In [1]:

    

import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

plt.style.use('ggplot')


    

In [16]:

    

# Concactor data

# number of turns
n = 2

# current [A]
I = 1000

# air gap [m]
delta = 5/1000

# length of the core [m]
lav = (200+2*150)/1000

# length of a moveable part of the core [m]
lz = 200/1000

# core cross-section [m2]
S = 50/1000 * 50/1000

# moveable part cross-section
Sz = S

# air gap cross-section
Sdelta = S

# megnetic permability of vaccum [H/m]
mi_o = 4*np.pi*1e-7

# magnetic perability of the core
mi_r = 100


    

In [17]:

    

# magnetic permeance

# core
Ac = mi_o*mi_r*S / lav

# movable part of the core
Az = mi_o*mi_r*Sz / lz

# of two air gaps
Adelta = mi_o*Sdelta / (2*delta)

print("Permeance of the core: {} [H]".format(Ac))
print("Permeance of the moveable part of the core: {} [H]".format(Az))
print("Permeance of the air gaps: {} [H]".format(Adelta))


    

    




Permeance of the core: 6.283185307179588e-07 [H]
Permeance of the moveable part of the core: 1.5707963267948969e-06 [H]
Permeance of the air gaps: 3.141592653589793e-07 [H]

In [18]:

    

# inductance 
L = n**2 * (Ac + Az + Adelta)
L


    

    
Out[18]:





1.0053096491487338e-05

In [19]:

    

# force acting on the moveable part of the core
F = 1/4 * (I*n)**2 * mi_o*Sdelta/(delta**2)
F


    

    
Out[19]:





125.66370614359172

In [20]:

    

# range of gap change
x = np.linspace(0.5/1000, 5/1000, 30)
Fe = 1/4 * (I*n)**2 * mi_o*Sdelta/(x**2)

plt.plot(x*1000, Fe/1000)
plt.xlabel('Gap [mm]')
plt.ylabel('Force [kN]');


    

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