Provision of Electrical Power throughout the Stack of the Nuclear Structure Facility Tandem at Daresbury Laboratory

The provision of electrical power to supply magnets, beam optical elements, and vacuum pumps distributed throughout the stack of the NSF 30 MV tandem is not trivial because of the very high potentials at which these components are located and the high power demanded. The most practical way to solve this problem is to transfer power mechanically, generating the electrical power by means of alternators at the positions required. The mechanical system developed and described in this paper consists of an insulating power shaft arrangement capable of transmitting up to 60 kW rotating at 1500 rpm. The general development of the system is described from its early origin, some three years ago, to the final design to be used on the NSF tandem. Three main topics are discussed: the research and development carried out on the electrical and mechanical properties of suitable materials, the detailed design analysis conducted, and the prototype and model tests concluded to verify the performance and reliability of the design.