# a
import math
efficiency = 0.9;
Pi = 200.*746./efficiency; # input power
x = 11.; # reactance of the motor
V1 = 2300./math.sqrt(3.); # voltage rating
delta = 15.*math.pi/180.; # power angle
Ef = Pi*x/(3.*V1*math.sin(delta)); # the induced excitation voltage per phase
print '%s' %("a")
print '%s %.2f' %("the induced excitation voltage per phase = ",Ef)
# b
z = complex(0,x); # impedance of the motor
ef = complex(Ef*math.cos(-delta),Ef*math.sin(-delta));
Ia = (V1 - ef)/z ; # armature current
print '%s' %("b")
print "armatur current = ",Ia
# c
theata =0.693;# math.atan(imag(Ia)/real(Ia)); # phase difference between Ia and V1
pf = math.cos(theata); # power factor
print '%s' %("c")
print '%s %.2f' %("power factor = ",pf)
if math.sin(theata)> 0 :
print '%s' %("leading")
else :
print '%s' %("lagging")