___-connected primaries are more common.

___-connected primaries are more common.

• A. Wye
• B. Delta
• C. Star
• D. Hybrid

Answer: (B)

Delta-connected primaries are most common because the primary side of many 3-phase power systems is a three-wire, neutral-free delta. In this setup each winding handles the line-to-line voltage directly, which suits standard high-voltage windings and simplifies switching and protection without needing a neutral on the primary. A delta primary also pairs well with a secondary that provides a neutral (often a wye-connected secondary with a grounded neutral) to supply line-to-neutral loads. In contrast, a star (wye) primary requires a neutral point on the source side, which isn’t always available or desirable, making delta the typical choice for primary connections in common transformer configurations. Hybrid is not a standard, widely used primary arrangement.

Delta-connected primaries are most common because the primary side of many 3-phase power systems is a three-wire, neutral-free delta. In this setup each winding handles the line-to-line voltage directly, which suits standard high-voltage windings and simplifies switching and protection without needing a neutral on the primary. A delta primary also pairs well with a secondary that provides a neutral (often a wye-connected secondary with a grounded neutral) to supply line-to-neutral loads. In contrast, a star (wye) primary requires a neutral point on the source side, which isn’t always available or desirable, making delta the typical choice for primary connections in common transformer configurations. Hybrid is not a standard, widely used primary arrangement.