ISO/TC 108/SC 2/WG 10 - Basic techniques for vibration diagnostics

This document sets out the specific procedures to be considered when carrying out vibration diagnostics of various types of fans and blowers. 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 a number of examples for a range of machine and component types and their associated fault symptoms. The approach given in this document is based on established good practice, put together by experienced users, although it is acknowledged that other approaches can exist. Recommended actions for a particular diagnosis depend on individual circumstances, the degree of confidence in the fault diagnosis (e.g. has the same diagnosis been made correctly before for this machine), the experience of the practitioner, the fault type and severity as well as on safety and commercial considerations. It is neither possible nor the aim of this document to recommend actions for all circumstances.

ISO 13373-9 specifies procedures to be considered when carrying out vibration diagnostics of various types of electric motors. The four motor types covered by ISO 13373-9 are squirrel-cage induction, wound-rotor induction, salient-pole and DC motors. NOTE The first two types are defined in ISO 20958. ISO 13373-9 is mostly applicable to motors with power above 15 kW. ISO 13373-9 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 a number of examples for a range of machine and component types and their associated fault symptoms. The procedures presented in ISO 13373-9 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 ISO 13373-9. 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 ISO 13373-9.

ISO 13373-7:2017 gives guidelines for specific procedures to be considered when carrying out vibration diagnostics of various types of machine sets in hydraulic power generating and pump-storage plants (hydropower units). It 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 includes a number of examples for a range of machine and component types and their associated fault symptoms.

ISO 13373-2:2016 recommends procedures for processing and presenting vibration data and analyzing vibration signatures for the purpose of monitoring the vibration condition of rotating machinery, and performing diagnostics as appropriate. Different techniques are described for different applications. Signal enhancement techniques and analysis methods used for the investigation of particular machine dynamic phenomena are included. Many of these techniques can be applied to other machine types, including reciprocating machines. Example formats for the parameters that are commonly plotted for evaluation and diagnostic purposes are also given. ISO 13373-2:2016 is divided essentially into two basic approaches when analysing vibration signals: the time domain and the frequency domain. Some approaches to the refinement of diagnostic results, by changing the operational conditions, are also covered. ISO 13373-2:2016 includes only the most commonly used techniques for the vibration condition monitoring, analysis and diagnostics of machines. There are many other techniques used to determine the behaviour of machines that apply to more in‑depth vibration analysis and diagnostic investigations beyond the normal follow‑on to machinery condition monitoring. A detailed description of these techniques is beyond the scope of ISO 13373-2:2016, but some of these more advanced special purpose techniques are listed in Clause 5 for additional information. For specific machine types and sizes, the ISO 7919 and ISO 10816 series provide guidance for the application of broadband vibration magnitudes for condition monitoring, and other documents such as VDI 3839 provide additional information about machinery‑specific problems that can be detected when conducting vibration diagnostics.

ISO 13373-3:2015 sets out guidelines for the general procedures to be considered when carrying out vibration diagnostics of rotating machines. It is intended to be used by vibration practitioners, engineers and technicians and provides a practical structured approach to fault diagnosis. In addition it gives examples of faults common to a wide range of machines. NOTE Guidance for specific machines is provided in other parts of ISO 13373.