ISO 10816-5:2000 pdf download

ISO 10816-5:2000 pdf download.Mechanical vibration— Evaluationof machine vibration by measurementson non-rotating parts – Part 5: Machine sets in hydraulic power generatingand pumping plants.
4.2 Measurement type
Absolute bearing housing vibration measurements are commonly made on hydraulic machine sets using seismic transducers measuring the vibration velocity 1’rms in millimetres per second or, after electronic integration, the vibration displacement .s in micrometres. The vibration displacement .s can also be measured directly as a relative quantity using displacement transducers in the case where a rigid non-vibrating support can be found.
Because of the special nature of the vibratory behaviour of hydraulic machines and their different speed ranges, these quantities have favoured ranges of application as follows:
a) For low-speed machines (below 300 r/min), the preferred measurement quantity is the vibration displacement s. If the spectrum is expected to contain high-frequency components, the evaluation should normally be based on broad-band measurements of both displacement and velocity.
b) For medium- and high-speed machines (300 r/min to 1 800 r/min), the preferred measurement quantity is the vibration velocity 1’rms If the spectrum is expected to contain low-frequency components, the evaluation should normally be based on broad-band measurements of both velocity and displacement.
4.3 Measurement locations and directions
Measurement tasks A and B (see clause 1) require measurements to be taken on exposed parts of the machine that are normally accessible and are representative locations for the so-called force flow in the supporting structure, for example on all main bearings of the machine set. Typical examples of measurement locations for hydraulic machines are shown in Figures 1 to 5.
Care shall be taken in this context to ensure that measurements reasonably represent the vibration of the bearing housings and do not include any local resonance or amplification. The locations and directions for vibration measurements shall be such that they provide adequate sensitivity to the dynamic forces of the machine under various operating conditions. Typically, this will often require two orthogonal radial measurement directions on each bearing cap, pedestal or housing. For low-speed machines with a horizontal shaft axis, such as bulb-turbines as shown in Figure 2, the measurement locations and directions shall be determined with great care.
CAUTION: The vibration measured at the lower guide bearings of vertical machines may sometimes be misinterpreted; the vibration level measured at such bearings and their surrounding supports which are rigidly embedded in the buildings is sometimes produced by hydraulic forces, directly transmitted from the hydraulic machine via the foundation. Such vibrations do not necessarily give a correct image of the vibration of the rotating shaft system.
For horizontal machines when using portable measuring instrumentation, take measurements in the vertical and horizontal directions 90° apart (perpendicular to the shaft axis) and, if possible, in the axial direction (parallel to the shaft axis) as shown in Figure 5.
A single transducer may be used on a bearing cap or pedestal in place of the more typical pair of orthogonal transducers if it is known to provide adequate information about the magnitude of the machine vibration. However, caution should be observed in evaluating vibration from a single transducer at a measurement location, because it may not be oriented to provide a reasonable approximation to the maximum value at that location.
In the case of vertical or inclined machine sets, the locations and directions that give maximum vibration readings shall be used, for example the stiff and the elastic axis (this is important for cases with spider arm support constructions), and the specific location and direction shall be recorded with the measurement. If possible, the setting of the transducers at different bearings should be in line. For vertical machines, the preferred measurement directions are upstream and 900 to that.
For monitoring purposes (task A) only, in some cases measurement locations may be reduced to the most important ones, mainly at machine sets with four or more bearings. The selection should be based on vibration performance analyses, simulating all types of faults or disturbing effects. Preferred measuring locations should be those where possible disturbing events produce significant bearing housing amplitudes (velocity or displacement).