Rockwell Automation 1441-PEN25-Z Enpac 2500 Data Collector - Manual (Page 163)

Rockwell Automation Publication GMSI10-UM002D-EN-E - August 2012 163
Multi-channel Measurements Chapter 6
Figure 30 - Complex Orbit
As a rub becomes more severe or continuous, then the orbit becomes more
complex and possibly erratic, with bearing structural resonances being excited
and multiples of subsynchronous frequencies showing up.
Mechanical looseness caused by excessive wear tends to produce an orbit similar
to that of a rub. Subsynchronous effects show up as secondary loops. However, in
this case, shaft movement may be in a forward direction, rather than the reverse
direction that is typical of a rub.
Figure 31 - Typical Orbit Plot
See the Emonitor software online help for more information.
Set Up Orbit Measurements Definitions in the Emonitor Software
The Emonitor software and the Enpac 2500 support orbit measurement
definitions. This topic lists the unique characteristics of the data collector that
you may need to know when setting up and collecting orbit data:
• Set up a location in the Location pane for the two input channels.
The Location IDs must be different. Set the Lo. Channel for the first
location to 1. Set the Lo. Channel for the second location to 2.
• Set up a Collection Specification with Transducer set to Displacement.
• Set up a time measurement definition and a numeric measurement
definition for both locations.