From Table 14-1, choose a 9-kVA, 3-phase, 240-V-to-
480-V step-up transformer.
Three single-phase transformers can be used to supply
a 3-phase load. This is frequently the case when low
kVA rating are required, such as in Problem 14-6. When
single-phase transformers are used, the rating of each
transformer must be not smaller than one-third the 3-
phase kVA required. In Problem 14-6, the 3-phase load
requirement is 8.3 kVA. Therefore, the single-phase
transformer rating must be at least 2. 8 k VA.