import math
# Variables
N = 200.; #turns
c = 600.; #mm(circumference)
A = 500.; #m**2(Cross section area)
I = 4.; #A(Current through coil)
# Calculations and Results
H = I*N/(c*10**-3); #A/m(Magnetic field strength)
print "(a) Magnetic field strength(A/m) : %.2f"%H
mu0 = 4*math.pi*10**-7; #constant
FD = mu0*H*10**6; #micro T(Flux density)
print "(b) Flux density(micro T) : %.2f"%FD
Ft = FD*A*10**-6; #micro Wb(Total flux)
print "(c) Total flux(micro Wb) : %.2f"%Ft
#Answer in the book is wrong.
import math
# Variables
fi = 0.015; #Wb(flux)
ag = 2.5; #mm(airgap)
Ae = 200; #cm**2(Effective area)
# Calculations
FD = fi/(Ae*10**-4); #T(Flux density)
mu0 = 4*math.pi*10**-7; #constant
H = FD/mu0; #A/m(Magnetic field strength)
mmf = H*ag*10**-3; #A(magnetomotive force required)
# Results
print "Magnetomotive force required(A) : %.2f"%mmf
#Answer in the book is not accurate.
import math
# Variables
A = 500.; #mm**2(Cross sectional area)
c = 400.; #mm(circumference)
N = 200.; #turns
fi = 800.; #micro Wb(flux)
# Calculations and Results
B = fi*10**-6/(A*10**-6); #T(Flux density)
mu0 = 4*math.pi*10**-7; #constant
mur = 380.; #relative permeability
S = (c/1000)/(mur*mu0*A*10**-6); #A/Wb(Relucmath.tance)
print "(a) Relucmath.tance of the ring(A/Wb) :%.2e"%S
mmf = fi*10**-6*S; #A
Im = mmf/N; #A(Magnetizing current)
print "(b) Required magnetizing current(A) :%.2f"%Im
import math
# Variables
la = 80.; #mm
Aa = 50.; #mm**2(Cross sectional area)
lb = 60.; #mm
Ab = 90.; #mm**2(Cross sectional area)
lc = 0.5; #mm(airgap)
Ac = 150.; #mm**2(Cross sectional area)
N = 4000.; #turns
Bc = 0.30; #T(Flux density in airgap)
# Calculations
mu0 = 4*math.pi*10**-7; #constant
mur = 1300; #relative permeability
fi = Bc*Ac*10**-6; #Wb(flux)
Fa = fi*la*10**-3/(mu0*mur*Aa*10**-6); #At
Fb = fi*lb*10**-3/(mu0*mur*Ab*10**-6); #At
Fc = fi*lc*10**-3/(mu0*1*Ac*10**-6); #At
F = Fa+Fb+Fc; #At
I = F/N*1000; #mA
# Results
print "Coil current(mA) : %.2f"%I
# Variables
L = 0.5; #H
deltaI = 2-5; #A
deltaT = 0.05; #sec
# Calculations
dIBYdT = deltaI/deltaT; #A/s
emf = L*dIBYdT; #V
# Results
print "emf induced(V) : %.2f"%emf
# Variables
N = 300; #turns
L = 10.; #mH
I = 5; #A
# Calculations and Results
fi = L*10**-3/N*I*10**6; #micro Wb
print "(a) Flux produced(micro Wb) : %.f"%fi
#on reverse the current
delta_fi = 2*fi; #micro Wb
#(as it goes to zero and increase to same value in reverse direction)
deltaT = 8*10**-3; #seconds
dfiBYdT = delta_fi*10**-6/deltaT; #Wb/s
emf = N*dfiBYdT; #V(Average emf induced)
print "(b) Average emf induced(V) : %.2f"%emf
# Variables
c = 400.; #mm(circumference)
A = 500.; #mm**2(Cross sectional area)
N = 200.; #turns
# Calculations and Results
#Part (a)
I = 2; #A
H = N*I/(c*10**-3); #A/m
B = 1.13; #T(Corresponding Flux density)
fi = B*A*10**-6; #Wb(total flux)
L = N*fi/I*1000; #mH
print "(a) Inductance of coil(mH) : %.2f"%L
#Part (a)
I = 10; #A
H = N*I/(c*10**-3); #A/m
B = 1.63; #T(Corresponding Flux density)
fi = B*A*10**-6; #Wb(total flux)
L = N*fi/I*1000; #mH
print "(b) Inductance of coil(mH) : %.2f"%L
import math
# Variables
c = 400; #mm(circumference)
A = 500; #mm**2(Cross sectional area)
N = 200; #turns
# Calculations
mu0 = 4*math.pi*10**-7; #constant
L = mu0*A*10**-6*(N**2)/(c*10**-3)*10**6; #micro H
# Results
print "Inductance(micro H) : %.2f"%L
import math
# Variables
A = 800; #mm**2(Cross sectional area)
r = 170; #mm(radius)
N1 = 500; #turns
N2 = 700; #turns
mur = 1200; #relative permeability
# Calculations and Results
mu0 = 4*math.pi*10**-7; #constant
S = 2*math.pi*r*10**-3/(mu0*mur*A*10**-6); #H
L1 = N1**2/S; #H
print "Self Inductance of coil 1(H) : %.2f"%L1
L2 = N2**2/S; #H
print "Self Inductance of coil 2(H) : %.2f"%L2
k = 1; #constant
M = k*math.sqrt(L1*L2); #H
print "Mutual Inductance(H) : %.2f"%M