Can single phase transformers be used on a three phase source?

A transformer can’t act as a phase changing device and change single-phase into 3-phase or 3-phase into single phase. So a question frequently asked is: Can a single-phase transformer be used on a three phase source? The answer is YES! 
 
We all pretty much know that transformers are constructed as either singe phase or three phase. Voltage transformers, however, can be constructed for connection to not only one-phase or three-phase but for two-phases, six-phases and even elaborate combinations up to 24-phases for some DC rectification transformers. If we take 3 single-phase  transformers and connect their primary windings to each other and their secondary windings to each other in a fixed configuration (either delta or wye), we can use the transformers on a three-phase supply. 
 
To make the transformer connections compatible with three-phase supplies we need to connect 3 single-phase transformers together in a particular way to form one Three Phase Transformer. 
 
A three phase transformer or 3φ transformer can be constructed either by connecting together 3 single-phase transformers, thereby forming a so-called three phase transformer bank or by using one pre-assembled and balanced three phase transformer which consists of three windings mounted onto one laminated core. 
 
The advantages of building a single three phase transformer is that for the same kVA rating it will be smaller, cheaper and lighter than three individual single phase transformers connected together because the copper and iron core are used more effectively. The methods of connecting the primary and secondary windings are the same, whether using just one Three Phase Transformer or three separate Single Phase Transformers.