Excercises Electric Machinery Fundamentals

Chapter 6 Problem 6-19



In [1]:

    
%pylab inline









    



Populating the interactive namespace from numpy and matplotlib

A dc test is performed on a 460-V $\Delta$-connected 100-hp induction motor. If $V_{DC} = 21\,V$ and $I_{DC} = 72\,A$,



In [2]:

    
Vdc = 21.0 # [V]
Idc = 72.0 # [A]

If this motor’s armature is connected in delta, then there will be two phases in parallel with one phase between the lines tested.

Therefore, the stator resistance $R_1$ will be:

$$\frac{V_{DC}}{I_{DC}} = \frac{R_1(R_1 + R_2)}{R_1 + (R_1 + R_2)} = \frac{2}{3}R_1$$$$R_1 = \frac{3}{2}\frac{V_{DC}}{I_{DC}}$$



In [3]:

    
R1 = 3/2 * Vdc/Idc
print('''
R1 = {:.3f} Ω
============'''.format(R1))









    



R1 = 0.438 Ω
============