Difference between autotransformers for voltage change and autotransformers to generate artificial neutral

Three-Phase Autotransformer for voltage change

Models: AUTW (IP23) – AUTX (IP00) – AUTZ (IP65)

Power from 1 KVA to 1000KVA

Voltages: 400V/230V with neutral.

Connection: Yn0

These autotransformers are used for voltage changes, to feed three-phase electrical machines or balanced loads, with imbalances not greater than 10%.

They can be used for 400V connection inputs and power machines or leads whose inputs is 230V. Or the other way around for old three-phase lines at 230V and powering machines at 400V.

They are reversible meaning thar we can enter by 400V or by 230V.

The neutral is common and can be used for both input and output. In case of voltage imbalances, it is recommended not to connect the input neutral to the connection.

The autotranformers are not separators therefore, if an isolated neutral and a galvanic separation from the connection are required, the use of separating transformers is recommended, models:

TTDW – X – Z : 400/230 Yyn0

TTUW – X – Z : 230/400 dYN11

Installation examples:

Diferencia entre autotransformadores para cambio de tensión y autotransformadores para generar neutro artificial

Three-phase Autotransformer artificial neutral generators

Models: AUTNW (IP23) – AUTNX (IP00) – AUTNZ (IP65)

Power from 1 KVA to 400KVA

Voltages: 400V+NEUTRAL.

Connection: Zn0

These autotransformers are not used to change voltage. They are to generate a neutral in the installation, when it is required and is not available in the print run that reaches the machine to be fed. Sometimes, due to distance, it is uneconomical to pull the neutral cable and this is the solution for this problem.

The ZN0 connection guarantees a higher impedance to the autotransformer, so it will be better withstand any unbalances that may exist in the load.