In some circumstances such as with regard to contra-rotating turbo prop arrangements in aircraft it is desirable to vary the pitch of the blades and/or provide de-icing facilities. Advantageously, these blade pitch and de-icing facilities could be provided through electrical actuators. Unfortunately, provision of electrical power to such rotating components traditionally requires utilization of slip rings which are subject to wear. By providing a self-contained electrical generator including a first hub and second hub with respective generator parts it is possible to utilize the contra-rotating nature in order to create relative motion and therefore electrical power generation in coils opposed by permanent magnets. Slide contacts for electrical connection are avoided whilst electrical power can be generated within the rotating reference frame defined by the hubs.