Actually; It's not really a stepdown transformer, it has a middle point on=
the primary in the transformer to drive 110v equipment! Like the drives an=
The terminology may vary across the Pond, but over here that would be
called a 'step down autotransformer'. An autotransformer is one with a
signle winding, suitably tapped, and thus provides no isolation between
input and output.
-tony