30-03-2012, 03:37 PM
DC MECHINE
DC_MACHINE.ppt (Size: 2.34 MB / Downloads: 63)
SEPARATELY ECXITED DC GENERATOR
Analysis of eqn(3) indicates that the angular velocity of the separately excited motor can be regulated by changing the applied voltages to the armature and field windings.
The flux is a function of the field current in the stator winding, and higher angular velocity can be achieved by field weakening by reducing the stator current [eqn(3)]
However, there exists a mechanical limit imposed on the maximum angular velocity. The maximum allowed (rated) armature current is specified as well, one concludes that the electromagnetic torque is bounded.
SEPARATELY ECXITED DC MOTOR
%transient dynamics of a separately excited dc motor
clc
t0=0; tfinal=0.4; tol=1e-7; trace=1e-7; y0=[0 0 0]';
[t,y]=ode45('CHP5_1mdno',t0,tfinal,y0,tol,trace);
subplot(2,2,1); plot(t,y(:,1),'r-');
xlabel('Time (seconds)'); title('Armature Current ia, [A]');
subplot(2,2,2); plot(t,y(:,2),'g-.');
xlabel('Time (seconds)'); title('Field Current if, [A]');
subplot(2,2,3); plot(t,y(:,3),'b-');
xlabel('Time (seconds)'); title('Angular Velocity wr, [rad/s]');
subplot(2,2,4);plot(t,y(:,1),'r-',t,y(:,2),'g-.',t,y(:,3),'b-')
xlabel('Time (seconds)'); title('LAB 1');