SPM A2010 - Verify the Reading and Locate the Source

47
Technical data are subject to change without notice.
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Verify the Reading and Locate the Source
Before taking the first reading, you have to check the
measuring point and the installation of the adapter or
transducer, if any. Make sure that the seat surface of
the installed adapter or transducer has firm contact
with the material of the bearing housing.
The contact surface of adapters must be clean and
smooth. The transducer with quick connector must be
firmly attached to the adapter. If the probe is used, it
must be pointed straight at the bearing and held
steady during measurement.
Verifying the Reading
Do not rely on initial or abnormal readings without
making sure that they are correct:
• Check bearing data, NORM and TYPE setting.
• Measure with an accmulation of at least 3, to
make sure to get reliable reading.
Identify the Shock Pulse Source
Shock pulses are strongest close to the source. They
spread through the material of all machine parts, but
are damped (loss of signal) with distance and when
passing through interfaces in the material.
• Measure with the probe transducer on and near
the bearing housing to find the strongest shock
pulse source.
• Listen for unusual noises.
Sources of Interference
Any kind of metallic clatter, scraping or hard impacts
produces shock pulses which may interfere with the
measurement on the bearings. Some of the more
common sources of interference are:
• Shocks between poorly fastened machine feet
and foundation.
• Rubbing between shafts and other machine parts.
• Loose parts striking the machine frame or the
bearing housing.
• Excessive play and misalignment of couplings.
• Vibration in connection with loose parts and
excessive bearing play (vibration alone does not
affect the reading).
• Cavitation in pumps.
• Gear tooth damage.
• Load and pressure shocks arising during the
normal operation of certain machines.
Fig. 24
Fig.26
Check:
- Basic bearing data, NORM and TYPE setting
- Measuring point in the load zone
- Probe pointed straight at the bearing
- Adapter (transducer) properly mounted
- Adapter surface clean, undamaged
- Quick connect transducer firmly attached
Excessive
play
Gear tooth
damage
Cavitation
Play,
scraping
Fig 25