Which invention allowed efficient long-distance transmission of alternating current?

Which invention allowed efficient long-distance transmission of alternating current?

• A. Transformer for DC
• B. Three-phase generator by Dolivo-Dobrovolsky
• C. Incandescent tungsten bulb
• D. DC motor

Answer: (B)

The idea being tested is how using multiple phases in AC generation enables efficient long-distance power delivery. A three-phase system provides a smooth, nearly continuous flow of electrical power, reducing pulsations and improving the efficiency and stability of transmission and distribution. It works especially well with transformers, which step voltage up for long-distance runs and step it down for local use, allowing power to travel farther with lower losses and still deliver steady voltage at the end user. Dolivo-Dobrovolsky’s work on a practical three-phase generator (and the accompanying three-phase transformer) gave engineers a workable, scalable way to generate, transmit, and distribute large amounts of AC power. This made long-distance transmission more economical and reliable than single-phase approaches, because the three-phase system provides better efficiency, balance, and compatibility with transformer-based voltage changes. If you think about the other options: a DC transformer isn’t practical because transformers rely on changing magnetic flux, which DC does not provide; the incandescent tungsten bulb and the DC motor are unrelated to enabling efficient long-distance AC transmission.

The idea being tested is how using multiple phases in AC generation enables efficient long-distance power delivery. A three-phase system provides a smooth, nearly continuous flow of electrical power, reducing pulsations and improving the efficiency and stability of transmission and distribution. It works especially well with transformers, which step voltage up for long-distance runs and step it down for local use, allowing power to travel farther with lower losses and still deliver steady voltage at the end user.

Dolivo-Dobrovolsky’s work on a practical three-phase generator (and the accompanying three-phase transformer) gave engineers a workable, scalable way to generate, transmit, and distribute large amounts of AC power. This made long-distance transmission more economical and reliable than single-phase approaches, because the three-phase system provides better efficiency, balance, and compatibility with transformer-based voltage changes.

If you think about the other options: a DC transformer isn’t practical because transformers rely on changing magnetic flux, which DC does not provide; the incandescent tungsten bulb and the DC motor are unrelated to enabling efficient long-distance AC transmission.