3 phase transformers are used in most electrical power systems for power generation, distribution, and transmission. These are used to step-up (increase) or step-down (decrease) the voltages in the three-phase systems. There are different 3 phase transformer manufacturers in the market today who ensure that the transformers built by them are more economical for large power distribution. They even supply custom auto transformers based on your requirements.

Let’s look at some of the advantages and disadvantages of a 3 Phase Transformer:

Pro of 3 Phase Transformers over Single Phase Transformers

There are numerous advantages of using a 3-phase transformer over a single phase transformer, some of which have been listed below:

Inexpensive: Compared to a Single-Phase transformer the 3 phase transformer comes at a cheaper price. It has a low cost when compared with the three units of single-phase transformers.

Lightweight: Not only is the transformer lightweight, it is also smaller than the single-phase transformer in size which means that it also occupies less space.

Assembly in least time: It is extremely easy to assemble. We can get a single phase supply from a 3-phase transformer, while the opposite is not possible.

Higher efficiency: The 3-phase transformer performs its functions more efficiently and delivers more power than the single-phase transformer.

Easier to install: The 3-phase transformers are pre-wired and ready to install; thus makes the installation process very easy and smooth.

Easy transportation: In order to provide the same output, the material used for building the core of the transformer is very little as compared to a bank of three single phase transformers. Not only is transportation easy but also reduces transportation cost.

Although they have many advantages over their single-phase counterparts, they don’t come without their disadvantages.

Greater cost of standby units: The individual cost of the standby units is high and makes it difficult to repair or fix any malfunctions. In a 3-phase transformer

, a common core is shared by all three units. Therefore if the unit is defective or is damaged, the entire three-phase transformer has to be shut down.

Cost of repair: The cost to repair a 3-phase transformer is higher since changing each individual component is expensive. Hence, to restore the service, the spare unit cost is more when compared to a single-phase transformer.

Reduced capacity: Since the 3-phase transformers are self-cooled, the capacity of the transformer is also reduced simultaneously.

Fault correction: In case there is a fault in any of the phases of the 3 phase transformers, the fault is transferred to the other two phases. As a result, the whole unit needs replacement.


Although most utility tools are connected by the single-phase transformers, these are not preferred for large power distribution. In comparison to the single phase transformer, the 3-phase transformer has numerous advantages. There are a few disadvantages as well but the advantages definitely outweigh them. This is the reason why 3-phase transformers are now being used for large power distribution.

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