an adaptor is disclosed for connecting a generator to a prime mover . the adaptor comprises two separable parts . by providing an adaptor comprising two separable parts , it may be possible for one part to be removed in order to allow access to moving parts which would otherwise be inaccessible . this may simplify the process of servicing moving parts such as a coupling or bearings , without requiring the generator and the prime mover to be moved apart . a coupling with a radially removable elastomeric component is also disclosed .