1 files changed, 27 insertions, 0 deletions
diff --git a/3811/CH7/EX7.7/Ex7_7.sce b/3811/CH7/EX7.7/Ex7_7.sce
new file mode 100644
index 000000000..7f08ac482
--- /dev/null
+++ b/3811/CH7/EX7.7/Ex7_7.sce
@@ -0,0 +1,27 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.7
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=2;//number of poles
+fst=60;//frequency in hertz
+f=50;//decreased frequency in Hz
+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
+ns=(120*f)/p;//synchronous speed in rpm
+Vs=V/sqrt(3);
+rps=ns/60;
+omegas=(2*%pi*rps);
+s=(Td*omegas*R2)/V^2;
+n=ns*(1-s);//the new motor speed at 50Hz in rpm
+mprintf("\nThe new motor speed at 50Hz is %f rpm",n)
+I2st=Vs/sqrt((R1+R2)^(2)+Xeq^(2));//starting current in A
+Xeqnew=(f/fst)*Xeq;//inductive reactance at 50Hz
+I2stnew=Vs/sqrt((R1+R2)^(2)+Xeqnew^(2));//starting current at 50Hz in A
+mprintf("\nThe starting current at 50Hz is %f A",I2stnew)