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What does the letters "FCBN" and "FCAN" refer to in regard to the taps of a Low Voltage dry type Distribution Transformer?

Tap designation on Transformers

Product Line:
LV Transformers

Applies to Low Voltage Transformers by SquareD/Schneider Electric

Low Voltage Transformers often have adjustable taps to compensate for varying incoming voltages


These refer to the fact that the taps are designed to carry the full capacity of the Transformer at voltages above or below the nameplated nominal input voltage.

FCAN stands for ``Full Capacity Above Nominal``
FCBN stands for ``Full Capacity Below Nominal``

For example: If a Transformer has 2 - 5% FCBN taps and the nominal voltage is 240 volts, then there are two taps below 240 volts in 5% increments. 5% of 240 is 12 volts, thus there is are taps for 228 and 216 volts. Since kVA capacity is voltage times current (for single phase; for three phase also multiply by 1.732 (the square root of 3),) the fact that the tap can handle the full capacity of the transformer in kVA, means that the tap can handle enough current for the Transformer to provide the nameplate kVA rating with that voltage input.
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