poles
+f=60;//frequency in hertz
+Xeq=4;//inductive reactance in ohm
+R1=0.2;//stator resistance in ohm
+R2=0.3;//rotor resistance reffered to stator in ohm
+Td=60;//driving constant load torque in Nm
+n=3500;//speed of the motor in rpm
+a=120;//constant value
+ns=(a*f)/p;//synchronous speed in rpm
+mprintf("\nTo compute the maximum frequency of the supply voltage:")
+Tmax=Td;
+rpss=ns/60;
+omegas=(2*%pi*rpss);
+fmax=sqrt((V^2*f^2)/(Tmax*2*omegas*4));
+mprintf("\nThe maximum frequency of the supply voltage is %f Hz",fmax)
+mprintf("\nTo calculate the motor current at f and fmax:")
+s=(ns-n)/ns;//slip at 60Hz
+Vs=V/sqrt(3);
+I2=Vs/sqrt((R1+(R2/s))^2+Xeq^2);
+mprintf("\nThe motor current at 60 Hz is %f A",I2)
+Xeqmax=(fmax/f)*Xeq;
+smax=R2/sqrt(R1^2+Xeqmax^2);
+nmax=((a*fmax)/p)*(1-smax);
+I2max=Vs/sqrt((R1+(R2/smax))^2+Xeqmax^2);
+mprintf("\nThe motor current at 67.7Hz is %f A",I2max)
+mprintf("\nTo calculate the power delivered to the load at f and fmax:")
+rps=n/60;
+omega=(2*%pi*rps);
+Pd=Td*omega;//developed power at 60Hz
+Pd=Pd*10^(-3);//developed power in kilowatt
+mprintf("\nThe power delivered to the load at 60Hz is %f Kw",Pd)
+rpsmax=nmax/60;
+omegamax=(2*%pi*rpsmax);
+Pdmax=Td*omegamax;//developed power at 67.7Hz
+Pdmax=Pdmax*10^(-3);//developed power in kilowatt
+mprintf("\nThe power delivered to the load at 67.7Hz is %f Kw",Pdmax)