Electric Machinery Fundamentals 5th edition

Chapter 1 (Code examples)

Example 1-1:

Import the PyLab namespace (provides set of useful commands and constants like Pi)



In [1]:

    
%pylab inline









    



Populating the interactive namespace from numpy and matplotlib

Define all the parameters:



In [2]:

    
l1 = 0.45                 # Length of region 1
l2 = 1.3                  # Length of region 2
a1 = 0.01                 # Area of region 1
a2 = 0.015                # Area of region 2
ur = 2500                 # Relative permeability
u0 = 4*pi*1e-7            # Permeability of free space
n = 200                   # Number of turns on core
i = 1                     # Current in amps

Calculate the first reluctance:



In [3]:

    
r1 = l1 / (ur * u0 * a1)

Calculate the second reluctance:



In [4]:

    
r2 = l2 / (ur * u0 * a2)

Calculate the total reluctance



In [5]:

    
rtot = r1 + r2

Calculate the mmf



In [6]:

    
mmf = n * i

Finally, get the flux in the core:



In [7]:

    
flux = mmf / rtot

Display the result:



In [8]:

    
print('r1 = {}'.format(r1))
print('r2 = {}'.format(r2))
print('Flux = {}'.format(flux))









    



r1 = 14323.944878270579
r2 = 27586.856802595194
Flux = 0.004772039473807281

(I'm using the new style PyFormat in order to make the output above a bit nicer.)