
90 7 ◊ Transformers and Reactors
The interphase transformer design should also be considered. Fig-
ure 7.13 shows two-leg and three-leg core constructions for an inter-
phase transformer. The two-leg design has no magnetomotive force
(MMF) balance and will spew a large amount of leakage flux that has
the potential for heating the floor or walls of a cabinet. It is sometimes
used because it requires less iron than a three-leg core design. The
three-leg design has cancelling fluxes from the conductors and has a
minimum leakage flux. The small cost difference is good insurance
against field problems.
7.7. Transformer Connections
Autotransformer connections are ...