TRANSFORMER RATINGS
Transformers are rated in volt-amperes (VA) or kilo volt-amperes
(k VA). This means that the primary and the
secondary winding are designed to withstand the VA or
k VA rating stamped on the transformer nameplate. The
primary and secondary full-load currents usually are not
given. The installer must be able to calculate the primary
and secondary currents from the nameplate information.
When the volt-ampere (or kilo volt-ampere) rating is
given, along with the primary voltage, then the primary
full-load current can be determined, using Equation 14.4
(for a single-phase transformer) or Equation 14.5 (for a
3-phase transformer).
Single phase: