import math
from math import sqrt
V=415.0 #AC input voltage
Vf=2.53 #voltage safety factor
PIV=2*sqrt(2)*V*Vf #peak inverse voltage of the device
PIV=round(PIV,2)
print 'peak inverse voltage of the device=PIV=',PIV,'Volts'
import math
from math import sqrt
V=415.0 #AC input voltage in volts
PIV=1350.0 #peak inverse voltage of the device in volts
Vf=PIV/(sqrt(2)*V) #voltage safety factor of the device
Vf=round(Vf,2)
print 'voltage safety factor of the device=Vf=',Vf
import math
P=100.0 #input power in KVA
Xt=0.04 #limiting ac reactance value
Fov=2.0 #current ovarload factor
Pc=Xt*P*Fov #choke power of the converter in KVA
print 'choke power of the converter=Pc=',Pc,'KVA'
import math
from math import sqrt
Ls=0.1 #stray inductance in the circui t in milli Henry
L=2*Ls #inductance required for the snubber ckt for protection in mH
Im=250.0 #mean value of current in amp
C=2.5*Im #capacitance required for the snubber ckt in nano Farads
print 'capacitance in snubber circuit=C=',C,'nanofarads'
R=2*100*sqrt(L/C) #resistance in snubber circ uit in Kilo Ohms
R=round(R,2)
print 'Resistance in snubber circuit=R=',R,'Kilo Ohms'
Pdif=1*30.0 #permissible dv/dt of the circuit
print 'Permissible dv/dt of the circuit=',Pdif,'MV/s'
import math
V=240.0 #dc input voltage in volts
Vh=25.0 #each selenium plate handling voltage in volts
N=V/Vh #number of plates in series in the circuit
print 'number of plates in series in the circuit=N=',N
print 'So,we will use 10 plates in the circuit'
import math
V=230.0 #ac input voltage in volts
Vh=30.0 #each selenium plate handling voltage in volts
N=(V/Vh)+1 #number of plates in series in each direction in the ckt
N=round(N,0)
print 'number of plates in series in each direction =N=',N
Nt=2*N #total number of plates in series in the circuit
Nt=round(Nt,0)
print 'total number of plates in series in both directions=Nt=',Nt
import math
V=415.0 #ac input voltage in volts
Vdc=440.0 #supplied voltage to dc motor in volts
Vh=30.0 #each selenium plate handling voltage in volts
N=Vdc/Vh #number of plates in series in each direction in the ckt
N=15.0
print 'number of plates in each branch=N=',N
Nt=3*N #total number of plates in series in the circuit
Nt=round(Nt,0)
print 'total number of plates=Nt=',Nt
Ipa=136.0 #peak armature current in amperes
T=30.0 #time constant in milliseconds
R=0.175 #Armature resistance in Ohms
L=T*R #Armature circuit Inductance in milliHenry
L=round(L,2)
print 'Armature circuit inductance=L=',L,'mH'
Es=0.5*L*Ipa**2*10**-3 #Energy stored in armature circuit in wattsec
Es=round(Es,2)
print 'Energy stored in armature circuit=Es=',Es,'wattsec'
Ed=Es/N #Energy dissipated per plate in wattsec
Ed=round(Ed,2)
print 'Energy dissipated per plate=Ed=',Ed,'wattsec'