Ricerc@Sapienza

Nowadays there are 3 % of missed start-ups of emergency gensets in Italian hospitals every year. The subject of this work is the analysis of the failure to start an emergency genset due to the failure of the batteries. The work is based on ten years statistics of maintenance on hospital facilities. A real case study is here described; measurements were made on a 1000 kVA genset of a hospital to study the real operating conditions of the system. The whole electrical, mechanical and dynamic model of the starter system of a genset is studied.

In many applications, like hospitals, the reliability of the emergency electrical supply is a critical issue, since the continuity has to be guaranteed at any time. The backup system usually consists of gensets and electrical starters (DC motors), supplied by lead-acid batteries. It is a fact that the latter are responsible for most genset cranking failures occurring in hospitals. Therefore, the reliability of the storage system should be improved to increase the Overall Mean Time Between Failures (MTBF) of the whole backup system.