In [1]:

```
#Variable declaration
P = 10000.0 #Power rating of the shunt generator(W)
V = 230.0 #Voltage rating of the shunt generator(V)
S = 1750.0 #Speed of the shunt generator(rpm)
V_a = 245.0 #Voltage across armature(V)
I_a = 2.0 #Armature current(A)
R_f = 230.0 #Field resistance(ohm)
R_a = 0.2 #Armature resistance(ohm)
#Calculation
#Case(a)
Rotational_loss = V_a*I_a-(I_a**2*R_a) #Rotational losses at full load(W)
#Case(b)
V_t = V
I_L = P/V_t #Line current(A)
I_f = V/R_f #Field current(A)
Ia = I_f+I_L #Armature current(A)
armature_loss = Ia**2*R_a #Full-load armature loss(W)
V_f = V
field_loss = V_f*I_f #Full-load field loss(W)
#Case(c)
n = P/(P+Rotational_loss+(armature_loss+field_loss))*100 #Efficiency of the generator at rated load(%)
#Result
print('Case(a): Rotational losses at full load , Rotational losses = %.1f W' %Rotational_loss)
print('Case(b): Full-load armature circuit loss , I_a^2*R_a = %.f W' %armature_loss)
print(' Field loss , V_f*I_f = %.f W' %field_loss)
print('Case(c): Efficiency of the generator at rated load , η = %.1f percent' %n)
```

In [1]:

```
#Variable declaration
P = 10000.0 #Power rating of the shunt generator(W)
Rotational_loss = 489.2 #Rotational loss at full load(W)
armature_loss = 396.0 #Full-load armature loss(W)
field_loss = 230.0 #Full-load field loss(W)
x1 = 1.0/4 #Fraction of full-load
x2 = 1.0/2 #Fraction of full-load
x3 = 3.0/4 #Fraction of full-load
x4 = 5.0/4 #Fraction of full-load
#Calculation
n_a = (P*x1)/((P*x1)+Rotational_loss+(armature_loss*(x1**2)+field_loss))*100 #Efficiency of generator(%)
n_b = (P*x2)/((P*x2)+Rotational_loss+(armature_loss*(x2**2)+field_loss))*100 #Efficiency of generator(%)
n_c = (P*x3)/((P*x3)+Rotational_loss+(armature_loss*(x3**2)+field_loss))*100 #Efficiency of generator(%)
n_d = (P*x4)/((P*x4)+Rotational_loss+(armature_loss*(x4**2)+field_loss))*100 #Efficiency of generator(%)
#Result
print('Case(a): Efficiency of the generator at 1/4 load , η = %.1f percent' %n_a)
print('Case(b): Efficiency of the generator at 1/2 load , η = %.1f percent' %n_b)
print('Case(c): Efficiency of the generator at 3/4 load , η = %.1f percent' %n_c)
print('Case(d): Efficiency of the generator at 5/4 load , η = %.1f percent' %n_d)
```

In [1]:

```
#Variable declaration
V = 240.0 #Voltage rating of the dc shunt motor(V)
hp = 25.0 #Power rating of the dc shunt motor(hp)
S = 1800.0 #Speed of the shunt generator(rpm)
I_L = 89.0 #Full-load line current(A)
R_a = 0.05 #Armature resistance(ohm)
R_f = 120.0 #Field circuit resistance(ohm)
#Calculation
#Case(a)
V_f = V #Field voltage(V)
I_f = V_f/R_f #Field current(A)
I_a = I_L-I_f #Armature current(A)
V_a = V
E_c = V_a-I_a*R_a #Armature voltage to be applied to the motor(V)
#Case(b)
Ia = 4.2 #Armature current produced by E_c(A)
Va = E_c #Armature voltage(V)
P_r = Va*Ia #Stray power(W)
#Result
print('Case(a): Armature voltage to be applied to the motor when motor is run light at 1800 rpm during stray power test , E_c = %.2f V' %E_c)
print('Case(b): Stray power when voltage in part(a) produces an armature current of 4.2 A at 1800 rpm , P_r = %.1f W' %P_r)
```

In [1]:

```
#Variable declaration
V = 600.0 #Voltage rating of the compound motor(V)
hp = 150.0 #Power rating of the compound motor(hp)
I_L = 205.0 #Full-load rated line current(A)
S = 1500.0 #Full-load speed of the compound generator(rpm)
R_sh = 300.0 #Shunt field resistance(ohm)
R_a = 0.05 #Armature resistance(ohm)
R_s = 0.1 #Series field resistance(ohm)
V_a = 570.0 #Applied voltage(V)
I_a = 6.0 #Armature current(A)
S_o = 1800.0 #No-load speed of the compound generator(rpm)
x1 = 1.0/4 #Fraction of full-load
x2 = 1.0/2 #Fraction of full-load
x3 = 3.0/4 #Fraction of full-load
x4 = 5.0/4 #Fraction of full-load
#Calculation
#Case(a)
Rot_losses = V_a*I_a #Rotational loss(W)
S_1 = S_o-300*x1 #Speed at 1/4 load(rpm)
Rot_losses_S_1 = (S_1/S)*Rot_losses #Rotational loss at speed S_1(W)
S_2 = S_o-300*x2 #Speed at 1/2 load(rpm)
Rot_losses_S_2 = (S_2/S)*Rot_losses #Rotational loss at speed S_2(W)
S_3 = S_o-300*x3 #Speed at 3/4 load(rpm)
Rot_losses_S_3 = (S_3/S)*Rot_losses #Rotational loss at speed S_3(W)
S_4 = S_o-300*x4 #Speed at 5/4 load(rpm)
Rot_losses_S_4 = (S_4/S)*Rot_losses #Rotational loss at speed S_4(W)
#Case(b)
I_sh = V/R_sh #Full-load shunt field current(A)
Ia = I_L-I_sh #Full-load armature current(A)
FL_variable_loss = Ia**2*(R_a+R_s) #Full-load variable electric loss(W)
x1_variable_loss = FL_variable_loss*x1**2 #Variable losses at 1/4 load(W)
x2_variable_loss = FL_variable_loss*x2**2 #Variable losses at 1/2 load(W)
x3_variable_loss = FL_variable_loss*x3**2 #Variable losses at 3/4 load(W)
x4_variable_loss = FL_variable_loss*x4**2 #Variable losses at 5/4 load(W)
#Case(c)
Input_FL = V*I_L #Input at full load(W)
Input_x1 = V*I_L*x1 #Input at 1/4 load(W)
Input_x2 = V*I_L*x2 #Input at 1/2 load(W)
Input_x3 = V*I_L*x3 #Input at 3/4 load(W)
Input_x4 = V*I_L*x4 #Input at 5/4 load(W)
Field_loss = V*I_sh #Field loss for each of the conditions of load(W)
Losses_FL = Field_loss+Rot_losses+FL_variable_loss #Total losses for full load(W)
Losses_1 = Field_loss+Rot_losses_S_1+x1_variable_loss #Total losses for 1/4 load(W)
Losses_2 = Field_loss+Rot_losses_S_2+x2_variable_loss #Total losses for 1/2 load(W)
Losses_3 = Field_loss+Rot_losses_S_3+x3_variable_loss #Total losses for 3/4 load(W)
Losses_4 = Field_loss+Rot_losses_S_4+x4_variable_loss #Total losses for 5/4 load(W)
n_FL = (Input_FL-Losses_FL)/Input_FL*100 #Efficiency for full load(%)
n_1 = (Input_x1-Losses_1)/Input_x1*100 #Efficiency for 1/4 load(%)
n_2 = (Input_x2-Losses_2)/Input_x2*100 #Efficiency for 1/2 load(%)
n_3 = (Input_x3-Losses_3)/Input_x3*100 #Efficiency for 3/4 load(%)
n_4 = (Input_x4-Losses_4)/Input_x4*100 #Efficiency for 5/4 load(%)
#Result
print('Case(a): Rotational loss at full load = %.f W' %Rot_losses)
print(' Rotational loss at 1/4 times rated load = %.f W' %Rot_losses_S_1)
print(' Rotational loss at 1/2 times rated load = %.f W' %Rot_losses_S_2)
print(' Rotational loss at 3/4 times rated load = %.f W' %Rot_losses_S_3)
print(' Rotational loss at 5/4 times rated load = %.f W' %Rot_losses_S_4)
print('Case(b): Full-load variable electric losses = %.f W' %FL_variable_loss)
print(' Variable electric losses at 1/4 load = %.f W' %x1_variable_loss)
print(' Variable electric losses at 1/2 load = %.f W' %x2_variable_loss)
print(' Variable electric losses at 3/4 load = %.f W' %x3_variable_loss)
print(' Variable electric losses at 5/4 load = %.f W' %x4_variable_loss)
print('Case(c): Efficiency of motor at full load = %.1f percent' %n_FL)
print(' Efficiency of motor at 1/4 load = %.1f percent' %n_1)
print(' Efficiency of motor at 1/2 load = %.1f percent' %n_2)
print(' Efficiency of motor at 3/4 load = %.1f percent' %n_3)
print(' Efficiency of motor at 5/4 load = %.1f percent' %n_4)
print('Case(d): Table 12-2 Losses and Efficiencies for Ex. 12-4')
print('______________________________________________________________________________________________________________')
print('\t Item \t\t\t At 1/4 load \t At 1/2 load \t At 3/4 load \t At Full load \t At 5/4 load')
print('______________________________________________________________________________________________________________')
print('Input(watts)\t\t\t %d \t\t %d \t\t %d \t\t %d \t\t %d' %(Input_x1,Input_x2,Input_x3,Input_FL,Input_x4))
print('Field loss(watts)\t\t %d \t\t %d \t\t %d \t\t %d \t\t %d' %(Field_loss,Field_loss,Field_loss,Field_loss,Field_loss))
print('Rotational losses,')
print(' From part(a) (watts)\t\t %d \t\t %d \t\t %d \t\t %d \t\t %d' %(Rot_losses_S_1,Rot_losses_S_2,Rot_losses_S_3,Rot_losses,Rot_losses_S_4))
print('Variable electric losses,')
print(' From part(b) (watts)\t\t %d \t\t %d \t\t %d \t\t %d \t\t %d' %(x1_variable_loss,x2_variable_loss,x3_variable_loss,FL_variable_loss,x4_variable_loss))
print('Total of all losses(watts)\t %d \t\t %d \t\t %d \t\t %d \t\t %d' %(Losses_1,Losses_2,Losses_3,Losses_FL,Losses_4))
print('______________________________________________________________________________________________________________')
print('Efficiency η(percent)\t\t %.1f \t\t %.1f \t\t %.1f \t\t %.1f \t\t %.1f' %(n_1,n_2,n_3,n_FL,n_4))
print('______________________________________________________________________________________________________________')
print('\nNOTE: Changes in obtained answer from that of textbook is due to more precision')
```

In [1]:

```
#Variable declaration
P = 10000.0 #Power rating of the shunt generator(W)
V = 230.0 #Voltage rating of the shunt generator(V)
S = 1750.0 #Speed of the shunt generator(rpm)
V_a = 245.0 #Voltage across armature(V)
I_a = 2.0 #Armature current(A)
R_a = 0.2 #Armature resistance(ohm)
P_r = 489.2 #Shunt generator rotational losses(W)
Vf_If = 230.0 #Shunt field circuit loss(W)
I_a_rated = 44.5 #Rated armature current(A)
#Calculation
I_a = ((Vf_If+P_r)/R_a)**0.5 #Armature current at which max efficiency occurs(A)
LF = I_a/I_a_rated #Load fraction
LF_percent = LF*100 #Load fraction(%)
P_k = Vf_If+P_r
n_max = P*LF/(P*LF+(Vf_If+P_r)+P_k)*100 #Maximum efficiency(%)
LF_d = (P_k/(I_a_rated**2*R_a))**0.5 #Load fraction from fixed losses and rated variable losses
#Result
print('Case(a): Armature current at which maximum efficiency occurs , I_a = %.f A' %I_a)
print('Case(b): Load fraction , L.F = %.1f percent = %.3f*rated' %(LF_percent,LF))
print('Case(c): Maximum efiiciency , η_max = %.2f percent' %n_max)
print('Case(d): Load fraction from fixed losses and rated variable losses , L.F = %.3f*rated' %LF_d)
```

In [1]:

```
#Variable declaration
V = 240.0 #Voltage rating of dc shunt motor(V)
hp = 25.0 #Power rating of dc shunt motor(hp)
S = 1100.0 #Speed of the dc shunt motor(rpm)
R_a = 0.15 #Armture resistance(ohm)
R_f = 80.0 #Field resistance(ohm)
I_L = 89.0 #Rated line current(A)
#Calculation
V_f = V #Voltage across field winding(V)
I_f = V_f/R_f #Field current(A)
I_a = I_L-I_f #Armature current(A)
P_o = hp*746 #Power rating of dc shunt motor(W)
V_a = V #Voltage across armature(V)
E_c_fl = V_a-I_a*R_a #Back EMF(V)
E_c = E_c_fl
P_d = E_c*I_a #Power developed by the armature(W)
P_r = P_d-P_o #Full-load rotational losses(W)
P_in = V*I_L #Input power(W)
n = P_o/P_in*100 #Full-load efficiency(%)
P_k = V_f*I_f+P_r #Total constant losses(W)
Ia = (P_k/R_a)**0.5 #Armature current for maximum efficiency(A)
I_a_rated = I_a
LF = Ia/I_a_rated #Load fraction at which max efficiency is produced
rated_input = V*I_L
n_max = ((LF*rated_input)-2*P_k)/(LF*rated_input)*100 #Maximum efficiency(%)
#Result
print('Case(a): Power developed by the armature , P_d = %.1f W' %P_d)
print('Case(b): Full-load rotational losses , P_r = %.1f W' %P_r)
print('Case(c): Full-laod efficiency , η = %.1f percent' %n)
print('Case(d): Total constant losses , P_k = %.1f W' %P_k)
print('Case(e): Armature current from maximum efficiency , I_a = %.1f A' %Ia)
print('Case(f): Load fraction at which maximum efficiency is produced , L.F = %.1f ' %LF)
print('Case(g): Maximum efficiency , η_max = %.1f percent' %n_max)
```

In [1]:

```
#Variable declaration
V = 240.0 #Voltage rating of dc shunt motor(V)
hp = 25.0 #Power rating of dc shunt motor(hp)
S = 1100.0 #Speed of the dc shunt motor(rpm)
R_a = 0.15 #Armture resistance(ohm)
R_f = 80.0 #Field resistance(ohm)
I_L = 89.0 #Rated line current(A)
#Calculation
V_f = V #Voltage across field winding(V)
I_f = V_f/R_f #Field current(A)
I_a = I_L-I_f #Armature current(A)
P_o = hp*746 #Power rating of dc shunt motor(W)
V_a = V #Voltage across armature(V)
E_c_fl = V_a-I_a*R_a #Back EMF(V)
E_c = E_c_fl
P_d = E_c*I_a #Power developed by the armature(W)
P_r = P_d-P_o #Full-load rotational losses(W)
P_in = V*I_L #Input power(W)
n = P_o/P_in*100 #Full-load efficiency(%)
P_k = V_f*I_f+P_r #Total constant losses(W)
Ia = (P_k/R_a)**0.5 #Armature current for maximum efficiency(A)
I_a_rated = I_a
LF = Ia/I_a_rated #Load fraction at which max efficiency is produced
rated_input = V*I_L
n_max = ((LF*rated_input)-2*P_k)/(LF*rated_input)*100 #Maximum efficiency(%)
#Result
print('Case(a): Power developed by the armature , P_d = %.1f W' %P_d)
print('Case(b): Full-load rotational losses , P_r = %.1f W' %P_r)
print('Case(c): Full-laod efficiency , η = %.1f percent' %n)
print('Case(d): Total constant losses , P_k = %.1f W' %P_k)
print('Case(e): Armature current from maximum efficiency , I_a = %.1f A' %Ia)
print('Case(f): Load fraction at which maximum efficiency is produced , L.F = %.1f ' %LF)
print('Case(g): Maximum efficiency , η_max = %.1f percent' %n_max)
```

In [1]:

```
#Variable declaration
V = 240.0 #Voltage rating of dc shunt motor(V)
hp = 5.0 #Power rating of dc shunt motor(hp)
S_fl = 1100.0 #Speed of the dc shunt motor(rpm)
R_a = 0.4 #Armture resistance(ohm)
R_f = 240.0 #Field resistance(ohm)
n = 0.75 #Full-load efficiency
#Calculation
#Case(a)
V_L = V #Load voltage(V)
P_o = hp*746 #Power rating of dc shunt motor(W)
I_L = P_o/(n*V_L) #Rated input line current(A)
V_f = V #Voltage across field winding(V)
I_f = V_f/R_f #Field current(A)
I_a = I_L-I_f #Armature current(A)
#Case(b)
V_a = V #Voltage across armature(V)
E_c_fl = V_a-I_a*R_a #Back EMF(V)
E_c = E_c_fl
P_d = E_c*I_a #Power developed in the armature at rated load(W)
#Case(c)
P_r = P_d-P_o #Rotational losses at rated load(W)
#Case(d)
P_o_nl = 0 #At no-load
P_r_nl = P_r #Rotational losses at no load(W)
P_d_nl = P_r_nl
#Case(e)
I_a_nl = P_d_nl/V_a #No-load armature current(A)
#Case(f)
E_c_nl = V #No-load voltage(V)
E_c_fl = E_c #Full-load voltage(V)
S_nl = E_c_nl/E_c_fl*S_fl #No-load speed(rpm)
#Case(g)
SR = (S_nl-S_fl)/S_fl*100 #Speed regulation(%)
#Result
print('Case(a): Rated input line current , I_L = %.2f A' %I_L)
print(' Rated armature current , I_a = %.2f A' %I_a)
print('Case(b): Power developed in the armature at rated load , P_d = %d W' %P_d)
print('Case(c): Rotational losses at rated load , P_r = %d W' %P_r)
print('Case(d): Rotational losses at no load , P_r = %d W' %P_r_nl)
print('Case(e): No-load armature current , I_a(nl) = %.2f A' %I_a_nl)
print('Case(f): No-load speed , S_nl = %.f rpm' %S_nl)
print('Case(g): Speed regulation of the motor , SR = %.1f percent' %SR)
```

In [1]:

```
#Variable declaration
V = 240.0 #Voltage rating of dc shunt motor(V)
I_L = 55.0 #Rated line current(A)
S = 1200.0 #Speed of the dc shunt motor(rpm)
P_r = 406.4 #Rotational losses at rated load(W)
R_f = 120.0 #Field resistance(ohm)
R_a = 0.4 #Armture resistance(ohm)
#Calculation
#Case(a)
V_f = V #Voltage across field winding(V)
I_f = V_f/R_f #Field current(A)
I_a = I_L-I_f #Armature current(A)
V_a = V #Voltage across armature(V)
E_c = V_a-I_a*R_a #Back EMF(V)
P_d = E_c*I_a #Power developed by the armature at rated load(W)
#Case(b)
P_o = P_d-P_r #Rated output power(W)
P_o_hp = P_o/746 #Rated output power(hp)
#Case(c)
T_o = P_o_hp*5252/S #Rated output torque(lb-ft)
T_o_Nm = T_o*1.356 #Rated output torque(N-m)
#Case(d)
P_in = V*I_L #Input power(W)
n = (P_o/P_in)*100 #Efficiency at rated load(%)
#Case(e)
P_o_nl = 0 #At no-load
P_r_nl = P_r #Rotational losses at no load(W)
P_d_nl = P_r_nl
I_a_nl = P_r_nl/V_a #No-load armature current(A)
E_c_nl = V #No-load voltage(V)
E_c_fl = E_c #Full-load voltage(V)
S_fl = S #Full-load speed(rpm)
S_nl = E_c_nl/E_c_fl*S_fl #No-load speed(rpm)
#Case(f)
SR = (S_nl-S_fl)/S_fl*100 #Speed regulation(%)
#Result
print('Case(a): Counter EMF , E_c = %.1f V' %E_c)
print(' Power developed at rated load , P_d = %.1f W' %P_d)
print('Case(b): Rated output power , P_o = %d W' %P_o)
print(' Rated output power , P_o = %d hp' %P_o_hp)
print('Case(c): Rated output torque , T_o = %.2f lb-ft' %T_o)
print(' Rated output torque , T_o = %d N-m' %T_o_Nm)
print('Case(d): Efficiency at rated load , η = %.1f percent' %n)
print('Case(e): No-load armature current , I_a(nl) = %.3f A' %I_a_nl)
print(' No-load speed , S_nl = %.f rpm' %S_nl)
print('Case(e): Speed regulation , SR = %.1f percent' %SR)
```

In [1]:

```
#Variable declaration
V = 125.0 #Voltage rating of generator(V)
P_o = 12500.0 #Power rating of generator(W)
P_hp = 20.0 #Power rating of motor(hp)
R_a = 0.1 #Armature resistance(ohm)
R_f = 62.5 #Field resistance(ohm)
P_var = 1040.0 #Rated variable electric loss(W)
#Calculation
#Case(a)
P_in = P_hp*746 #Power input to generator(W)
n = P_o/P_in*100 #Efficiency(%)
#Case(b)
V_f = V #Voltage across shunt field winding(V)
P_sh_loss = V_f**2/R_f #Shunt field loss(W)
#Case(c)
V_L = V
I_L = P_o/V_L #Line current(A)
I_f = V_f/R_f #Field current(A)
I_a = I_L+I_f #Armature current(A)
E_g = V_L+I_a*R_a #Generated EMF(V)
P_d1 = E_g*I_a #Generated electric power(W)
P_f = V_f*I_f
P_d2 = P_o+P_var+P_f #Generated electric power(W)
#Case(d)
P_d = P_d1
P_r = P_in-P_d #Rotational power loss(W)
#Case(e)
P_k = P_r+V_f*I_f #Constant losses(W)
Ia = (P_k/R_a)**0.5 #Armature current for max efficiency(A)
#Case(f)
I_a_rated = I_a #Rated armature current(A)
LF = Ia/I_a_rated #Load fraction
#Case(g)
rated_output = 12500 #Rated output(W)
n_max = (LF*rated_output)/((LF*rated_output)+(2*P_k))*100 #Maximum efficiency
#Result
print('Case(a): Efficiency , η = %.f percent' %n)
print('Case(b): Shunt field loss = %d W' %P_sh_loss)
print('Case(c): Generated electric power , P_d = %d W (Method 1)' %P_d1)
print(' Generated electric power , P_d = %d W (Method 2)' %P_d2)
print('Case(d): Rotational power loss , P_r = %.f W' %P_r)
print('Case(e): Armature current for maximum efficiency , I_a = %.1f A' %Ia)
print('Case(f): Load fraction for maximum efficiency , L.F = %.2f ' %LF)
print('Case(g): Maximum efficiency , η = %.2f percent' %n_max)
```

In [1]:

```
#Variable declaration
V = 125.0 #Voltage rating of generator(V)
P_o = 12500.0 #Power rating of generator(W)
P_hp = 20.0 #Power rating of motor(hp)
R_a = 0.1 #Armature resistance(ohm)
R_f = 62.5 #Field resistance(ohm)
P_var = 1040.0 #Rated variable electric loss(W)
P_k = 1380.0 #Constant losses(W)
LF_a = 25.0/100 #At rated output
LF_b = 50.0/100 #At rated output
LF_c = 75.0/100 #At rated output
LF_d = 125.0/100 #At rated output
#Calculation
output = P_o
P_a_rated = P_var
n_a = output*LF_a/(output*LF_a+P_k+(LF_a**2)*P_a_rated)*100 #Efficiency of dc shunt generator(%)
n_b = output*LF_b/(output*LF_b+P_k+(LF_b**2)*P_a_rated)*100 #Efficiency of dc shunt generator(%)
n_c = output*LF_c/(output*LF_c+P_k+(LF_c**2)*P_a_rated)*100 #Efficiency of dc shunt generator(%)
n_d = output*LF_d/(output*LF_d+P_k+(LF_d**2)*P_a_rated)*100 #Efficiency of dc shunt generator(%)
#Result
print('Case(a): Efficiency of dc generator at 25 percent rated output , η = %.1f percent' %n_a)
print('Case(b): Efficiency of dc generator at 50 percent rated output , η = %.1f percent' %n_b)
print('Case(c): Efficiency of dc generator at 75 percent rated output , η = %.1f percent' %n_c)
print('Case(d): Efficiency of dc generator at 125 percent rated output , η = %.2f percent' %n_d)
print('\nNOTE: Calculation error in textbook for case(b)')
```

In [1]:

```
#Variable declaration
kVA = 100.0 #Rating of the alternator(kVA)
V = 1100.0 #Rated voltage of the alternator(V)
I_a_nl = 8.0 #No-load armature current(A)
P_in_nl = 6000.0 #No-load Power input to the armature(W)
V_oc = 1350.0 #Open-circuit line voltage(V)
I_f = 18.0 #Field current(A)
V_f = 125.0 #Voltage across field winding(V)
R_a = 0.45 #Armature resistance(ohm/phase)
I_a_rated = 52.5 #Rated armature current(A)
#Calculation
#Case(a)
P_r = P_in_nl-3*(I_a_nl)**2*R_a #Rotational loss of synchronous dynamo(W)
#Case(b)
P_f = V_f*I_f #Field copper loss(W)
#Case(c)
P_k = P_r+P_f #Fixed losses at rated synchronous speed(W)
#Case(d)
P_cu = 3*(I_a_rated)**2*R_a #Electric armature copper loss at rated load(W)
LF1 = 1.0/4 #Load fraction
LF2 = 1.0/2 #Load fraction
LF3 = 3.0/4 #Load fraction
P_cu_LF1 = P_cu*(LF1)**2 #Electric armature copper loss at 1/4 load(W)
P_cu_LF2 = P_cu*(LF2)**2 #Electric armature copper loss at 1/2 load(W)
P_cu_LF3 = P_cu*(LF3)**2 #Electric armature copper loss at 3/4 load(W)
#Case(e)
PF = 0.9 #Power factor lagging
n_1 = (LF1*kVA*1000*PF)/((LF1*kVA*1000*PF)+P_k+P_cu_LF1)*100 #Efficiency at 1/4 load
n_2 = (LF2*kVA*1000*PF)/((LF2*kVA*1000*PF)+P_k+P_cu_LF2)*100 #Efficiency at 1/2 load
n_3 = (LF3*kVA*1000*PF)/((LF3*kVA*1000*PF)+P_k+P_cu_LF3)*100 #Efficiency at 3/4 load
n_fl = (kVA*1000*PF)/((kVA*1000*PF)+P_k+P_cu)*100 #Efficiency at rated load
#Case(f)
I_a_max = (P_k/(3*R_a))**0.5 #Armature current for max efficiency at 0.9 PF lagging(A)
LF = I_a_max/I_a_rated #Load fraction for max efficiency
n_max = (LF*kVA*1000*PF)/((LF*kVA*1000*PF)+2*P_k)*100 #Max Efficiency 0.9 PF lagging(%)
#Case(g)
P_o = kVA*PF #Output power at 0.9 PF lagging(kW)
I_a = I_a_rated
P_d = P_o+(3*(I_a)**2*R_a/1000)+(V_f*I_f/1000) #Armature power developed at 0.9 PF lagging at full-load(kW)
#Result
print('Case(a): Rotational loss of the synchronous dynamo , P_r = %.f W' %P_r)
print('Case(b): Field copper loss , P_f = %.f W' %P_f)
print('Case(c): Fixed losses at rated synchronous speed , P_k = %.f W' %P_k)
print('Case(d): Electric armature copper loss at 1/4 rated load , P_cu = %.1f W' %P_cu_LF1)
print(' Electric armature copper loss at 1/2 rated load , P_cu = %.1f W' %P_cu_LF2)
print(' Electric armature copper loss at 3/4 rated load , P_cu = %.f W' %P_cu_LF3)
print(' Electric armature copper loss at rated load , P_cu = %.f W' %P_cu)
print('Case(e): Efficiency at 1/4 rated load , η = %.1f percent' %n_1)
print(' Efficiency at 1/2 rated load , η = %.1f percent' %n_2)
print(' Efficiency at 3/4 rated load , η = %.1f percent' %n_3)
print(' Efficiency at rated load , η = %.1f percent' %n_fl)
print('Case(f): Maximum efficiency at 0.9 PF lagging , η_max = %.1f percent' %n_max)
print('Case(g): Armature power developed at 0.9 PF lagging at full load , P_d = %.2f kW' %P_d)
```

In [1]:

```
#Variable declaration
kVA = 1000.0 #Rating of the alternator(kVA)
V = 2300.0 #Rated voltage of the alternator(V)
hp = 100.0 #Power rating of the dc motor(hp)
V_motor = 240.0 #Rated voltage of the motor(V)
P_1 = 7.5 #Motor output(kW). TEST 1
P_2 = 16.0 #Motor output(kW). TEST 2
VfIf = 14.0 #Field losses(kW)
P_f = VfIf #Field losses(kW)
P_3 = 64.2 #Motor output(kW). TEST 3
I_sc = 251.0 #Short circuit current(A)
V_L = 1443.0 #Line voltage(V). TEST 4
R_a = 0.3 #Armature resistance(ohm)
#Calculation
#Case(a)
P_r = P_2 #Rotational losses(kW). From TEST 2
#Case(b)
P_cu = P_3-P_1 #Full-load armature copper loss(kW)
#Case(c)
E_gL = V_L #Generated line voltage(V)
Z_s = (E_gL/3**0.5)/I_sc #Synchronous impedance of the armature(ohm)
#Case(d)
X_s = (Z_s**2-R_a**2)**0.5 #Synchronous reactance of the armature(ohm)
#Case(e)
PF = 0.8 #Lagging power factor
sin_theta = (1-PF**2)**0.5 #Sinθ
V_p = V/3**0.5 #Phase voltage(V)
I_a = I_sc #Armature current(A)
E_gp = complex((V_p*PF+I_a*R_a),(V_p*sin_theta+I_a*X_s)) #Generated phase voltage(V)
V_nl = abs(E_gp) #No-load voltage(V)
V_fl = V_p #Full-load voltage(V)
VR = (V_nl-V_fl)/V_fl*100 #Alternator voltage regulation(%)
#Case(f)
LF = 1.0 #Load fraction
n_rated = (LF*kVA*PF)/((LF*kVA*PF)+(P_f+P_r)+P_cu)*100 #Efficiency at 0.8 lagging PF(%)
#Case(g)
P_k = (P_f+P_r) #Constant losses(kW)
L_F = (P_k/P_cu)**0.5 #Load fraction for max efficiency
n_max = (L_F*kVA*PF)/((L_F*kVA*PF)+2*P_k)*100 #Max Efficiency at 0.8 lagging PF(%)
#Case(h)
PF_h = 1.0 #Unity PF
P_o = kVA*PF_h #Output power(kW)
P_d = P_o+(3*(I_a)**2*R_a/1000)+(VfIf) #Armature power developed at rated-load unity PF(kW)
#Result
print('Case(a): Rotational losses , P_r = %.1f kW' %P_r)
print('Case(b): Full-load armature copper loss , P_cu = %.1f kW' %P_cu)
print('Case(c): Synchronous impedance of the armature , Z_s = %.2f Ω' %Z_s)
print('Case(d): Synchronous reactance of the armature , jX_s = %.2f Ω' %X_s)
print('Case(e): Alternator voltage regulation at 0.8 PF lagging , VR = %.2f percent' %VR)
print('Case(f): Alternator efficiency at 0.8 PF lagging at rated load , η_rated = %.1f percent' %n_rated)
print('Case(g): Maximum efficiency at 0.8 PF lagging , η_max = %.2f percent' %n_max)
print('Case(h): Power developed by the alternator armature at rated load, unity PF , P_d = %.f kW' %P_d)
```

In [1]:

```
#Variable declaration
P = 4.0 #Number of poles in Induction motor
f = 60.0 #Frequency(Hz)
V = 220.0 #Rated voltage of IM(V)
hp_IM = 5.0 #Power rating of IM(hp)
PF = 0.9 #Power factor
I_L = 16.0 #Line current(A)
S = 1750.0 #Speed of IM(rpm)
I_nl = 6.5 #No-load line current(A)
V_nl = 220.0 #No-load line voltage(V)
P_nl = 300.0 #No-load power reading(W)
I_br = 16.0 #Blocked rotor line current(A)
V_br = 50.0 #Blocked rotor voltage(V)
P_br = 800.0 #Blocked rotor power reading(W)
#Calculation
#Case(a)
P_cu = P_br #Full-load equivalent copper loss(W)
I_1 = I_br #Primary current(A)
R_e1 = P_cu/(3.0/2*I_1**2) #Equivalent total resistance of IM(ohm)
#Case(b)
P_in = P_nl #Input power to IM(W)
I1 = I_nl #Input current(A)
P_r = P_in-(3.0/2*I1**2*R_e1) #Rotational losses(W)
#Case(c)
LF1 = 1.0/4 #Load fraction
LF2 = 1.0/2 #Load fraction
LF3 = 3.0/4 #Load fraction
LF4 = 5.0/4 #Load fraction
P_cu_LF1 = LF1**2*P_cu #Equivalent copper loss at 1/4 rated-load(W)
P_cu_LF2 = LF2**2*P_cu #Equivalent copper loss at 1/2 rated-load(W)
P_cu_LF3 = LF3**2*P_cu #Equivalent copper loss at 3/4 rated-load(W)
P_cu_LF4 = LF4**2*P_cu #Equivalent copper loss at 5/4 rated-load(W)
#Case(d)
Full_load_input = 3**0.5*V*I_L*PF #Full-load input(W)
n_rated = (Full_load_input-(P_r+P_cu))/(Full_load_input)*100 #Efficiency at rated load(%)
n_LF1 = (Full_load_input*LF1-(P_r+P_cu_LF1))/(Full_load_input*LF1)*100 #Efficiency at 1/4 rated load(%)
n_LF2 = (Full_load_input*LF2-(P_r+P_cu_LF2))/(Full_load_input*LF2)*100 #Efficiency at 1/2 rated load(%)
n_LF3 = (Full_load_input*LF3-(P_r+P_cu_LF3))/(Full_load_input*LF3)*100 #Efficiency at 3/4 rated load(%)
n_LF4 = (Full_load_input*LF4-(P_r+P_cu_LF4))/(Full_load_input*LF4)*100 #Efficiency at 5/4 rated load(%)
#Case(e)
P_o = (Full_load_input*n_rated/100)/746 #Output hp at 1/4 rated load
P_o_LF1 = (Full_load_input*LF1*n_LF1/100)/746 #Output hp at 1/4 rated load
P_o_LF2 = (Full_load_input*LF2*n_LF2/100)/746 #Output hp at 1/2 rated load
P_o_LF3 = (Full_load_input*LF3*n_LF3/100)/746 #Output hp at 3/4 rated load
P_o_LF4 = (Full_load_input*LF4*n_LF4/100)/746 #Output hp at 5/4 rated load
#Case(f)
hp = P_o #Rated output(hp)
T_o = P_o*5252/S #Output torque at full-load(lb-ft)
T_o_Nm = T_o*1.356 #Output torque at full-load(N-m)
#Result
print('Case(a): Equivalent total resistance of IM between lines , R_e1 = %.3f Ω' %R_e1)
print('Case(b): Rotational losses , P_r = %.f W' %P_r)
print('Case(c): Equivalent copper loss at full-load , P_cu = %d W' %P_cu)
print(' Equivalent copper loss at 1/4 rated load , P_cu = %d W' %P_cu_LF1)
print(' Equivalent copper loss at 1/2 rated load , P_cu = %d W' %P_cu_LF2)
print(' Equivalent copper loss at 3/4 rated load , P_cu = %d W' %P_cu_LF3)
print(' Equivalent copper loss at 5/4 rated load , P_cu = %d W' %P_cu_LF4)
print('Case(d): Efficiency at rated load , η = %.1f percent' %n_rated)
print(' Efficiency at 1/4 rated load , η = %.1f percent' %n_LF1)
print(' Efficiency at 1/2 rated load , η = %.1f percent' %n_LF2)
print(' Efficiency at 3/4 rated load , η = %.1f percent' %n_LF3)
print(' Efficiency at 5/4 rated load , η = %.1f percent' %n_LF4)
print('Case(e): Output horsepower at rated load , P_o = %.2f hp' %P_o)
print(' Output horsepower at 1/4 rated load , P_o = %.3f hp' %P_o_LF1)
print(' Output horsepower at 1/2 rated load , P_o = %.3f hp' %P_o_LF2)
print(' Output horsepower at 3/4 rated load , P_o = %.2f hp' %P_o_LF3)
print(' Output horsepower at 5/4 rated load , P_o = %.2f hp' %P_o_LF4)
print('Case(f): Output torque at full-load , T_o = %.1f lb-ft' %T_o)
print(' Output torque at full-load , T_o = %.2f N-m' %T_o_Nm)
```

In [1]:

```
#Variable declaration
pole = 4.0 #Number of poles in Induction motor
f = 60.0 #Frequency(Hz)
V = 220.0 #Rated voltage of IM(V)
hp_IM = 5.0 #Power rating of IM(hp)
PF = 0.9 #Power factor
I_L = 16.0 #Line current(A)
S_r = 1750.0 #Speed of IM(rpm)
I_nl = 6.5 #No-load line current(A)
V_nl = 220.0 #No-load line voltage(V)
P_nl = 300.0 #No-load power reading(W)
I_br = 16.0 #Blocked rotor line current(A)
V_br = 50.0 #Blocked rotor voltage(V)
P_br = 800.0 #Blocked rotor power reading(W)
R_dc = 1.0 #DC resistance between lines(ohm)
V = 220.0 #Voltage rating(V)
P_input = 5500.0 #Power drawn(W)
#Calculation
R_e1 = 1.25*R_dc #Equivalent total resistance of IM(ohm)
P_in = P_nl #Input power to IM(W)
I1 = I_nl #Input current(A)
P_r = P_in-(3.0/2*(I1)**2*R_e1) #Rotational losses(W)
I_1 = I_L
SCL_fl = 3.0/2*(I_1)**2*R_e1 #Stator copper loss at full-load(W)
SPI = P_input #Stator power input(W)
RPI = SPI-SCL_fl #Rotor power input(W)
S = (120*f/pole) #Speed of synchronous magnetic field(rpm)
s = (S-S_r)/S #Slip
RPD_fl = RPI*(1-s) #Rotor power developed(W)
RPO_fl = RPD_fl-P_r #Rotor power output(W)
#Case(a)
P_o = RPO_fl
n_fl = (P_o/P_input)*100 #Full-load efficiency(%)
#Case(b)
hp = P_o/746 #Output horsepower at full load
T_o = hp*5252/S_r #Output torque(lb-ft)
T_o_Nm = T_o*1.356 #Output torque(N-m)
#Result
print('Case(a): Full-load efficiency , η_fl = %.1f percent' %n_fl)
print('Case(b): Output horsepower , hp = %.2f hp at full load' %hp)
print(' Output torque , T_o = %.1f lb-ft = %.1f N-m' %(T_o,T_o_Nm))
print('Case(c): Comparison of results')
print('\t\t\t\t Ex. 12-14 \t\t Ex. 12-15')
print('________________________________________________________________________')
print('η_fl(percent)\t\t\t 82.4 \t\t\t %.1f' %n_fl)
print('Rated output(hp)\t\t 6.06 \t\t\t %.2f' %hp)
print('Rated output torque(lb-ft)\t 18.2 \t\t\t %.1f' %T_o)
```

In [1]:

```
import math
import cmath
import numpy
#Variable declaration
P = 6.0 #Number of poles in SCIM
S_r = 1176.0 #Rated rotor speed(rpm)
V = 220.0 #Voltage rating of SCIM(V)
f = 60.0 #Frequency(Hz)
P_hp = 7.5 #Power rating of SCIM(hp)
R_ap = 0.3 #Armature resistance(ohm)
R_r = 0.144 #Rotor resistance(ohm)
jXm = 13.5 #Reactance(ohm)
jXs = 0.5 #Synchronous reactance(ohm)
jXlr = 0.2 #Locked rotor reactance(ohm)
P_r = 300.0 #Total rotational losses(W)
#Calculation
#Case(a)
S = 120*f/P #Speed of the rotating magnetic field(rpm)
s = (S-S_r)/S #Slip
R_r_s = R_r/s
V_p = V/3**0.5 #Voltage per phase(V)
I1_1 = complex(R_ap,jXm+jXs)
I1_2 = complex(0,-jXm)
I2_1 = complex(0,-jXm)
I2_2 = complex(R_r/s,jXm+jXlr)
V_1 = V_p
V_2 = 0
A = [[I1_1,I2_1],[I1_2,I2_2]] #Matrix containing above mesh eqns array
delta = numpy.linalg.det(A) #Determinant of A
#Case(b)
I_p = numpy.linalg.det([[V_1,I2_1],[V_2,I2_2]])/delta #Stator armature current(A)
I_1 = I_p
#Case(c)
I_r = numpy.linalg.det([[I1_1,V_1],[I1_2,V_2]])/delta #Rotor armature current(A)
I_2 = I_r
#Case(d)
theta_1 = cmath.phase(I_p)*180/math.pi #Motor PF angle(degrees)
cos_theta1 = math.cos(theta_1*math.pi/180) #Motor PF
#Case(e)
SPI = V_p*abs(I_p)*cos_theta1 #Stator power input(W)
#Case(f)
SCL = abs(I_p)**2*R_ap #Stator Copper Loss(W)
#Case(g)
RPI = SPI-SCL #Rotor power input(W) Method 1
RPI_2 = abs(I_r)**2*(R_r/s) #Rotor power input(W) Method 2
#Case(h)
RCL = s*RPI #Rotor copper losses(W)
#Case(i)
RPD_1 = RPI-RCL #Rotor power developed(W) Method 1
RPD_2 = RPI*(1-s) #Rotor power developed(W) Method 2
#Case(j)
RPO = 3*RPD_1-P_r #Total three-phase rotor power output(W)
#Case(k)
P_to = RPO #Total rotor power at the motor pulley(W)
T_o = 7.04*(P_to/S_r) #Total 3-phase torque(lb-ft)
#Case(l)
hp = P_to/746.0 #Output horsepower(hp)
#Case(m)
P_in = 3*SPI #Input power to stator(W)
n = P_to/P_in*100 #Motor efficiency at rated load(%)
#Result
print('Case(a): Slip , s = %.2f' %s)
print(' R_r/s = %.1f Ω' %R_r_s)
print('Case(b): Stator armature current per phase , I_p = %.2f∠%.2f° A' %(abs(I_p),cmath.phase(I_p)*180/math.pi))
print('Case(c): Rotor current per phase , I_r = %.1f∠%.2f° A' %(abs(I_r),cmath.phase(I_r)*180/math.pi))
print('Case(d): Motor power factor , cosӨ = %.3f' %cos_theta1)
print('Case(e): Stator power input per phase , SPI = %d W' %SPI)
print('Case(f): Stator copper loss per phase , SCL = %.1f W' %SCL)
print('Case(g): Rotor power input per phase , RPI = %.2f W (Method 1)' %RPI)
print(' Rotor power input per phase , RPI = %.2f W (Method 2)' %RPI_2)
print('Case(h): Rotor copper loss per phase , RCL = %.1f W' %RCL)
print('Case(i): Rotor power developed per phase , RPD = %.1f W (Method 1)' %RPD_1)
print(' Rotor power developed per phase , RPD = %.1f W (Method 2)' %RPD_2)
print('Case(j): Total three-phase rotor power output at shaft , RPO = %.1f W' %RPO)
print('Case(k): Total torque developed at output , T_o = %.2f lb-ft' %T_o)
print('Case(l): Horsepower output , hp = %.2f hp' %hp)
print('Case(m): Efficiency at rated load , η = %.2f percent' %n)
print('Case(n): Power flow diagram is shown in textbook Fig. 12-12 page no 441')
print('\nNOTE: Changes in obtained answer from that of textbook is due to more precision i.e more number of decimal places')
```

In [1]:

```
#Variable declaration
V = 220.0 #Voltage rating of SCIM(V)
P_hp = 7.5 #Power rating of SCIM(hp)
kVA_up_limit = 7.99 #Upper limit of starting kVA/hp
kVA_low_limit = 7.1 #Lower limit of starting kVA/hp
#Calculation
I_s_u = kVA_up_limit*P_hp*1000/(3**0.5*V) #Upper limit of starting current(A)
I_s_l = kVA_low_limit*P_hp*1000/(3**0.5*V) #Lower limit of starting current(A)
#Result
print('Case(a): Upper limit of the starting current , I_s = %.1f A' %I_s_u)
print('Case(b): Lower limit of the starting current , I_s = %.1f A' %I_s_l)
```

In [1]:

```
import math
import cmath
import numpy
#Variable declaration
P = 6.0 #Number of poles in SCIM
S_r = 1176.0 #Rated rotor speed(rpm)
V = 220.0 #Voltage rating of SCIM(V)
f = 60.0 #Frequency(Hz)
P_hp = 7.5 #Power rating of SCIM(hp)
R_ap = 0.3 #Armature resistance(ohm)
R_r = 0.144 #Rotor resistance(ohm)
jXm = 13.5 #Reactance(ohm)
jXs = 0.5 #Synchronous reactance(ohm)
jXlr = 0.2 #Locked rotor reactance(ohm)
P_r = 300.0 #Total rotational losses(W)
s = 1.0 #Unity slip
#Calculation
R_r_s = R_r/s
V_p = V/3**0.5 #Voltage per phase(V)
I1_1 = complex(R_ap,jXm+jXs)
I1_2 = complex(0,-jXm)
I2_1 = complex(0,-jXm)
I2_2 = complex(R_r/s,jXm+jXlr)
V_1 = V_p
V_2 = 0
A = [[I1_1,I2_1],[I1_2,I2_2]] #Matrix containing above mesh eqns array
delta = numpy.linalg.det(A) #Determinant of A
#Case(a)
I_s = numpy.linalg.det([[V_1,I2_1],[V_2,I2_2]])/delta #Stator armature current(A)
I_1 = I_s
#Case(b)
theta = cmath.phase(I_s)*180/math.pi #Phase angle of Stator armature current(degree)
cos_theta = math.cos(theta*math.pi/180) #PF of the motor at starting
#Result
print('Case(a): Starting stator current of the SCIM , I_s = I_1 = %.1f∠%.1f° A' %(abs(I_s),theta))
print('Case(b): Power factor of the motor at starting , cosθ = %.3f ' %cos_theta)
```

In [1]:

```
#Variable declaration
V = 220.0 #Rated voltage of SCIM(V)
f = 60.0 #Frequency(Hz)
P = 4.0 #Number of poles
PF = 0.85 #Power factor of capacitor-start IM
hp_IM = 5.0 #Power rating of IM(hp)
I_L = 28.0 #Rated line current(A)
S_r = 1620.0 #Rotor speed of IM(rpm)
I_nl = 6.4 #No-load line current(A)
V_nl = 220.0 #No-load line voltage(V)
P_nl = 239.0 #No-load power reading(W)
s_nl = 0.01 #No-load slip
I_br = 62.0 #Blocked rotor line current(A)
V_br = 64.0 #Blocked rotor voltage(V)
P_br = 1922.0 #Blocked rotor power reading(W)
s_br = 1.0 #Blocked rotor slip
#Calculation
#Case(a)
R_els = P_br/I_br**2 #Equivalent total resistance of IM(ohm)
#Case(b)
P_in = P_nl #Input power to IM(W)
I_ls = I_nl #Input current(A)
P_ro = P_in-(I_ls**2*R_els) #Rotational losses(W)
#Case(c)
S = (120*f/P) #Speed of synchronous magnetic field(rpm)
S_fl = S_r #Full-load rotor speed of IM(rpm)
s_fl = (S-S_fl)/S #Full-load Slip
LF1 = 1.0/4 #Load fraction
LF2 = 1.0/2 #Load fraction
LF3 = 3.0/4 #Load fraction
LF4 = 5.0/4 #Load fraction
s_LF1 = s_fl*LF1 #slip at 1/4 rated load
s_LF2 = s_fl*LF2 #slip at 1/2 rated load
s_LF3 = s_fl*LF3 #slip at 3/4 rated load
s_LF4 = s_fl*LF4 #slip at 5/4 rated load
#Case(d)
s_o = s_nl #No-load slip
P_rs_fl = P_ro*(1-s_fl)/(1-s_o) #Rotational losses rated load(W)
P_rs_LF1 = P_ro*(1-s_LF1)/(1-s_o) #Rotational losses at 1/4 rated load(W)
P_rs_LF2 = P_ro*(1-s_LF2)/(1-s_o) #Rotational losses at 1/2 rated load(W)
P_rs_LF3 = P_ro*(1-s_LF3)/(1-s_o) #Rotational losses at 3/4 rated load(W)
P_rs_LF4 = P_ro*(1-s_LF4)/(1-s_o) #Rotational losses at 5/4 rated load(W)
#Case(e)
Ils = I_L #Line current(A)
P_cu_fl = Ils**2*R_els #Equivalent copper loss at full-load slip(W)
P_cu_LF1 = LF1**2*P_cu_fl #Equivalent copper loss at 1/4 rated load(W)
P_cu_LF2 = LF2**2*P_cu_fl #Equivalent copper loss at 1/2 rated load(W)
P_cu_LF3 = LF3**2*P_cu_fl #Equivalent copper loss at 3/4 rated load(W)
P_cu_LF4 = LF4**2*P_cu_fl #Equivalent copper loss at 5/4 rated load(W)
#Case(f)
Input = V*I_L*PF #Input to single phase capacitor start IM(W)
n_LF1 = (Input*LF1-(P_rs_LF1+P_cu_LF1))/(Input*LF1)*100 #Efficiency at 1/4 rated load(%)
n_LF2 = (Input*LF2-(P_rs_LF2+P_cu_LF2))/(Input*LF2)*100 #Efficiency at 1/2 rated load(%)
n_LF3 = (Input*LF3-(P_rs_LF3+P_cu_LF3))/(Input*LF3)*100 #Efficiency at 3/4 rated load(%)
n_LF4 = (Input*LF4-(P_rs_LF4+P_cu_LF4))/(Input*LF4)*100 #Efficiency at 5/4 rated load(%)
n_fl = (Input-(P_rs_fl+P_cu_fl))/(Input)*100 #Efficiency at full load(%)
#Case(g)
P_o_LF1 = (Input*LF1*n_LF1/100)/746 #Output hp at 1/4 rated load
P_o_LF2 = (Input*LF2*n_LF2/100)/746 #Output hp at 1/2 rated load
P_o_LF3 = (Input*LF3*n_LF3/100)/746 #Output hp at 3/4 rated load
P_o_LF4 = (Input*LF4*n_LF4/100)/746 #Output hp at 5/4 rated load
P_o = (Input*n_fl/100)/746 #Output hp at rated load
#Case(h)
hp = P_o #Rated output horsepower
S_fl = S_r #Full-load rotor speed(rpm)
T_o = P_o*5252/S_fl #Output torque at full-load(lb-ft)
T_o_ST = T_o*1.356 #Output torque at full-load(N-m)
#Result
print('Case(a): Equivalent total resistance of motor between lines , R_els = %.1f Ω' %R_els)
print('Case(b): Rotational losses at no load , P_ro = %.1f W' %P_ro)
print('Case(c): Slip at rated load , s_fl = %.1f ' %s_fl)
print(' Slip at 1/4 rated load , s = %.3f ' %s_LF1)
print(' Slip at 1/2 rated load , s = %.2f ' %s_LF2)
print(' Slip at 3/4 rated load , s = %.3f ' %s_LF3)
print(' Slip at 5/4 rated load , s = %.3f ' %s_LF4)
print('Case(d): Rotational loss at rated load , P_r = %.1f W' %P_rs_fl)
print(' Rotational loss at 1/4 load , P_r = %.1f W' %P_rs_LF1)
print(' Rotational loss at 1/2 load , P_r = %.2f W' %P_rs_LF2)
print(' Rotational loss at 3/4 load , P_r = %.1f W' %P_rs_LF3)
print(' Rotational loss at 5/4 load , P_r = %.1f W' %P_rs_LF4)
print('Case(e): Equivalent copper loss at rated load , P_cu = %.f W' %P_cu_fl)
print(' Equivalent copper loss at 1/4 load , P_cu = %.1f W' %P_cu_LF1)
print(' Equivalent copper loss at 1/2 load , P_cu = %.f W' %P_cu_LF2)
print(' Equivalent copper loss at 3/4 load , P_cu = %.1f W' %P_cu_LF3)
print(' Equivalent copper loss at 5/4 load , P_cu = %.1f W' %P_cu_LF4)
print('Case(f): Efficiency at rated load , η = %.1f W' %n_fl)
print(' Efficiency at 1/4 rated load , η = %.1f W' %n_LF1)
print(' Efficiency at 1/2 rated load , η = %.1f W' %n_LF2)
print(' Efficiency at 3/4 rated load , η = %.1f W' %n_LF3)
print(' Efficiency at 5/4 rated load , η = %.1f W' %n_LF4)
print('Case(g): Output horsepower at rated load , P_o = %.2f hp' %P_o)
print(' Output horsepower at 1/4 rated load , P_o = %.2f hp' %P_o_LF1)
print(' Output horsepower at 1/2 rated load , P_o = %.2f hp' %P_o_LF2)
print(' Output horsepower at 3/4 rated load , P_o = %.2f hp' %P_o_LF3)
print(' Output horsepower at 5/4 rated load , P_o = %.2f hp' %P_o_LF4)
print('Case(h): Output torque at full load , T_o = %.1f lb-ft' %T_o)
print(' Output torque at full load , T_oST = %.1f N-m' %T_o_ST)
print('\nNOTE: ERROR: Calculation error for efficiency at 3/4 load in textbook')
```