In [1]:

```
#pg 329
#calculate the emf generated
# Given data
A = 2.;# in wavewound
N = 1200.;# in rpm
phi = 0.02;# in Wb
n = 65.;# no of slots
P = 4.;
#calculations
Z = n*12;# total number of conductor
# Emf equation
Eg = (N*P*phi*Z)/(60*A);# in V
#results
print "The emf generated in V is",Eg
```

In [2]:

```
#pg 329
#calculate the number of conductors
# Given data
P = 8.;
N = 1200.;# in rpm
phi = 25.;# in mWb
phi = phi * 10**-3;# in Wb
Eg = 440.;# in V
A = P;
#calculations
# Eg = (N*P*phi*Z)/(60*A);
Z = (Eg*60*A)/(phi*N*P);# in conductors
print "The numbers of conductors when armature is lap wound",Z
A = 2;
# Eg = (N*P*phi*Z)/(60*A);
Z = (Eg*60*A)/(phi*N*P);# in conductors
print "The numbers of conductors when armature is wave wound ",Z
```

In [3]:

```
#pg 330
#calculate the induced voltage
# Given data
P = 4;
phi = 20;# in mWb
phi = phi * 10**-3;# in Wb
A = 4;
P = A;
N =720.;# in rpm
n = 144.;# no of slots in slots
n1 = 2.;# no of coils
n2 = 2;# no of turns in turns
#calculations
Z = n*n1*n2;# total number of conductor
# Generated emf
E = (N*P*phi*Z)/(60*A);# in V
#results
print "The induced voltage in V is",E
```

In [4]:

```
#pg 330
#calculate the emf
# Given data
Eg1 = 100.;# in V
phi1 = 20.;# in mWb
phi1 = phi1 * 10**-3;# in Wb
N1 = 800.;# in rpm
N2 = 1000.;# in rpm
#calculations
# Eg1/Eg2 = (phi1/phi2) * (N1/N2) but phi1 = phi2
Eg2 = (Eg1*N2)/N1;# in V
print "Part (i) : The generated emf in V is",Eg2
phi2 = 24;# in mWb
phi2 = phi2 * 10**-3;# in Wb
N2 = 900;# in rpm
# Eg1/Eg2 = (phi1/phi2) * (N1/N2) ;
Eg2 = (Eg1*N2*phi2)/(N1*phi1);# in V
print "Part (ii) : The generated emf in V is",Eg2
```

In [5]:

```
#pg 331
#calculate the power
# Given data
P = 30;# in kW
P = P * 10**3;# in W
V = 300.;# in V
Ra = 0.05;# in ohm
Rsh = 100;# in ohm
#calculations
# p = V*I_L;
I_L = P/V;# in A
Ish = V/Rsh;# in A
Ia = I_L+Ish;# in A
Eg = V + (Ia*Ra);# in V
# power developed by armature
power = (Eg*Ia);# in W
power = power * 10**-3;# in kW
#results
print "The total power developed by the armature in kW is",round(power,2)
```

In [6]:

```
#pg 331
#calculate the power
# Given data
V = 200;# in V
Ra = 0.5;# in ohm
Rsh = 200;# in ohm
P = 20;# in kW
P = P * 10**3;# in W
#calculations
# P = V*I_L;
I_L =P/V;# in A
Ish = V/Rsh;# in A
Ia = I_L+Ish;# in A
Eg = V + (Ia*Ra);# in V
# power developed in the armature
power = Eg*Ia;# in W
power = power * 10**-3;# in kW
#results
print "The power developed in the armature in kW is",round(power,1)
```

In [7]:

```
#pg 332
#calculate the armature current and emf
# Given data
P = 60.;
A =P;
Vbrush = 2;# in V/brush
Vt = 100.;# in V
Ra = 0.1;# in ohm
Rsh = 80;# in ohm
#calculations
Ish = Vt/Rsh;# in A
Ilamp = P/Vt;# in A
I_L = 50*Ilamp;# in A
# Armature current
Ia = I_L+Ish;# in A
# Evaluation of generated emf
Eg = Vt + (Ia*Ra) + Vbrush;# in V
#results
print "The total armature current in A is",Ia
print "The generated emf in V is",Eg
```

In [8]:

```
#pg 332
#calculate the generated voltage
# Given data
V = 440.;# in V
I_L =40.;# in A
Rse = 1.;# in ohm
Rsh = 200.;# in ohm
Ra = 0.5;# in ohm
#calculations
Ish = V/Rsh;# in A
Ia = I_L+Ish;# in A
Eg = V + (Ia*(Ra+Rse));# in V
print "The generated voltage for long shunt in V is",Eg
#Voltage across shunt field, Vsh = V + Ise*Rse = V + (I_L*Rse);
Vsh = V+(I_L*Rse);# in V
Ish = Vsh/Rsh;# in A
Ia =I_L+Ish;# in A
Eg = V + (I_L*Rse) + (Ia*Ra);# in V
print "The generated voltage for short shunt in V is",Eg
```

In [9]:

```
#pg 341
#calculate the back emf
# Given data
V = 440.;# in V
I = 80.;# in A
Rse = 0.025;# in ohm
Ra = 0.1;# in ohm
Bd = 2.;# brush drop in V
#calculations
Ia = I;# in A
Ise = I;# in A
Eb = V - (Ia*(Ra+Rse)) - Bd;# in V
#results
print "The back emf in V is",Eb
```

In [10]:

```
#pg 341
#calculate the armature current and back emf
# Given data
V = 250.;# in V
I_L = 20;# in A
Ra = 0.3;# in ohm
Rsh = 200;# in ohm
#calculations
Ish = V/Rsh;# in A
# I_L = Ia+Ish;
Ia = I_L-Ish;# inA
Eb = V-(Ia*Ra);# in V
#results
print "The armature current in A is",Ia
print "The back emf in V is",Eb
```

In [11]:

```
#pg 342
#calculate the speed in rpm
# Given data
P = 4.;
A = 2.;#(wave connected)
Z = 200.;
V=250.;# in V
phi = 25.;# in mWb
phi = phi * 10**-3;# in Wb
Ia = 60;# in A
I_L = 60;# in A
Ra = 0.15;# in ohm
Rse = 0.2;# in ohm
#calculations
#V = Eb + (Ia*Ra) + (Ia*Rse);
Eb = V - (Ia*Ra) - (Ia*Rse);# in V
# Eb = (phi*P*N*Z)/(60*A);
N = (Eb*60*A)/(phi*P*Z);# in rpm
#results
print "The speed in rpm is",N
```

In [12]:

```
#pg 343
#calculate the resistance and current
# Given data
Eb = 227.;# in V
Rsh = 160.;# in ohm
Ish = 1.5;# in A
I_L = 39.5;# in A
#calculations
V = Ish*Rsh;# in V
Ia = I_L-Ish;# in A
#V = Eb + (Ia*Ra);
Ra = (V-Eb)/Ia;# in ohm
Ia = V/Ra;# in A
#results
print "The armature resistance in ohm is",round(Ra,3)
print "The armature current in A is",round(Ia,1)
```

In [13]:

```
#pg 343
#calculate the ratio of speed
# Given data
V = 230;# in V
Ra = 0.115;# in ohm
Rsh = 115.;# in ohm
I_L = 100.;# inA
#calculations
Ish =V/Rsh;# in A
Ia = I_L + Ish;# in A
Eg = V + (Ia*Ra);# in V
Ia = I_L-Ish;# in A
Eb = V - (Ia*Ra);# in V
# The ratio of speed as a generator to speed as a motor
NgBYNm = Eg/Eb;
#results
print "The ratio of speed as a generator to speed as a motor is",round(NgBYNm,3)
```

In [14]:

```
#pg 344
#calculate the induced voltage
# Given data
P = 4;
slots = 144.;
phi = 20.;# in mWb
phi = phi * 10**-3;# in Wb
N = 720.;# in rpm
A = 4.;
P =4.;
n1 = 2;# in coil/slot
n2 = 2;# in turns/coil
#calculations
Z = slots*n1*n2;# total number of conductor
Eg = (N*P*phi*Z)/(60*A);# in V
#results
print "The induced voltage in V is",Eg
```

In [15]:

```
#pg 344
#calculate the emf
# Given data
P = 8;
phi = 0.1;# in Wb
Z = 400.;
N =300.;# in rpm
#calculations
Eg = (N*phi*Z)/(60);# in V (A = p)
print "The emf when lap is connected in V is",Eg
# For A=2, connected armature
A = 2;
Eg = (N*phi*P*Z)/(60*A);# in V
print "The emf when wave is connected in V is",Eg
```

In [16]:

```
#pg 345
#calculate the power
# Given data
P_L = 20;# in kW
P_L = P_L * 10**3;# in W
V = 200;# in V
Ra = 0.05;# in ohm
Rsh = 200.;# in ohm
#calculations
# P_L = V*I_L;
I_L = P_L/V;# in A
Ish = V/Rsh;# in A
Ia = I_L+Ish;# in A
Eg = V + (Ia*Ra);# in V
Pa = Eg*Ia;# in W
Pa = Pa * 10**-3;# in kW
#results
print "The power developed in armature in kW is",round(Pa,1)
```

In [17]:

```
#pg 345
#calculate the speed
# Given data
N1 = 600.;# inrpm
I_L1 = 60.;# in A
V = 230.;# in V
Rsh = 115.;# in ohm
Ra= 0.2;# in ohm
Ia2 = 30.;# in A
#calculations
Ish = V/Rsh;# in A
Ia1 = I_L1 - Ish;# in A
Eb1 = V-(Ia1*Ra);# in V
Eb2 = V - (Ia2*Ra);# in V
# N1/N2 = Eb1/Eb2;
N2 = (N1*Eb2)/Eb1;# in rpm
#results
print "The speed when 30 A current through the armature in rpm is",round(N2,2)
```

In [18]:

```
#pg 346
#calculate the speed of motor
# Given data
P = 6;
A = 6.;
Z = 500.;
Ra = 0.05;# in ohm
Rsh =25.;# in ohm
V = 100.;# in V
I_L = 120.;# in A
phi = 2*10**-2;# in Wb
#calculations
Ish = V/Rsh;# in A
Ia = I_L-Ish;# in A
Eb = V - (Ia*Ra);# in V
# Eb = (N*P*phi*Z)/(60*A);
N = (Eb*60*A)/(P*phi*Z);# in rpm
#results
print "The speed of the motor in rpm is",N
```

In [19]:

```
#pg 346
#calculate the change in emf
# Given ata
N1 = 1;
N2 = 1.2*N1;
phi1 = 1;
phi2 = 0.8*phi1;
Eg1BYEg2 = (N1/N2) * (phi1/phi2);
Eg1 = 1;# assumed
# The change in emf
#calculations
Eg2 = (Eg1*phi2*N2)/(phi1*N1);
Eg2 = Eg2 * 100;# in %
#results
print "The change in emf in percent is",Eg2
```

In [21]:

```
#pg 347
#calculate the armature power
# Given data
Pout = 25.;# in kW
Pout = Pout*10**3;# in W
Vt = 250.;# in V
Ra = 0.06;# in ohm
Rsh = 100.;# in ohm
#calculations
# Pout = Vt*I_L;
I_L = Pout/Vt;# in A
Ish = Vt/Rsh;# in A
Ia = I_L+Ish;# in A
Eg = Vt + (Ia*Ra);# in V
# Total armature power developed when working as a generator
Pdeveloped = Eg*Ia;# in W
Pdeveloped = Pdeveloped * 10**-3;# in kW
print "Total armature power developed in kW is",round(Pdeveloped,3)
Ia = I_L-Ish;# in A
Eb = Vt - (Ia*Ra);# in V
# Total armature power developed when working as a motor
Pdeveloped = Eb*Ia;# in W
Pdeveloped = Pdeveloped * 10**-3;# in kW
print "Total armature power developed when working as a motor in kW is",round(Pdeveloped,4)
```

In [22]:

```
#pg 347
#calculate the useful flux
# Given data
P = 4.;
A = 4.;
Turns = 100.;
N = 600.;# in rpm
Eg = 220.;# in V
n = 2.;# no of total conductors
Z = n*Turns;
#calculations
# Eg = (N*P*phi*Z)/(60*A);
phi = (Eg*60*A)/(N*P*Z);# in Wb
print "The useful flux per mole when armature is LAP connected in Wb is",phi
A = 2;
# Eg = (N*P*phi*Z)/(60*A);
phi = (Eg*60*A)/(N*P*Z);# in Wb
print "The useful flux per mole when armature is WAVE connected in Wb is",phi
```