Page 288 - Solutions Manual to accompany Electric Machinery Fundamentals
P. 288

(c) Input power
                 (d)   P AG
                 (e)   P conv
                 (f)   P out
                 (g)  
                        ind
                 (h)   load
                 (i)  Efficiency  
                 SOLUTION  The equivalent circuit of the motor is shown below

                      I 1
                                R 1      jX 1        j0.5X 2
                                        {                                       R
                         +     1.30 ?   j2.01 ?      j2.01 ?




                                    0.5Z F         j0.5X M                    5 . 0  s 2   Forward
                                                    j105 ?





                                                                                              {
                   V = 220?0° V                        jX 2
                                                     j105 ? {  j2.01 ?






                                                     j0.5X M                  5 . 0  R 2     Reverse
                                   0.5Z B                                       2    s         {


                         -



                 The impedances Z  and  Z  are:
                                          B
                                  F
                              R s   jX   jX  
                                 /
                         Z     2       2    M
                          F
                               R 2  / s   jX   2  jX M
                 The slip s   0.05 , so  R 2   / s   1.73   / 0.05 20.6  
                                    j   20.6     105  2.01 j
                         Z   F                    19.12   j 5.654
                                                                
                               20.6   j 2.01  j 105
                                   R     /2 s   2   jX    jX
                         Z     2                 M
                          B
                                2   R     /2 s   jX   2  jX M
                 The slip s   0.05 , so  R 2     / 2 s       1.73    / 2 0.05   0.887  
                                      2.01 j 105  j
                                           
                                          0.887 
                         Z   B                     0.854   j 1.979 
                              0.887   j 2.01  j 105
                 (a)  The input stator current is
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