Advantages of three phase transformer :-



1) 3 phase transformer is weight less and occupied less space.
2) Cost of 3 phase transformer is less than three single phase transformer.
3) Only one unit is require to handle makes it easy for operator.
4) Easy Transportation.
5) More efficient.
6) Small core with less material require.
7) Simpler installation.
8) In three phase transformer terminals brought out are only 3.
9) Insulation is simpler in three phase transformer than 3 single phase transformer.

Disadvantages of three phase transformer: 


1) If one of the phase winding of 3 phase transformer is became difective the entire transformer must be taken out for repair works and thereby completely disturbing power supply.
 But bank of 3 single phase transformer offer the advantage of open Delta with reduce rating with one of the unit is in operate.