Microlog
®
MX series FFT analyser analys er and bump test module
The FFT analysis and bump test module is designed for use with the MX series of products within the Microlog Mi crolog family. The analyser transforms the MX into a powerful, yet easy to use tool for measuring noise or vibration signals, and breaking them down into their component frequencies. The user friendly interface displays spectrum and phase information in a simple, easy to understand format. Enabling you to quickly characterise your machinery and make a first pass diagnosis or identify areas for further diagnosis. The module also makes make s it quick and easy for an operator to assess the motion between two points. By providing a ‘phase vector’ reading (needed for diagnosis of some machine faults) an operator can build a picture of the relative motion of individual parts of the machine. Placing sensors, setting up and taking measurements measurements can all be done without the need to stop the machine running. No
tachometer reference is required as the phase measurement is taken by cross-referencing channels one and two. This allows for analysis of machinery with burried or covered shafts such as gear boxes and pumps. A key benefit of this module is that it enables non-experts to carry out simplified checks for common machine faults, including: • Unbalance – Identify unbalance unbalance helping to increase machinery and bearing life and improve productivity. productivi ty. Common types of unbalance that can be identified are: – Force unbalance – in-phase and steady. steady. – Couple unbalance – 180° out of phase on same shaft. – Overhung rotor unbalance – Often both force and couple unbalance are present. • Eccentric rotor – Highlight offset rotation in gears, bearings or motor armatures. • Bent shaft – Identify problems causing high axial vibration reducing machinery efficiency.
• Misalignment – Identify I dentify potential axial vibration and associated coupling problems.
Key features • Single FFT spectrum spectrum display plus plus phase vector – provides a simplified interpretation of vibration data. • 2 Hz to 40 kHz, 100–12 800 800 lines of resolution. • Phase reading shown as a simple vector diagram – no need to stop a running machine saving time and increasing oper-
ation efficiency. • Overall vibration severity reading. • True peak and true peak-peak detection. • Live display of signal spectrum. spectrum.
Analyser & bump test details Input signal types:
Accelerometers, velocity transducers, displacement probes
Y axis scaling units:
Acceleration (g, m/s2), A–V (single integration), A–D (double integration) Velocity (IPS, mm/s), V–D (single integration) Displacement (µm, mil, thou) gE, time
Measurement types:
Overall, spectrum, time wave form, phase
Display:
x axis – Hz, CPM y axis – linear, log
Input signal range:
±40 V max
ESPTM filters:
0,6–1,25/1,25–2,5/2,5–5/5–10/10–20 kHz
Signal scaling:
RMS, peak, peak to peak, true peak, true peak to peak
Bearing condition:
gE
Averaging:
Exponential – 5 averages Overlap – 50 % Bump test – Peak hold or exponential
High pass filters:
Off/2/10/70 Hz
• Bump (rap) test – identify resonant frequencies that can cause excessive noise or vibration. • Transfer data spreadsheet packages such as Excel® or into the analysis and reporting module (CMSW-ANR-EN).
Bump test The bump (rap) test functionality is also included with this module. It enables you to carry out tests for the identification of the natural resonant frequencies of a mechanical structure. In some cases the presence of a resonance can cause excessive levels of vibration and/or noise. This test helps you to identify the source of spectral components using data gathered from an accelerometer or other sensors.
Build quality and some mechanical faults such as cracking can sometimes be identified by a shift in the natural frequency. As such this module can also be applied to applications like:
Ordering information • CMXA-AAB-EN – FFT analyser and bump test module
• Turbine blade testing – ensuring turbine blades do not have any major natural frequencies that coincide with the operating speeds of the turbine or its integer multiples. • Structural mechanical integrity – identifying weak or unstable structures prior to failure. • Crack detection in metallic components – cracked or poorly bonded products will have less stiffness resulting in a change in natural frequency. SKF and Microlog are registered trademarks of the SKF Group. All other trademarks are the property of their respective owners. © SKF 2005 The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless permission is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein. Publication 5598 EN
SKF Condition Monitoring Centre (Livingston) Ltd 2 Michaelson Square, Livingston Scotland, EH54 7DP Tel: +44 (0) 1506 47 00 11 Fax: +44 (0) 1506 47 00 12
www.skf.com/reliability
