Leakage Transformer

Leakage transformers are designed to have reduced coupling between the input and output circuit windings and increased leakage field, which is normally undesirable on fixed-coupled transformers. Operating curves with high open-circuit voltages and defined current-voltage values at load can be realised.

Leakage transformers can also be designed as absolutely short-circuit-proof transformers for higher power ratings, but they represent a very complex special design.

Note:
Typical applications for leakage transformers are gas discharge lighting (“neon lights”) with high ignition voltages and subsequent limitation of the current in the gas path which now represents a “short circuit”.

For some converter circuits, transformers with increased short-circuit voltages are required, which, depending on the level of the short-circuit voltage, can also already be referred to as leakage transformers.
By combining an AC choke and a fixed-coupled transformer, circuit characteristics comparable to a leakage transformer can be produced.

Because of the complex engineering work involved, leakage transformers are commercially unfavourable for single units and very small series.