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diff --git a/3731/CH6/EX6.11/Ex6_11.sce b/3731/CH6/EX6.11/Ex6_11.sce new file mode 100644 index 000000000..5a3b1ed97 --- /dev/null +++ b/3731/CH6/EX6.11/Ex6_11.sce @@ -0,0 +1,50 @@ +//Chapter 6:Induction Motor Drives +//Example 11 +clc; + +//Variable Initialization + +//Ratings of the star connected squirrel Induction motor are same as that of Ex-6.9 +f=50 // frequency in HZ +Vl=400 // line voltage in V +P=4 // number of poles +N=1370 // rated speed + +//Parameters referred to the stator +Xr_=3.5 // rotor winding reactance in ohm +Xs=Xr_ // stator winding reactance in ohm +Rr_=3 // resistance of the rotor windings in ohm +Rs=2 // resistance of the stator windings in ohm + +//Solution +Ns=120*f/P //synchronous speed +N1=Ns-N //increase in speed from no load to full torque rpm +Wms=2*%pi*Ns/60 //synchronous speed +s=(Ns-N)/Ns //full load slip +D=Ns-N //drop in speed from no load to full load torque at 50 Hz + +//(i)When the frequency is 30 Hz and 80% of full load torque +f1=30 //given frequency in Hz +d=D*0.8 //drop in speed from no load to 80% full load torque +Ns1=120*f1/P //synchronous speed at the given frequency f1=30 Hz +N1=Ns1-d //required motor speed + +//(ii)When the speed is 1000 rpm for a full load torque +N2=1000 //given speed in rpm +Ns2=N2+D //synchronous speed +f2=P*Ns2/120 //required frequency + +//When the speed is 1100 rpm and the frequency is 40 Hz +N3=1100 //given speed in rpm +f3=40 //given frequency in Hz +Ns3=120*f3/P //synchronous speed at the given frequency f1=40 Hz +D1=Ns3-N3 //drop in speed from no load to N1=1100 rpm +x=(Rs+Rr_/s)**2+(Xs+Xr_)**2 +Tf=(3/Wms)*(Vl/sqrt(3))**2*(Rr_/s)/x //full load torque +T1=D1/D*Tf //required torque + + +//results +mprintf("(i)Hence the required motor speed is :%d rpm",N1) +mprintf("\n(ii)Hence the required frequency is :%.2f Hz",f2) +mprintf("\n(iii)Hence the required torque is :%.2f N-m",T1) |