WEG Motor Scan Manual General De Instalación Y Operación página 41

base level in the application and/or experience of the user. The levels defined in the standard are for points on
the bearings of the motor or coupled machine. The redefinition should take into account the motor mounting
base type and the position of the sensor away from the bearings. Table 5.1 is a reference in case there are no
historical values for the application and measurement point.
RMS Vibration Speed
[mm/s]
V ≤ 2.8
2.8 < V ≤ 5.6
5.6 < V ≤ 8.9
8.9 < V ≤ 13.8
V > 13.8
Lettering:
NORMAL
ALERT
CRITICAL
Below are some examples that may help interpret the vibration levels monitored by the WEG Motor Scan:
Example 1 – The chart of Figure 5.8 shows that the RMS value in one of the directions exceeded the alarm
level and the critical level at a given point in time, but it returned to the operation standard value in the following
measurements. The event may have been caused by some kind of overload or some kind of shock at the
moment of the measurement.
Example 2 – The chart in Figure 5.9 shows that an event occurred between the end of May and the beginning
of June. The vibration pattern, which was 4 mm/s before this period, dropped down to 2 mm/s. The technician
considered the admitted values were high and performed a maintenance job. After the maintenance, the RMS
values lowered by half.
Table 5.1 – Vibration alert and critical level limits - ISO 10816-3
Power ≤ 300kW
Group 2 of ISO 10816-3
Rigid Base
Figure 5.8 – Chart of the RMS values on the Y axis over time
Figure 5.9 – Chart of the RMS values on the X axis over time
Group 1 of ISO 10816-3
Flexible Base Rigid Base
Manual of Electric Motors
www.weg.net
Power > 300 kW
Flexible Base
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