An alternator running at 500r/min supplies a load at 50Hz. Determine the poles the alternator have.
The number of poles of an alternator can be determined using the formula:
\text{Number of poles} = \frac{120 \times \text{frequency}}{\text{rotational speed}}
Given that the frequency is 50Hz and the rotational speed is 500r/min, we can substitute these values into the formula:
\text{Number of poles} = \frac{120 \times 50}{500}
\text{Number of poles} = \frac{6000}{500}
\text{Number of poles} = 12
Therefore, the alternator has 12 poles.