Condition monitoring and diagnostics of machines — Vibration condition monitoring — Part 9: Diagnostic techniques for electric motors

This document specifies the procedures to be considered when carrying out vibration diagnostics of various types of electric motors. The four motor types covered by this document are

1. squirrel-cage induction,
2. wound-rotor induction,
3. salient-pole, and
4. DC.

NOTE            Motor types a) and b) are defined in ISO 20958.

This document is mostly applicable to motors with power above 15 kW.

This document is intended to be used by condition monitoring practitioners, engineers and technicians and provides a practical step-by-step vibration-based approach to fault diagnosis. In addition, it gives several examples for a range of machine and component types and their associated fault symptoms.

The procedures presented in this document can, in some cases, be applied to other types of electrical machines, such as generators, but there can be other specific techniques associated with such machines that are not included in this document.

The use of non-vibration quantities, such as voltage and current, to identify and analyse vibration-related faults in electric motors is outside the scope of this document.