  Conformastationary metrics have been derived by Perjes and by Israel and
Wilson as source-free solutions of the Einstein-Maxwell equations. By analogy
with the conformastatic metrics which have charged dust sources it was assumed
that conformastationary metrics would be the external metrics of charged dust
in steady motion. However for axially symmetric conformastationary metrics we
show that, as well as moving dust, hoop tensions are always necessary to
balance the centrifugal forces induced by the motion. Exact examples of
conformastationary metrics with disk sources are worked out in full.
Generalisations to non-axially symmetric conformastationary metrics are
indicated.
