LMS offers a complete solution for accurate measurements of the torsional variations of one or multiple shafts.
The LMS SCADAS Mobile torsional vibration module (SCM-RV4) acquires, offline or in real-time, up to 4 tacho pulse streams at a high pulse rate. These pulses are translated into accurate angular velocity and displacement time histories at high aliasing-free bandwidth. Both TTL as well as analogue, unconditioned pulse streams are supported. Alternatively, the RV4 module is able to capture up to two incremental encoder signals.
The LMS Test.Lab Torsional Vibration Analysis software lets engineers analyze the torsional vibrations of rotating machinery with single or multiple shafts. RPM order sections can be extracted from fixed sampled frequency spectra as well as from data sampled synchronously with RPM, giving leakage-free, razor-sharp order cuts. The software is able to perform and process real-time observations of shaft angular displacements, speed or acceleration, torsion over shafts, belt transmission errors or other specific metrics.
Acquired tacho-data can be corrected for missing or double pulses, or for unevenly spread pulses (pitch correction). Results can be viewed alternatively in RMS or peak format in order to match the legacy data. To correlate torsional vibration phenomena with other NVH-related problems, the LMS solution simultaneously records tacho channels signals with other quantities such as acceleration, pressure or strain.
A correct test set-up is crucial to accurately measure torsional vibrations. Faster and simpler set-ups are made possible with the LMS Test.Lab zebra-tape correction algorithm. Using tacho-pulse streams from a zebra-tape wrapped around the rotating shaft, the LMS Test.Lab algorithm is able to correct the error generated by the butt-joint (the point where the two sides of the zebra-tape come together
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Reinforcing its commitment to make quality, fuel-efficient, safe and technologically advanced vehicles, the Ford Motor Company has radically improved vehicle quality and is working hard to rank number one in quality performance. This turnaround strategy hinges on focused efforts throughout the Ford organization, including the FEAD group where LMS Test.Lab helps double the number of torsional and other vibroacoustic tests to ensure high quality standards on all the automaker’s US front-end accessory drive designs.
Business is booming at Moventas, a leading tier-one supplier of gearboxes for wind turbines. Company sales increased 40% last year, reflecting tremendous growth of this alternative resource in the face of sky-high energy prices. According to the World Wind Energy Association, global installed wind turbine capacity has grown ten-fold in the last ten years and has increased 25% just in the past year. Predictions from the association indicate that the 74 gigawatts of current worldwide wind-powered electrical generation will more than double by 2010, when levels are expected to reach 160 gigawatts.
Noise and vibration performance plays an important role in the development of rotating components, such as engines, drivelines, transmission systems, compressors and pumps. The presence of torsional vibrations and other specific phenomena require the dynamic behavior of systems and components to be assessed accurately in order to avoid comfort and durability related problems. The innovative LMS QTV (Quad Torsional Vibration) modules allow engineers to analyze the torsional vibrations of transmission-related systems and components in context of other synchronously processed noise and vibration performance characteristics. 
