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how to solve this problem in matlab better if you use a loop EXAMPLE 6.9 Design

ID: 2073213 • Letter: H

Question






how to solve this problem in matlab better if you use a loop

EXAMPLE 6.9 Design a starter for the DC shunt moor of Example 6.7 using external resistance to be connected in senes with the armature as shown in Fig. 6.26. This resistance is to be cut out in steps so that the armature current does not exceed 200% of full-load armature current. As the motor speeds ap. the armature current will drop. As soon as the armature cument falls to its full-load value. sufficient resistance is to be cut out so that the current eetums to the 200 level. This process is repeated until the full starting resistance is shorted out. The field winding is to be connected directly across the DC supply FlGVEE 6.26 DC moeor starter of Example 69.

Explanation / Answer

Matlab Code:

Vt=220;
Eb=0;
Iar=48;
Ra=0.2;
Ias=2*Iar;
n=1;
Eb(n)=0;
Re(n)=((Vt-Eb(n))/Ias)-Ra;
while(Re(n)>0)%enters into loop only when Re is greater than zero
Eb(n+1)=Vt-(Iar*(Re(n)+Ra));
n=n+1;
Re(n)=((Vt-Eb(n))/Ias)-Ra;
end
disp(Re);
disp(Eb);
number_of_stages = n-1;
Rs1 = Re(1)-Re(2);
Rs2 = Re(2)-Re(3);
Rs3 = Re(3)-Re(4);
Rs4 = Re(4);
disp(Rs1);
disp(Rs2);
disp(Rs3);
disp(Rs4);

Command window output:

2.0917 0.9458 0.3729 0.0865 -0.0568

0 110.0000 165.0000 192.5000 206.2500

1.1458

0.5729

0.2865

0.0865