The use of multiple windings (pole pairs) in each phase primarily enables what outcome?

• A. To increase the generator's voltage without changing speed
• B. To reduce mechanical complexity
• C. To reduce the need for cooling
• D. To allow slower rotation while maintaining the same electrical frequency

Answer: (D)

The essential idea is how the number of magnetic poles in a generator links speed and electrical frequency. The frequency f is determined by the product of pole count P and rotational speed N, roughly f = (P × N) / 120. So, for a fixed frequency, increasing the number of poles lets the machine run slower. Using multiple windings in each phase to create more pole pairs increases P, enabling slower rotation while keeping the same electrical frequency. That’s why this design choice is about matching speed to the required frequency, not about boosting voltage at a given speed or reducing cooling or mechanical complexity.