© TPI Europe 2021
7 TPI 9085 User Guide V1.0
Bearing Noise
(
BDU)
Below the displayed ISO value and to the left is the value of bearing noise (high frequency
vibration) in
Bearing Damage Units
(BDU), where 100 BDU corresponds to 1g RMS
(average) vibration measured above 1kHz. This is a measure of the wear state of the
bearings in the equipment being monitored. The higher the number, the more worn the
bearing.
It is commonly held that 1g of high frequency vibration (100 BDU) corresponds to a
relatively high level of bearing noise and so can be considered indicative of a damaged
bearing. In other words, it may be helpful to think of the Bearing Noise figure as being
very roughly equivalent to
“percentage”
of bearing wear. By default, the bearing noise
is displayed on a
Red
background if it is above 100 BDU, an
Amber
background between
50 and 100 BDU and a
Green
background below 50 BDU. However, the BDU alarm levels
can be changed using the
Manual Setup
menu (see section 2.3.2.1).
Total acceleration (g)
This is the RMS (average) value of the total vibration acceleration measured by the meter
over its entire frequency range (2Hz to 10kHz). This reading is shown in units of
g
(
Earth’s
gravitational constant, where 1g = 9.81 m/s
2
).
Displacement
Pressing either the left (<) or right (>) arrow button when the reading screen is displayed
will cause the meter to display RMS
displacement (in mm or thou) on a blue background.
Pressing either left or right arrow button again will revert to display of the ISO value (mm/s
or inch/s).
Temperature
The
measured temperature will be displayed at the bottom of the LCD. Once the “Take
Measurement” key is pressed the 9085 will take a vibration measurement and then begin
a 10 second countdown which allows the temperature sensor to stabilize. After the
countdown the temperature will be displayed. Various settings can be adjusted for the
temperature range like save mode, minimum save time, auto save time, and whether the
temperature readings are saved with the vibration readings. These are explained later in
the manual.
2.2.2 Vibration Analysis
Pressing the down arrow button brings up a display similar to that shown below, which
shows the readings of vibration velocity (mm/s or inch/s), or displacement (mm or thou) if
selected, broken down into each of 3 bands.
The display shows the vibration level in frequency ranges that are all based on multiples
(1X, 2X and 3X) of the specified
Run Speed
of the machine as displayed beneath the 3
bar graphs.
