IMV CardVibro Air2, User Manual

Page: 42 / 52

WiFi Portable Vibrometer
VM-2012 Air2
42/52
9-2. Bearing Evaluation
In order to evaluate bearing, we have established the guideline using the value of the E3 envelope
acceleration.
The values in the chart below shall be applied only to the general guidelines. The best way to
make a judgment on the severity is to take the trend of measurement results into consideration.
Classes:
(a) Class 1
Inner Diameter of the Bearing: From 200 to 500 mm
Number of Rotations: Less than 500RPM
(b) Class 2
Inner Diameter of the Bearing: From 50 to 300 mm
Number of Rotations: From 500 to 1800 RPM
(c) Class 3
Inner Diameter of the Bearing: 20 to 150 mm
Number of Rotations: 1800 or 3600RPM
Judgment will be made based on the peak of the E3.
As shown in the diagram in the following page, the program will select the applicable criteria
based on the inner diameter of the bearing and the number of rotations of the concerned
machinery.
The Enveloped Acceleration Classification ( CL1, CL2 or CL3 ) that best describes the general size
and speed of the bearings being measured should be selected.
Options are:
CL1: Bearings with a bearing bore diameter be-tween 200 and 500 mm (7.9 and 19.7
in.) and a shaft speed below 500 r/min.
Alert: 1 gE
Danger: 2 gE
CL2 (default): Bearings with a bearing bore diameter between 50 and 300 mm (2.0 and 11.8 in.)
and a shaft speed between 500 and 1 800 r/min.
Alert: 2 gE
Danger: 4 gE
CL3: Bearings with a bearing bore diameter be-tween 20 and 150 mm (0.8 and 5.9 in.)
and a shaft speed from 1 800 to 3 600 r/min.
Alert: 4 gE
Danger: 10 gE
1G=9.806m/s^2