Monitored Quantities; Vibration - WEG Motor Scan Manual General De Instalación Y Operación

5.2. MONITORED QUANTITIES

5.2.1 Vibration

The WEG Motor Scan measures the effective or RMS vibration (mm/s) in three axes (A Axial, Rx Radial X, and
Ry Radial Y) as shown in Figure 5.4 below
The monitoring of RMS vibration levels and the evaluation of operating trends and patterns are used to indicate
circumstantial or permanent changes in the application. As a result, a more accurate assessment can be made
to determine the cause of the change and whether it is a machine failure.
Item 7 of this manual contains the guidelines for installing the WEG Motor Scan on the motor surface where the
stator is located. This position was carefully analyzed and chosen so as to enable the collection of information
on temperature close to the stator area, motor vibration and other information for future features. Although it is
not a vibration measuring position recommended by ISO standard 10816-3 (*), commonly used in industrial
predictive maintenance programs, ISO standard 13373-1 (**), also used in predictive maintenance programs,
allows vibration sensors to be installed in other positions that produce proper vibration information. The studies
carried out at WEG proved the suitability of the measuring point with the same indication of trends obtained in
the measurements in the bearings.
Figure 5.5 shows the ratio, in dB, between the simultaneous vibration measurements of the WEG Motor Scan
and a standard calibration accelerometer in the same point on an electrodynamic exciter capable of producing
vibrations over a wide frequency range. The WEG Motor Scan has an excellent response in comparison to the
standard accelerometer within the operating frequency range of up to 820 Hz for evaluating the overall RMS
vibration value.
Figure 5.5 – Ratio between the WEG Motor Scan responses and a standard calibration accelerometer simultaneously subjected to the
Vibration measurements performed by the WEG Motor Scan can be compared to conventional vibration
equipment, but the measurement location used as a reference for this comparison should be as close as
possible to the standard mounting location on the Motor (see Figures 7.2 and 7.3). In this condition, no or little
variation between measurements is expected. Figure 5.6 illustrates such condition.
Figure 5.4 - Definition of the coordinate axes on the WEG Motor Scan
Resposta em Frequência WEG Motor Scan
WEG Motor Scan Frequency Responses
5
0
-5
-10
-15
-20
1 10
Frequency (Hz)
same vibration levels within a wide frequency range.
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