A turns index for pulse transformer design

FOR a good many years designers of power transformers and distribution transformers have had a guide number to use in starting their first design.1, 2 This is expressed by the equation Vt = K√kva where Vt is the volts per turn to use in starting the first design; K is a constant which may vary between relatively narrow limits; and kva is the kilovolt-ampere rating of the transformer. In practice, the constant K is about 1.25 for shell-type power transformers, about 0.6 for core-type power transformers, and about 0.4 for core-type distribution transformers.