Importance

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Abstract

The present disclosure provides a formulated conductive grease for an associated bearing that can be used in a drive system, such as a variable frequency drive system for motors having a formulation sufficient to reduce the voltage build up that causes damaging electric discharge machining (“EDM”) on rotational bearing supported surfaces, such as inner and outer races, while still maintaining a grease composition suitable for bearing long life at operational temperatures. The higher conductivity of the inventive grease results in lowering of the threshold voltage of pulse discharges, which consequently decreases the energy release in each pulse and the resulting bearing temperatures, avoiding bearing damage. The disclosure further provides a bearing lifetime prediction model given typical discharge conditions from both Si and SiC inverters using a bearing state of health (SOH) metric.

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First Claim