Three-phase or 3-phase supplies are used for electrical power generation, transmission and distribution. They have many advantages over single-phase supply and thus, are highly used in industries. 3-phase transformers have to deal with three alternating currents and voltages. A transformer cannot change single-phase to 3-phase or vice-versa. To make the transformer connections compatible with 3-phase supplies, they need to be connected in a particular pattern to form a 3-phase transformer configuration. In a 3-phase transformer, three primary windings of three single-phase transformers are connected to one another and three secondary windings are inter-connected in a fixed configuration to get a 3-phase supply.
The sets of primary and secondary windings in three phase transformers are connected in either Δ or Y configurations to form a complete unit. The winding options may be Y – Y or Y – Δ or Δ – Y or Δ – Δ. The reason for choosing a Δ or Y configuration for transformer winding connections is that Δ connections enjoy a higher level of reliability and Y connections can provide chances for multiple voltages. (In a Δ configuration, if one winding fails open, the other two can still maintain full line voltages to the load, thus higher reliability).
3-phase transformers can also be built by mounting three pairs of single-phase windings onto a single laminated core. However, a single 3-phase transformer is much better than three individual single-phase transformers connected together because the copper and iron cores are used more effectively, resulting in a smaller, lighter and much inexpensive transformer for the same kVA rating. Whatever kind of transformer, it is very essential that the connections made are perfect because wrong connections will damage the equipment and cause injuries too. You can rely on Miracle Electronics to provide you with the best-in-quality three phase transformers that are efficient and fault-free. The high performance transformers are built on high quality benchmarks that are in accordance with International standards, due to which they are used across numerous industries across the globe effectively, making Miracle Electronics the best transformer manufacturer in India.
Let us now have a look at the several supply combinations you can have for single-phase or 3-phase powers when you connect transformers.
- Single-phase power – single voltage: This includes one hot conductor and one grounded conductor; or two hot conductors, where both the conductors can be connected for single voltage.
- Single-phase power – dual voltage: This include two hot conductors and one grounded neutral conductor, where two hot conductors are connected for full voltage; and one hot conductor and the grounded neutral conductor are connected for lower voltage.
- 3-phase power – single voltage: This includes three hot conductors that are connected for 3-phase voltage; and any pair can be connected for single-phase voltage.
- 3-phase power – dual voltage: This includes three hot conductors and a grounded neutral conductor, where all three hot conductors are connected for 3-phase power; and any two hot conductors are connected with the grounded neutral conductor for single-phase voltage.