Transformers larger than 50 kVA with two coils are constructed with how many secondary terminals?

Transformers larger than 50 kVA that have two coils are typically constructed with four secondary terminals. This configuration allows for greater flexibility in connecting different loads and tapping into various voltage requirements. By using four terminals, the secondary winding can be arranged in such a way as to facilitate both series and parallel connections, depending on the electrical demands of the system.

In many cases, this setup also accommodates multiple voltage output options or enables the transformer to be configured for different transforming ratios, which enhances its versatility in applications where load variety may be significant. Each terminal provides access points for distinct configurations that can adapt to various service conditions, which is essential in industrial settings and complex electrical grids.

Other options, such as having two, three, or five secondary terminals, would not generally align with the standard design practices for transformers of this size and type, as they either limit the flexibility in load connections or do not meet the operational requirements typically expected from larger transformers.