Rotating Machinery Testing
Rotating machinery tends to spend long periods of time in steady-state operation. The vibration signatures recorded by a continuous monitoring system can capture problems such as imbalance due to blade erosion or loading and misalignment due to thermal cycling.
But such measurements may not reflect some of the more subtle degradation a machine may experience with age and wear. However, every time we stop or start a processing train we have an opportunity to learn a lot more about its mechanical health. Measuring 3D vibration Waterfalls (amplitude versus frequency versus time or RPM) during a shutdown or run-up provide a wealth of information. Using a tachometer signal to Order-Normalize such measurements simplifies understanding the relationship of fixed-frequency resonances and rotation-related forcing functions.
Brief instabilities such as shaft whirl and whip encountered during transient operation indicate the need to inspect bearings and adjust lubricant pressures. Other Spider and CoCo diagnostic displays such as orbit diagrams give a clear picture of shaft and bearing problems including dry rub, oil whirl and various misalignments.
Rotating Machinery Testing Applications
Rotating Machinery Capabilities
Commissioning and Shutdown Waterfalls
Order Tracks (Amplitude of an Order versus RPM)
Order-Normalized Spectra
Orbit Diagrams
Reanalysis of Recorded Data
One & Two-Plane Balancing
We recently republished a classic white paper about dynamic signal analysis.
Our team is thrilled to announce the 11.1 version of Engineering Data Management (EDM) software. Packed with a range of new features and improvements, this update is designed to elevate the user experience.
DSA is often referred to Dynamic Signal Analysis or Dynamic Signal Analyzer depending on the context. DSA uses various technologies for digital signal processing. Among them, the most fundamental and popular technology is based on the so-called Fast Fourier Transform (FFT). The FFT transforms the time domain signals into the frequency domain. To perform FFT-based measurements, it is important to understand the fundamental issues and computations involved.
The latest release of version 2.2 CoCo Software includes notable updates such as support for 1 hz resolution, an IEPE powered tachometer, Waterfall & Colormap signal reviews, and the ability to sync VDS user profiles on a CoCo device.
The auto-wake feature is a new and powerful function provided in EDM 10.0 software. This feature allows users to set up a wake-up alarm for Spiders to power on, perform a test, and power off. Users can upload up to 8 predefined tests and run these in Black Box mode (without a connection to a computer or network to run). This convenient mode allows users to acquire data autonomously or with little user intervention.
Some data acquisition applications will inevitability run into one of the most common problems of the information age: information overload. Today, modern DAQ systems, such as the highly versatile Crystal Instruments Spider product line, can store significant amounts of vibration data. Now, memory limitations are significant. However, sifting through large amounts of data in order to capture a small transient event is undesirable.
Crystal Instruments is excited to announce the release of EDM 10.0, the latest software version for all Spider and CoCo products serving advanced and fundamental industries in addition to furthering academic advancements.
Founded in 1996, Crystal Instruments designs and manufactures instrumentation products for machine vibration monitoring, dynamic measurement, and environmental testing. The products are developed in Silicon Valley and our modern lab in North Carolina. Crystal Instruments products are thoroughly tested on a variety of vibration shakers and environmental chambers in our lab during the design phase to meet the extreme requirements of military and aerospace applications.
Crystal Instruments is pleased to announce the release of EDM 9.1, the most reliable and powerful version available from Crystal Instruments.
The CoCo’s Save and Record functions are generally only discussed in the context of separate measurements. Although the Save and Record functions cannot be executed simultaneously, the CoCo is still able to store both the time waveform and FFT from the same set of original data. By exploiting the fact that FFT/block signals are always being buffered in the CoCo’s RAM, we can acquire the FFT signals while simultaneously recording the time waveforms to the SD card.
Featuring the highest sampling rate provided in the industry at 256 kHz. Handheld battery powered system with wired & wireless network options and 20V input range. Sync between multiple devices. Choose the convenient portable model or industrial model for permanent mounting.
The Spider-20H, Spider-20HE, and Spider-20i received a hardware upgrade to support an impressive 256 kHz samping rate on all 4 input channels. It is the highest sampling rate offered in the market of compact analyzers. The high sampling rate is especially beneficial for measuring high orders and transient capture in blast tests, pyroshock events, drop shock tests, crash tests, etc.
In addition to the high samping rate, the input range is expanded to 20V to capture larger signals.
Crystal Instruments EDM 9.0 release introduces new additions to the Spider product line featuring support for sampling rates up to 256 kHz.
The new Spider-80Hi and Spider-80Ci are scalable versions of the Spider system featuring the impressive new 256 kHz sampling rate. Recording can also be performed at sampling rates up to 256 kHz for all input channels, up to 512 channels per Spider system.
The compact, ultra-portable four channel version of the Spider has also been developed to support a 256 kHz sampling rate. Currently, three variations of the compact Spiders supporting the 256 kHz sampling rate are available: Spider-20H, Spider-20HE, Spider-20i.
Today’s engineering tools are the result of constant software development, but these developments aren’t always best for the end-user. Engineers who are heavily invested in their tools will be reluctant to switch to a new device. In a time where software is constantly changing, people don’t have the time to struggle with new software interfaces. Especially field technicians, whose job is to collect and analyze data, don’t like wasting time getting used to a new software interface. Their job is already complicated, and is only made worse with a complicated measurement device. If their tools are too complicated to use, engineers will look for a simpler solution.
There are often instances where it may be beneficial to add location information to your acquired data. With the CoCo-80X, these GPS signals can be acquired simultaneously with other measurements -- there is no need to carry a separate GPS device. The CoCo-80X’s large LCD and touch-screen interface makes it easy to use the analyzer and acquire data. All measurements are combined into a single test file, so there’s no need to manage files.
I’ve always wondered why some instruments in the market set their hardware input range to 10 V. Perhaps the hardware designer for these instruments possessed ten fingers and chose 10 V out of convenience. I can imagine their bosses eagerly approving the use of 10 V as well, because they too have ten fingers!
In response to industry demands for reliable vibration data collection and dynamic signal analysis with complex real-time processing, Crystal Instruments has developed the CoCo-80X. The instrument is equipped with a 7-inch LCD touchscreen, a dual-core DaVinci series 1GHz processor, and a wide-range of connection options including CAN Bus, USB 2.0, HDMI, Ethernet, and SD card. CoCo-80X is also Wi-Fi and GPS enabled.
The short answer is, “a lot!” DSA (dynamic signal analyzer) users will immediately be able to do more of what they already do, faster and easier. VCS (vibration control system) users will discover new and safer ways of testing products to requirement specifications.
One of the breakthrough features of the CoCo-80, Spider-80X, and Spider-81 is their outstanding dynamic range performance of 160 dBFS. This kind of performance has never before been achieved with such small, portable, and low cost devices. The main advantage of this high dynamic range is that it eliminates the need to adjust the input gain/range settings on the front end, thus simplifying the setup and measurement process. Both full scale 10 volt signals and very small microvolt signals are measured at the same time with no adjustments. This capability makes setup and testing more simplified in comparison with an instrument capable of only a lower dynamic range.
There are two steps for converting an analog signal into a digital signal – quantization in time (sampling) and quantization of amplitude. Any signal that goes through the sampling process is subject to the effect of aliasing. The common use of the word ‘alias’ is used to describe a false name or identity, which is similar to how the term is used in signal processing.