On the basis of number of phases transformers can be categorized either as single phase or three. A single-phase transformer comprises of a single-phase primary and a single-phase secondary placed with either core or shell-type construction. On the other hand three phase transformer has three-phase primary and three-phase secondary that is placed with either core or shell-type construction.
The three-phase transformer can be constructed by connecting three single-phase transformers into a three-phase transformer bank.
|Feature/Type||Three-phase transformer||Three-phase transformer bank|
|Basic Construction||It comprises a common magnetic circuit for all three phases||Made by connecting three single-phase transformers|
|Number of magnetic circuits||It comprises of a common magnetic circuit for all three phases||It has separate magnetic circuits|
|Operations and Maintenance||Easy||Difficult|
|Units||Single unit||Multiple units|
|Faults and clearance||Difficult to clean, as it is a single unit||Easier to clean, as any single unit in which fault has occurred can be replaced|
|Type of connections (Star or Delta)||Can be connected in bothconfigurations||Can be connected in both configurations|