Raw Data Time Streams
In many competitive tracking software products, the user can either conduct real-
time order tracking, or record the data with other tools and then post-process the
order tracks, but not both. The Spider, in conjunction with the Crystal
Instruments EDM software can perform real-time order analysis and tracking
and simultaneously record the time streams of all channels including the
dedicated tachometer channels. Crystal Instruments Order Tracking can record
up to 128 signal channels and two tachometer channels while performing real-
time order tracking and analysis.
Crystal Instruments Post Analyzer software can use the recorded signals to
perform off-line Order tracking and Analysis. Real time processing limitations, if
they exist, can be overcome using this feature.
Phase for Order Tracks
The Phase in Rotating Machine Analysis
Many mechanical faults are associated with certain orders, analyzing both order
magnitude and its phase can help you detect mechanical faults directly. For
example, a strong first order magnitude indicates imbalance in most cases.
Analyzing the first order magnitude can help you identify an imbalance problem.
Moreover, the magnitude and phase of the first order can help you correct the
problem by adding weights on the appropriate rotor positions. While it is possible
to balance a machine using magnitude-only measurements, employing measured
magnitude and phase reduces the number of machine stop/starts in the balancing
process by a factor of three or more.
As previously discussed, an order track is the measurement taken for an order,
i.e., normalized frequency, versus RPM. In most of the applications of engine
related test, the phase information of order tracks is not important. In rotating
machine analysis, the phase of the signal is vitally important.
Phase is a relative quantity and can only be measured between a pair of signals. It
indicates the time delay (at certain frequency) between the two signals. The phase
value can be translated into the difference in relative angle, relative position or
propagation time if additional information is known. (When we refer to the
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