Chapter 8: Thyristors

Example 8.3,Page 397

In [1]:
#finding inductance,load impedence

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=220.0;#line voltage
f=50.0;#hertz
R=80.0;#load resistance
K=50.0;#di/dt

#calculation
L=V*2**.5/K;
Z=2*pi*f*L;

#result
print "inductance is",round(L,2),"microH"
print "load impedence at angle 90 degree is",round(Z*1e-6,5), "ohm"

inductance is 6.22 microH
load impedence at angle 90 degree is 0.00195 ohm

Example 8.4,Page 400

In [3]:
#finding capacitor,current

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=220.0;#line voltage
f=50.0;#hertz
R=80.0;#load resistance
K=75.0;#dv/dt
Vd=400.0;#DRM voltage


#calculation
C=Vd/R/K;
C1=.1;
Z=1/(2*pi*f*C1);
Iload=V/1000/(-Z*cos(180*pi/180)+R*round(cos(90*pi/180)));
Vload=Iload/1000*R;
P=Vload*Iload;

#result
print "minimum value of capacitor is",round(C,3), "micfoF"
print('\nchoose C=.1 micoF')
print "capacitor impedence at angle -90degree is",round(Z*1000,2), "ohm"
print "Load current in mA at an angle 90 degrees is",round(Iload,2)
print "Potential drop in V at an angle 90 degrees is",round(Vload,2)
print "Power dissipated is",int(P), "mW"

minimum value of capacitor is 0.067 micfoF

choose C=.1 micoF
capacitor impedence at angle -90degree is 31.83 ohm
Load current in mA at an angle 90 degrees is 6.91
Potential drop in V at an angle 90 degrees is 0.55
Power dissipated is 3 mW

Example 8.5,Page 402

In [4]:
#finding snubbing resistance

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=220;#line voltage
f=50;#hertz
R=80;#load resistance
I=46;#TSM current

#calculation
Rs=V*2**.5/(I-V*2**.5/R);

#result
print "snubbing resistnce is",round(Rs,2), "ohm"

snubbing resistnce is 7.39 ohm

Example 8.6,Page 414

In [5]:
#finding voltage , power and cycles

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
R=10.0;#load
V=120.0;#rms voltage
f=60.0;#hertz
T=83.3;#ms
t1=15;#ms
t2=55;#ms

#calculation
Tl=1/f;
Th=Tl/2;
C=round(T/Th/100)*100;
D1=.2;
V1=round(V*D1**.5);
P1=V1**2/R;
D2=.7;
V2=round(V*D2**.5);
P2=V2**2/R;

#result
print "line period is",round(Tl*1000,2), "ms"
print "half-cycle time is",round(Th*1000,3), "ms"
print "no. of cycles is",C/1000
print "voltage for t1 is",round(V1,3), "V"
print "power for t1 is",round(P1,3), "W"
print "voltage for t2 is",round(V2,3), "V"
print "voltage for t2 is",round(P2,3), "W"

line period is 16.67 ms
half-cycle time is 8.333 ms
no. of cycles is 10.0
voltage for t1 is 54.0 V
power for t1 is 291.6 W
voltage for t2 is 100.0 V
voltage for t2 is 1000.0 W

Example 8.8,Page 427

In [7]:
#finding dc volatge,average voltage,rms voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=120.0;#line voltage
A=60.0;#degree
D=0.35;

#calculation
Va=D*V;
Vd=V*2**.5*(cos(A*pi/180)+1)/2/pi;
Vr=.9*V;
Vrms=V*(2**.5)*(.5*(pi-1.047)+.25*sin(2*A*pi/180))**.5/pi**.5;

#result
print "average voltage is",round(Va,3), "V"
print "dc voltage is",round(Vd), "V"
print('\nthe markers indicae Vp=163V Vave=41')
print "full-wave rms voltage is",round(Vr), "V"
print "rms voltage is",round(Vrms), "V"
print('\nthe markers indicate Vp=169V ;Vave=106V')

average voltage is 42.0 V
dc voltage is 41.0 V

the markers indicae Vp=163V Vave=41
full-wave rms voltage is 108.0 V
rms voltage is 108.0 V

the markers indicate Vp=169V ;Vave=106V

Example 8.9,Page 430

In [8]:
#finding rms voltage and double checked rms voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=220.0;#line voltage
P=1.3;#kW
R=15.0;#ohm

#calculation
Vr=round((P*1000*R)**.5);
D=Vr/V;
Vr=V*2**.5*(.5*(pi-1.710)+sin(196*pi/180)/4)**.5/pi**.5;

#result
print "rms voltage is",round(Vr,2), "V"
print "double checked value of rms voltage is",round(Vr,2), "V"

rms voltage is 141.18 V
double checked value of rms voltage is 141.18 V