"Life curve" of stator windings of asynchronous motors for elevators

Abstract

The relevance of the work is justified by the need to improve the operational reliability of stator windings of induction motors, installed in the main drive of elevators in residential buildings. Their failures are expensive to fix and entail long-term downtime. The main aim of the work is to estimate the reliability of stator windings of elevators induction motors and to construct the "life curve". The reliability is to be estimated using the failure information, obtained in the course of their operation. Research methods: The aim of the work had been achieved using probabilistic and statistical method with a help of the following software packages: MS Word, MS Excel, MathCAD. The utilized method is based on theorems of probability theory and mathematical statistics using collection and analysis of statistical data. Results: The authors have studied the failures of stator windings of elevators induction motors. The initial data set was constructed based on the research results. The data set consists of failures and censoring time of stator windings of elevators induction motors. The authors considered normal, exponential, log-normal and Weibull model as the operational reliability models. A MathCAD-based program was developed to evaluate operational reliability which allows building experimental distributions and further calculating parameters of theoretical distributions and reliability. The most appropriate reliability model was chosen based on the correlation between empirical and theoretical distributions. As a result the "life curve" of the stator windings of elevators was constructed; it can be further used to develop more effective system of maintenance and repair.

Keywords

• asynchronous motor
• passenger elevator
• hoist
• operating reliability
• failure
• censored samples