When should a three-phase to single-phase transformer be used?

As a general rule, on an industrial level, we find three-phase installations made up of 3PH+N, thus being able to supply both single-phase loads and three-phase loads.

However, there are cases where the single-phase load to be supplied is of considerable rating and we cannot supply it only between the phase and neutral, or we want to unbalance the network we are supplying from as little as possible.

For these situations, we have three-phase to single-phase isolation transformers, these devices used to convert the electrical energy from a three-phase system to a single-phase system in an efficient and economical way, thus being able to go from 3 phases of 400V to 2 phases of 230V.

How do we know if we can use a three-phase to single-phase transformer?

With this type of transformer, a total balance of the primary currents is not achieved, due to the fact that the central phase returns the intensity of the other 2 phases, so it will be twice as loaded. In practical terms, in order to know if we can use this type of transformer, the network from which we are supplied should have at least double the capacity of the power of the three-phase to single-phase transformer to be connected.

In order to provide a solution to these situations, POLYLUX has our standardised TTK series, consisting of isolation transformers that convert 400V three-phase voltage into 230V single-phase voltage, in V/ inverted V format.

Applications where to install a three-phase to single-phase transformer

Its use has become increasingly common in industrial and commercial applications where a single-phase rating supply is required from a three-phase rating source.

Our TTK transformers can be used for:

Galvanic isolation of electrical installations for safety reasons.
Achieving a better balance of primary currents than connecting only one phase and neutral of a three-phase line.
Connecting a single load of up to half the mains rating.
Installations where many single-phase loads have to be connected to the same line, the three-phase transformer can also help to provide more rating on that line.