Proposal for Acceleration Levels for Antifriction Bearings

Displacement and velocity vibration acceptance levels are defined by electrical machine manufacturing standards such as IEC and NEMA, which are used to determine whether a machine meets approval criteria. The ISO 20816 standards family provides guidelines for monitoring displacement and velocity vibration levels in machines. Additionally, IEC 13373-3 offers diagnostic guidance through vibration analysis. While it does not define specific vibration criteria for assessing machine condition, it offers a valuable method for evaluating bearing health by analyzing the peak and RMS values of vibration acceleration. Earlier versions of IEC and NEMA standards included criteria for vibration acceleration in machine approval processes. However, the commonly used measurement range of 10–1,000 Hz is inadequate for effective bearing vibration monitoring. Currently, aside from the guidance in ISO 13373-3, there is no established normative criterion for approving rotating electrical machines based on acceleration measurements above 1,000 Hz. This study aims to monitor 100 new electric machines during factory testing to establish appropriate amplitude limits for vibration acceleration. Measurements will be conducted using the WEGscan 100 instrument under various operational conditions, including cold and hot states, uncoupled operation, dualfrequency method, and coupling to a dynamometer.