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Gearboxes are often a high maintenance source due to loading from the
machine being driven, excessive loading on the gear teeth, and
improper alignment of the gearbox to the motor. When vibration monitoring is
applied to the situation, unplanned shut-downs and costly repairs can be
minimized.
Monitoring a gearbox is
accomplished by installing an
accelerometer on each of the bearing housings for each shaft (4 bearings
for a two gear system, 6 for a three gear system etc...). An additional
accelerometer is mounted on the case to measure high frequency conditions
such as gear mesh. For bearing fault detection you will want to use a
vibration velocity monitor. For the
single accelerometer on the case, a
vibration acceleration monitor is recommended.
Larger gear boxes use journal bearings in
place of the standard rolling element bearings. This application requires
the use of proximity probes because
vibration is poorly transmitted to the bearing caps of journal bearings.
When proximity probes are used, CMCP540A
vibration monitors are specified.
A complete vibration monitoring system
includes:
-
One accelerometer mounted to each
bearing housing in the
gearbox -
CMCP1100
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One accelerometer mounted to the gearbox
case -
CMCP1100
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A Vibration Velocity Monitor for each
bearing -
CMCP530A
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One Vibration Acceleration Monitor for
gear mesh monitoring - CMCP525A
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Options include:
For additional reading STI offers several
application notes with a more in depth discussion at
STI Application Notes |
