ABMA 15242-1:2016 pdf download

ABMA 15242-1:2016 pdf download.Rolling bearings — Measuring methods for vibration
1 Scope
This part of ISO 15242 specifies measuring methods for vibration of rotating rolling bearings under established measuring conditions, together with calibration of the related measuring systems.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 286-2, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes — Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts ISO 2041:2009, Mechanical vibration, shock and condition monitoring — Vocabulary ISO 5593, Rolling bearings — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041, ISO 5593 and the following apply. 3.1 error motion undesired radial or axial (translational) motion or tilt (angular) motion of an axis of rotation, excluding motions due to changes of temperature or externally applied load 3.2 vibration mechanical oscillations about an equilibrium point Note 1 to entry: The oscillations may be periodic or random. [SOURCE: ISO 2041:2009, 2.1, modified] 3.3 transducer device designed to convert energy from one form to another in such a manner that the desired characteristics of the input energy appear at the output Note 1 to entry: The output is usually electrical. Note 2 to entry: The use of the term “pick-up” is deprecated. Note 3 to entry: Examples of types of transducers used in vibration measurement are the following: a) piezoelectric accelerometer; b) piezoresistive accelerometer;c) strain-gauge type accelerometer; d) variable-resistance transducer; e) electrostatic (capacitor/condenser) transducer; f) bonded-wire (foil) strain-gauge; g) variable-reluctance transducer; h) magnetostriction transducer; i) moving-conductor transducer; j) moving-coil transducer; k) induction transducer; l) laser vibrometer. Note 4 to entry: Other types of transducers such as dynamic force transducers may be used, provided their signal can be converted to displacement, velocity or acceleration. [SOURCE: ISO 2041:2009, 4.1, modified — Note 3 to entry and Note 4 to entry have been added.] 3.4 filter wave? filter analogue or digital device for separating oscillations on the basis of their frequency, introducing relatively small attenuation to wave oscillations in one or more frequency bands and relatively large attenuation to oscillations of other frequencies 3.5 band-pass? filter filter (3.4) which has a single transmission band extending from a lower cut-off frequency greater than zero to a finite upper cut-off frequency 3.6 nominal upper and lower cut-off frequencies cut-off frequency f upp and f low nominal frequencies that define the band-pass filter (3.5) 3.7 root mean square velocity rms velocity v rms (t) square root of the average of squared values of the vibration velocity within a time interval, T Note 1 to entry: Root mean square value can also be used for displacement and acceleration. Note 2 to entry: In the first edition of this part of ISO 15242, root mean square was abbreviated as r.m.s. 3.8 fundamental period period smallest increment of time for which a periodic function repeats itself Note 1 to entry: If no ambiguity is likely, the fundamental period is called the period. [SOURCE: ISO 2041:2009, 2.32]
4 Fundamental concepts
4.1 Bearing vibration measurement The diagram in Figure 3 shows the fundamental elements of bearing vibration measurement and the factors that influence the measurement. The numbers in Figure 3 correspond to subclauses of this part of ISO 15242.A rotating rolling bearing will, ideally, have no resistance to externally applied forces in the rotational direction, i.e. zero frictional torque. Depending on the type of external loading the bearing is designed to support, the bearing will exhibit stiffness in any or all of the five remaining degrees of freedom. For example, a bearing with self-aligning capabilities may support radial and axial loading, but will, ideally, exhibit no stiffness in the two tilt directions. Other bearings may be designed to allow free axial motion while exhibiting radial and tilt stiffness. 4.3 Bearing error motion Displacement of the axis of rotation of a rotating bearing in any of the five non-rotational degrees of freedom for which the bearing is designed to support load is known as bearing error motion. This includes any displacements associated with rotation of the bearing, but excludes displacements due to thermal drift or changes in externally applied load. Error motion is reported in terms of displacement and characterizes the deviation from perfection of an axis of rotation.