If is a hypermap with bit set B, a voltage assignment on is simply a map z : B→Z, where Z is a group. If Z acts on a set X, and if z is a voltage assignment on , then one constructs a ‘ramified covering’ such that in the category of ramified coverings of , and are isomorphic whenever z and z′ are equivalent voltages (but not conversely). A lifting criterion is given for an automorphism of to lift to one of and applied to give a simple and conceptual proof of the hypermap version of Accola's theorem for hypermaps. Finally, cohomological aspects of these constructions are given in terms of Machi's homology theory for hypermaps.