User:Mdf haque

Q: Why does rotor rotate of an induction motor?

When 3-phase supply is connected to the 3-phase induction motor then, three windings of 3-phase induction motor produce a rotational field. The magnitude of this field (flux) is constant. These fluxes pass through the air gap and also pass in the rotor bar. As a result the conductor (rotor bar) of rotor cuts the lines of fluxes. We know if a conductor cuts the lines of flux then a voltage is induce in this conductor (from Faraday’s electro magnetic law). So a voltage is induced in the rotor conductor. The frequency of rotor voltage would be same to the supply frequency. And the rotor voltage is directly proportional to the relative velocity between revolving field & rotor. Forasmuch as rotor conductor is a close loop. So the current flow in this conductor. And it’s given by Lenz’s law. Now we can say from Lenz’s law, the current of rotor conductor allays try to oppose the relative velocity between revolving field & rotor. As a result the rotor starts to rotate (bcz a torque is generated) in the same direction of flux to reduce relative velocity between revolving field & rotor.

Q: Write a matlab program of Ascending & Descending row matrix.

Program: clc; clear al; a=input('Enter the size of matrix'); disp('Enter the element'); for i =1:a;

   b(i)=input(' ');

end for i=1:a

   for j=1:a-1;
   if (b(j)<b(j+1));
       m(j)=b(j);
       b(j)=b(j+1);
       b(j+1)=m(j);
    end
   end

end

fprintf('Descending order:'); b fprintf('Ascending order:\n'); for i=1:a

   for j=1:a-1
       if (b(j)>b(j+1))
           m(j)=b(j);
           b(j)=b(j+1);
           b(j+1)=m(j);
       end
   end

end b