ISO 20816-5:2018 pdf free

ISO 20816-5:2018 pdf free.Mechanical vibration – Measurement and evaluation of machine vibration
For relative measurements, it is common to install the transducers on the bearing housings as close as possible to the guide bearings. They can then read directly on the bearing journals or, alternatively,on special shaft areas (i.e. machined tracks) that have been prepared to limit the total electrical and mechanical runout. In the case of segmental guide bearings, transducers can be mounted between the bearing pads using the guide bearing housing for support or directly on top of the pads but these latter methods are less frequently used.
Care should always be taken to ensure that the support for the shaft vibration transducers is very rigid.If this is not the case, the measured signal will not be representative of the relative movement between the shaft and bearing housing. This requirement can be assessed by static analysis of the structure or verification of the natural frequency of the supports of the vibration transducers by an impact test.The lowest natural radial frequency of the transducer mounting structure should be at least 10 times greater than the synchronous rotational frequency in order to eliminate any chance of resonance in the mounting support. If there is evidence of resonance in the supporting structure on which the shaft vibration transducer is mounted, this needs to be addressed before any signal measurement is taken.In addition, the structure or bearing housing on which the transducer is to be mounted should have a lowest natural radial frequency at least 10 times the synchronous rotational frequency.
Care should be exercised to comply with any specifications stated by the transducer manufacturer to maintain a free space around the transducer to avoid magnetic interference. Care should also be exercised in setting the gap between the transducer and the shaft to ensure that it is greater than twice the maximum radial bearing clearance in order to avoid damage to the transducer. If electrical cables are running inside the shaft and close to the surface, inductive sensors can be affected by stray magnetic fields.
It is important that the shaft surface where the vibration is being measured is free from blemishes,scratches, dents or any other surface defects. It is normal for the shaft track to be specially prepared for use with shaft displacement transducers so as to limit the combined electrical and mechanical runout to a very low value. ldeally the shaft track for vibration measurement should be prepared at the same time as the bearing journals.ISO 20816-5 pdf download.