The problem given in the image describes a 6-pole generator with wave winding, and you are asked to calculate the generated electromotive force (emf) based on certain conditions.

Problem Breakdown:

1. Given Data:

   • Number of poles $P = 6$
   • Number of conductors $Z = 664$
   • Flux per pole $\phi_1 = 60 \, \text{mWb} = 60 \times 10^{-3} \, \text{Wb}$
   • Speed $N_1 = 250 \, \text{rpm}$
   • Required emf for second condition $E_2 = 550 \, \text{V}$
   • Reduced flux per pole for second condition $\phi_2 = 58 \, \text{mWb} = 58 \times 10^{-3} \, \text{Wb}$

2. First Calculation:

   • We need to calculate the generated emf $E_1$ when the flux is $\phi_1 = 60 \, \text{mWb}$ and the speed is $N_1 = 250 \, \text{rpm}$.

   The formula for the generated emf in a generator with wave winding is:

   $E = \frac{P \times \phi \times Z \times N}{60 \times A}$

   Where:

   • $P$ is the number of poles.
   • $\phi$ is the flux per pole (in Wb).
   • $Z$ is the total number of conductors.
   • $N$ is the speed in rpm.
   • $A$ is the number of parallel paths in the armature (For wave winding, $A = 2$).

3. Second Calculation:

   • Find the speed $N_2$ required to generate an emf of $E_2 = 550 \, \text{V}$ with a reduced flux $\phi_2 = 58 \, \text{mWb}$.

   Using the same formula, we will rearrange it to solve for the required speed.

Let me calculate both steps for you.### Results:

1. The generated emf $E_1$ when the flux is 60 mWb and the speed is 250 rpm is 498 V.
2. The speed $N_2$ required to generate an emf of 550 V when the flux is reduced to 58 mWb is approximately 285.63 rpm.

Would you like more details or clarifications on any step?

Here are five related questions to expand on this topic:

1. How does changing the number of poles affect the generated emf?
2. What is the significance of wave winding in generators?
3. How would the generated emf change if the armature winding had lap winding instead of wave winding?
4. Can we calculate the power output of the generator from the given emf and flux values?
5. What factors affect the efficiency of a generator besides speed and flux?

Tip:

The relationship between emf, flux, and speed is direct, meaning small changes in flux or speed can significantly impact the generated voltage.