diff options
Diffstat (limited to '1445/CH8/EX8.8')
| -rw-r--r-- | 1445/CH8/EX8.8/Ex8_8.sce | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/1445/CH8/EX8.8/Ex8_8.sce b/1445/CH8/EX8.8/Ex8_8.sce new file mode 100644 index 000000000..0eb7a9dd1 --- /dev/null +++ b/1445/CH8/EX8.8/Ex8_8.sce @@ -0,0 +1,50 @@ +//CHAPTER 8- DIRECT CURRENT MACHINES +//Example 8 + +disp("CHAPTER 8"); +disp("EXAMPLE 8"); + +//250 V DC shunt machine +//VARIABLE INITIALIZATION +v_t=250; //in Volts +r_a=0.1; //armature resistance in Ohms +r_f=125; //field resistance in Ohms +p_o=20*1000; //output power in Watts +N_g=1000; //speed as generator in rpm + +//SOLUTION + +//machine as a generator +I_l=p_o/v_t; //load current +I_f=v_t/r_f; //field current, I_f is same as I_sh +I_ag=I_l+I_f; //Output current as generator +E_a=v_t+(I_ag*r_a); //induced emf = E_a = E_g + +//machine as a motor +I_l=p_o/v_t; //full load current +I_f=v_t/r_f; +I_am=I_l-I_f; //output current as motor +E_b=v_t-(I_am*r_a); //back emf = E_b = E_m + +//solution (a) +N_m=(N_g*E_b)/E_a; //Speed of motor in RPM +N_m=round(N_m); //to round off the value of N_m +disp(sprintf("(a) The speed of the same machine as a motor is %d rpm",N_m)); + +//solution (b) +//internal power developed as generator +//(i) +//total power developed in the armature +//=Eg.Iag +p_g=(E_a*I_ag)/1000; //to express the answer in kW divide by 1000 +disp(sprintf("(b) (i) The internal power developed as generator is %.1f kW",p_g)); + +//(ii) +//internal power developed as motor +// is total power developed in armature +//=Em.Iam +p_m=(E_b*I_am)/1000; +disp(sprintf("(b) (ii) The internal power developed as motor is %.1f kW",p_m)); + +//END + |