FAILURE ANALYSES AND ACCELERATED DEGRADATION TEST FOR AC FAN MOTOR

摘要

This paper presents failure analyses and an accelerated degradation test of AC fan motorsfor refrigerators. Several analyses such as destructive physical analysis, blade fracture analysis, FEM, and fan oscillation are made to identify root causes of failures for the field samples. Next, an accelerated degradation test is planned to determine the significant factors and to predict the lifetime for the predominant failure mode, locked-rotor by clinger between shaft and bearing. The amount of oil, temperature, voltage, length of shaft, and unbalance are considered as accelerating factors, and 16 test conditions are selected by design of experiment using orthogonal array. Data analysis shows that RPM is affected by voltage only, but is not degraded significantly in time. It is also shown that voltage and the amount of oil affects the change of oil amount, which decreases in time. The degradation characteristic of AC fan motor will be characterized and its accelerated degradation model will be made after more testing.