Chapter 3 : Power Parameter Calculations

Example 3.1,Page 109

In [1]:
#finding ramp current and current at 5 micro sec

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Ip=3.0;
f=150000.0;
t=5.0e-6;

#calculation
T=1/f;
It=Ip/T;
I5=It*t;

#result
print "ramp current is",round(It/1000,3), "kAt/s"
print "current at 5 micro sec is",round(I5,3), "A"

ramp current is 450.0 kAt/s
current at 5 micro sec is 2.25 A

Example 3.2,Page 110

In [2]:
#finding current at different time

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Ip=2.0;
f=500000.0;
Ir=.3;
Cd=.4#duty cycle
t1=4.0e-7;
t2=1.0e-6;
I1=0;

#calculation
T=1/f;
Im=Ip-Ir;
I4=(Ip-Im)*t1/(Cd*T)+Im;
It=(Ip-Im)*t/(Cd*T)+Im;
It1=0

#resilt
print "current in time 0<=t<800ns is",round(It,3),"A"
print "current in time 800ns<=t<2 microsec is",round(It1,2), "A"
print "current in time 400ns is",round(I4,2), "A"
print "current in time 1 microsec is",round(I1,2), "A"

current in time 0<=t<800ns is 3.575 A
current in time 800ns<=t<2 microsec is 0.0 A
current in time 400ns is 1.85 A
current in time 1 microsec is 0.0 A

Example 3.3,Page 115

In [3]:
#finding average voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Vr=120;

#calculation
V=(Vr*2**.5)/pi;

#result
print "average voltage is",round(V,2), "V"

average voltage is 54.02 V

Example 3.4,Page 119

In [5]:
#finding average current

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
f=100000.0;
Cd=.35#duty cycle
Ip=3.0;
Ir=.4;

#calculation
Im=Ip-Ir;
T=1/f;
I=Cd*((Ip-Im)/2+Im)

#result
print "average current is",round(I,2), "A"

average current is 0.98 A

Example 3.5,Page 124

In [6]:
#finding rms voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Vp=15.0;
Cd=.35;
f=100000.0;

#calculation
V=Vp*Cd**.5;

#result
print "rms voltage is",round(V,2), "V"

rms voltage is 8.87 V

Example 3.6,Page 127

In [7]:
#finding rms current

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Ip=3.0;
f=100000.0;

#calculation
I=Ip/3**.5;

#result
print "rms current is",round(I,2), "A"

rms current is 1.73 A

Example 3.7,Page 133

In [8]:
#finding rms voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Vp=170.0;
f=60.0;

#calculation
Vr=Vp/2;

#result
print "rms voltage is",round(Vr,2), "V"

rms voltage is 85.0 V

Example 3.8,Page 140

In [9]:
#finding current and power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
M=1000.0;
H=40.0;
T=30.0;
E1=.9;
E2=.5;
V=220.0;
P1=5.0;

#calculation
W=M*H;
P=(W)/(T*550);
Pe=P1/E1;
I=(Pe*746)/V;

#result
print "power required is",round(P,2), "hp"
print('Pick a 5HP motor')
print "current required is",round(I,2), "amp"

power required is 2.42 hp
Pick a 5HP motor
current required is 18.84 amp

Example 3.9,Page 145

In [10]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Vin=1.0;
Ri=1100.0;
Rf=10000.0;
Rl=8.0;
Vs=18.0;

#calculation
Ir=Vin/Ri;
Vl=Ir*(Ri+Rf);
Ip=Vl/Rl;
Pl=(Vl*Ip)/2;
Ps=(Vs*Ip)/pi;

#result
print "power delivered to the load is",round(Pl,2),"Watt"
print "power provided by each supply is",round(Ps,2), "Watt"

power delivered to the load is 6.36 Watt
power provided by each supply is 7.23 Watt

Example 3.10,Page 149

In [11]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=170.0;
R=51.0;

#calculation
I=V/R;
P=(V*I)/4;

#result
print "power delivered is",round(P,2), "Watt"

power delivered is 141.67 Watt

Example 3.11,Page 151

In [12]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=7.2;
Rq=.2;
Rl=4;
D=.6;

#calculation
Ip=V/(Rq+Rl);
Vl=Ip*Rl;
P=D*Vl*Ip;
Vq=Ip*Rq;
Pq=D*Vq*Ip;

#result
print "power dissipated is",round(P,2), "watt"
print "power dissipated when transistor resistance is 0.2 hm is",round(Pq,2), "watt"

power dissipated is 7.05 watt
power dissipated when transistor resistance is 0.2 hm is 0.35 watt