Development of condition monitoring techniques for a transverse flux motor

Advances in electrical machine design have enabled Rolls-Royce to develop a novel 20 MW machine for marine propulsion. This machine is named a transverse flux motor (TFM) because of the three-dimensional flux paths created within it. The TFM will potentially provide propulsion power to a fleet of future Royal Navy vessels as part of the UK MoD drive towards the All Electric Ship (AES) concept. To minimise through life costs (TLC) whilst maintaining 100 % availability during the vessels operating lifetime, part of the TFM program includes development of an integrated condition-based monitoring system. The development and testing of such a condition-based monitoring system was also identified as a potential source of valuable information during TFM design. This paper provides an outline of the novel machine configuration, discusses the identification of possible failure modes, the symptoms exhibited by these and the information content that different measurement parameters potentially yield. In particular, this paper focuses on the development of condition based maintenance (CBM) by the monitoring of magnetic flux within the machine. A theoretical analysis of the flux paths is provided and then some real results from testing of prototype TFM machines are illustrated. The relevance of monitoring in the ways described is then discussed (in relation to manufacturers and end users of more conventional machines). In addition, the role that the outlined work has to play in the monitoring of complete systems is summarised. This is of particular importance given that the maintenance function is more recently being driven by a business-centred approach and is seen as key to operation of the whole plant, not simply individual equipment.