© Brüel & Kjær Vibro
● C106834.002 / V06 ●
Page 29 of 110
Technical alterations reserved!
Brüel & Kjær Vibro
│
Instruction VC-1800 Series
Installation and Operation of VIBROCONTROL
18xx
EN
UNRESTRICTED DOCUMENT
6.8
VIBROCONTROL 1850:
Setting of the First and Second Envelope Detector
Bearing damage is one of the most common faults in rotating machines and the envelope detector
is primarily used to detect and diagnose Rolling Element Bearing (REB) damage. When a fault
develops, the vibration becomes amplitude modulated due to periodic changes in the forces. The
low frequency vibrations are filtered away in order only to extract the modulated periodic
information from the more sensitive and pure envelope signal.
The envelope spectrum has shown several major advantages over other methods in very early
detection and fault symptom identification.
VIBROCONTROL 1850 has two integrated envelope detectors, which can be adjusted individually.
However, the envelope detectors are part of band 2 and as such are assigned to the bandwidth of
the band-pass filter selected in band 2. Please note that the choice of bandwidth in band 2 affects
the crest factor and kurtosis as well.
The envelope detector must be "enabled."
The envelope is measured in m/s² (g) RMS of the unit type selected in band 2. m/s2 (g) must
therefore be pre-defined in band 2 if envelope analysis will be used.