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Distribution Transformers

Supplier: AEM Cores
18 February, 2010

UNICORE adopted by Home UNICORE Technology Applications Distribution Transformers.

The majority of UNICOREs produced are used in power distribution applications. Typically distributed gap UNICOREs of various face geometries range from 25kg to 1000kg.

We have four different types of distributed gap cores for single phase applications, and three different types for three phase.

The accuracy and versatility of the Unicore machine enables a designer to fine tune the core dimensions to suit the application and minimise loss.

The benefits of improved performance must be balanced against the economics of construction, so the entire package cost including: raw material, heat treatment, transportation and assembly into the windings must be taken into consideration. It's a fact of life that an annealed core will have lower losses than an un-annealed core.

Because a Unicore is fully formed as it comes off the machine, it will hold it's shape without heat treatment. Any application where loss is critical will require an annealed core, especially in power distribution transformers.

Some Unicore users have modified their designs to allow them to use un-annealed Unicores for large transformers where the heat treatment costs become prohibitive. The designers have carefully evaluated the true loss of an un-annealed core and modified their core section to lower the flux density such that the loss is acceptable. Part of this re-design takes account of new construction techniques and other benefits possible with Unicores.

AEM Cores is continually testing core loss and evaluating the effect of assembly on all types of Unicores. As data becomes available it will be posted to this website under the page Performance Curves.

Core types particular to Power Distribution:

  • Distributed Gap (DGAP) and Diverging Distributed Gap (DDGAP) for single phase and 4 loop 5 limb three phase transformers.
  • DUO1 for single and three phase transformers.
  • DUO1 is particularly suitable for un-annealed cores as there is almost no 'destriction factor' when assembling.
  • End Overlap - ELAP and EOLAP for spiral wound, lamination overlapping, diverging distributed gap for single and three phase transformers.