Importance

Loading Importance Indicators...

Abstract

The mean number of elevator door reversals, .mu., in groups of related door reversals, and the standard deviation, .sigma., from the mean, are used to determine the likelihood that door reversals are caused by passenger interference; the likelihood is low if a recent number of reversals exceeds .mu.+3.sigma., , is medium if two out of three recent reversals exceed .mu.+2.sigma., and otherwise is high. The floors at which related notable elevator features occur are compared to determine a floor factor, F, depending on whether the notable feature occurs only at one floor or at more than one floor. Estimated probabilities, P'(S/C), that any component, C, will result in a symptom, S, (where S=first and second notable features in a related group and the accompanying floor factor, F) are provided by experts; the probability of P'(C) of any failure being of any given component is determined from failure history; and an estimated probability, P'(C/S), that symptom S is caused by component C is given by: ##EQU1##

Loading the Abstract Image...

First Claim