ABSTRACT
The paper is based on concrete solutions experienced by the Authors in the field of tramway and metro electrical systems, where innovative criteria have been introduced in all aspects: general structure of the system – control philosophies – component design. The problem is faced here in the optics of reliability: besides reliability improvement intrinsically due to motorwheel conception (tractive effort being shared into several axes, so that the consequences of a failure have a smaller importance than in conventional solutions on the whole system), attention is focused on:
– means allowing a failure to be confined to the section where it occurs initially, with no influence on the others;
– capability of the central control unit (the micro actuating drive strategies on the knowledge of operative conditions on all single axes) to operate as an on-board diagnostic center;
– means allowing for quick replacement of damaged parts in the repair station.
An evaluation of reliability characteristics follows, related to some parameters that theoretical advancements in this area have shown as specially significant.
