#Variable declaration
I_1 = 10.0 #Current(A)
T_1 = 54.0 #Torque(N-m)
I_2 = 20.0 #Current(A)
T_2 = 142.0 #Torque(N-m)
I_3 = 30.0 #Current(A)
T_3 = 250.0 #Torque(N-m)
I_4 = 40.0 #Current(A)
T_4 = 365.0 #Torque(N-m)
I_5 = 50.0 #Current(A)
T_5 = 480.0 #Torque(N-m)
I_6 = 60.0 #Current(A)
T_6 = 620.0 #Torque(N-m)
I_7 = 70.0 #Current(A)
T_7 = 810.0 #Torque(N-m)
E = 500.0 #Operating voltage(V)
R_a = 0.6 #Armature resistance(ohm)
#Calculation
N_1 = 9.55*(E-I_1*R_a)*I_1/T_1 #Speed(rpm)
N_2 = 9.55*(E-I_2*R_a)*I_2/T_2 #Speed(rpm)
N_3 = 9.55*(E-I_3*R_a)*I_3/T_3 #Speed(rpm)
N_4 = 9.55*(E-I_4*R_a)*I_4/T_4 #Speed(rpm)
N_5 = 9.55*(E-I_5*R_a)*I_5/T_5 #Speed(rpm)
N_6 = 9.55*(E-I_6*R_a)*I_6/T_6 #Speed(rpm)
N_7 = 9.55*(E-I_7*R_a)*I_7/T_7 #Speed(rpm)
#Result
print('Speed-current of the motor')
print('_______________________________________')
print(' Current(A) : Speed(rpm) ')
print('_______________________________________')
print(' %.f : %.f ' %(I_1,N_1))
print(' %.f : %.f ' %(I_2,N_2))
print(' %.f : %.f ' %(I_3,N_3))
print(' %.f : %.f ' %(I_4,N_4))
print(' %.f : %.f ' %(I_5,N_5))
print(' %.f : %.f ' %(I_6,N_6))
print(' %.f : %.f ' %(I_7,N_7))
print('_______________________________________')
print('\nNOTE: ERROR: Calculation mistakes in the textbook solution')
#Variable declaration
N_1 = 500.0 #Speed(rpm)
I_1 = 50.0 #Current(A)
E_1 = 220.0 #Armature voltage(V)
I_2 = 100.0 #Current(A)
E_2 = 350.0 #Armature voltage(V)
I_3 = 150.0 #Current(A)
E_3 = 440.0 #Armature voltage(V)
I_4 = 200.0 #Current(A)
E_4 = 500.0 #Armature voltage(V)
I_5 = 250.0 #Current(A)
E_5 = 540.0 #Armature voltage(V)
I_6 = 300.0 #Current(A)
E_6 = 570.0 #Armature voltage(V)
R_wb = 0.08 #Armature and brush resistance(ohm)
R_f = 0.05 #Resistance of series field(ohm)
V = 600.0 #Operating voltage(V)
#Calculation
R_a = R_wb+R_f #Armature resistance(ohm)
N_11 = N_1/E_1*(V-I_1*R_a) #Speed(rpm)
T_1 = 9.55*E_1*I_1/N_1 #Torque(N-m)
N_2 = N_1/E_2*(V-I_2*R_a) #Speed(rpm)
T_2 = 9.55*E_2*I_2/N_1 #Torque(N-m)
N_3 = N_1/E_3*(V-I_3*R_a) #Speed(rpm)
T_3 = 9.55*E_3*I_3/N_1 #Torque(N-m)
N_4 = N_1/E_4*(V-I_4*R_a) #Speed(rpm)
T_4 = 9.55*E_4*I_4/N_1 #Torque(N-m)
N_5 = N_1/E_5*(V-I_5*R_a) #Speed(rpm)
T_5 = 9.55*E_5*I_5/N_1 #Torque(N-m)
N_6 = N_1/E_6*(V-I_6*R_a) #Speed(rpm)
T_6 = 9.55*E_6*I_6/N_1 #Torque(N-m)
#Result
print('Speed-torque curve for motor')
print('_______________________________________')
print(' Speed(rpm) : Torque(N-m) ')
print('_______________________________________')
print(' %.f : %.f ' %(N_11,T_1))
print(' %.f : %.f ' %(N_2,T_2))
print(' %.f : %.f ' %(N_3,T_3))
print(' %.f : %.f ' %(N_4,T_4))
print(' %.f : %.f ' %(N_5,T_5))
print(' %.f : %.f ' %(N_6,T_6))
print('_______________________________________')
print('\nNOTE: ERROR: Calculation mistakes in the textbook solution')
#Variable declaration
V = 650.0 #Voltage supply(V)
r_A = 45.0 #Radius of driving wheel(cm)
r_B = 43.0 #Radius of driving wheel(cm)
N_A = 400.0 #Speed(rpm)
drop = 10.0 #Voltage drop(%)
#Calculation
rho = r_B/r_A
IR = drop*V/100 #Voltage drop(V)
V_A = (rho*(V-IR)+IR)/(1+rho) #Voltage(V)
V_B = V-V_A #Voltage(V)
N_A_A = N_A*(V_A-IR)/(V-IR) #N'_A(rpm)
N_B_B = N_A_A*r_A/r_B #N'_B(rpm)
#Result
print('Speed of first motor when connected in series, N_A = %.f rpm' %N_A_A)
print('Speed of second motor when connected in series, N_B = %.f rpm' %N_B_B)
print('\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here')
#Variable declaration
F_t = 33800.0 #Tractive effort(N)
V = 48.3 #Velocity(kmph)
T = 53400.0 #Tractive effort(N)
#Calculation
HP = F_t*V*1000/(60*60*746) #HP on level track(hp)
HP_i = HP*(T/F_t)**0.5 #hp delivered by locomotive for dc series motor(hp)
HP_ii = HP*T/F_t #hp delivered by locomotive for induction motor(hp)
#Result
print('hp delivered by the locomotive when dc series motor is used = %.f HP' %HP_i)
print('hp delivered by the locomotive when induction motor is used = %.f HP' %HP_ii)
#Variable declaration
I_1 = 100.0 #Current(A)
N_1 = 71.0 #Speed(kmph)
F_t1 = 2225.0 #Tractive effort(N)
I_2 = 150.0 #Current(A)
N_2 = 57.0 #Speed(kmph)
F_t2 = 6675.0 #Tractive effort(N)
I_3 = 200.0 #Current(A)
N_3 = 50.0 #Speed(kmph)
F_t3 = 11600.0 #Tractive effort(N)
I_4 = 250.0 #Current(A)
N_4 = 45.0 #Speed(kmph)
F_t4 = 17350.0 #Tractive effort(N)
I_5 = 300.0 #Current(A)
N_5 = 42.0 #Speed(kmph)
F_t5 = 23200.0 #Tractive effort(N)
D_A = 101.6 #Size of wheels(cm)
ratio_gear = 72.0/23 #Gear ratio
D_B = 106.7 #Size of wheels(cm)
ratio_gear_new = 75.0/20 #Gear ratio
#Calculation
N_B = ratio_gear*D_B/(ratio_gear_new*D_A) #Speed in terms of V(kmph)
F_tB = D_A*ratio_gear_new/(ratio_gear*D_B) #Tractive effort in terms of F_tA(N)
N_B1 = N_B*N_1 #Speed(kmph)
F_tB1 = F_tB*F_t1 #Tractive effort(N)
N_B2 = N_B*N_2 #Speed(kmph)
F_tB2 = F_tB*F_t2 #Tractive effort(N)
N_B3 = N_B*N_3 #Speed(kmph)
F_tB3 = F_tB*F_t3 #Tractive effort(N)
N_B4 = N_B*N_4 #Speed(kmph)
F_tB4 = F_tB*F_t4 #Tractive effort(N)
N_B5 = N_B*N_5 #Speed(kmph)
F_tB5 = F_tB*F_t5 #Tractive effort(N)
#Result
print('New characteristics of motor')
print('_______________________________________')
print(' Current(A) : Speed(kmph) : F_t(N)')
print('_______________________________________')
print(' %.f : %.1f : %.f ' %(I_1,N_B1,F_tB1))
print(' %.f : %.1f : %.f ' %(I_2,N_B2,F_tB2))
print(' %.f : %.1f : %.f ' %(I_3,N_B3,F_tB3))
print(' %.f : %.1f : %.f ' %(I_4,N_B4,F_tB4))
print(' %.f : %.1f : %.f ' %(I_5,N_B5,F_tB5))
print('_______________________________________')
print('\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here')