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StressWave Frequently Asked Questions


Is Stress Wave Energy analysis the same thing as vibration analysis?

No. Stress Wave Energy analysis is quite different than vibration analysis. The Stress Wave Energy analysis system was actually designed to overcome the problems that continue to plague vibration analysis effectiveness. The fundamental problem with vibration data is that traditional vibration accelerometers are unable to differentiate a subtle signal due to the early stages of damage from the normal signal that results from the healthy machine. Any machine has inherent vibration levels that are going to be stronger than those resulting from the early stages of damage. Stress Wave Energy analysis completely discounts the dynamic motion of the machinery and simply listens for shock and friction raising events. Once detected, the energy content of those shock and friction events are measured and trended for a predictive indication of how machinery condition is deteriorating over time. Also, vibration analysis becomes more inefficient at lower operating speeds as the energy released by a defect is not sufficient to excite the mass of the machine to shake.

Can SWAN technology identify which component is damaged?

Yes. A damaged component can be determined using two techniques. The first is quite simply proximity. If several sensors are in use, the sensor that has the biggest increase in Stress Wave Energy (SWE™) is closest to the damaged component. The second method of isolating the source of damage is evaluating the signal's spectral content (pulse amplitudes as a function of the fundamental and harmonic frequencies at which they occur). The filtered signal containing only friction and shock events is the input to the Fast Fourier Transform (FFT) and if there is the presence of periodic damage, spectral lines appear that identify the defect frequency. By knowing the geometry of the internal components, one can easily correlate the event frequency with a specific component. For example, knowing the size of the bearings and the number of rolling elements enables one to calculate the inner race and/or outer race frequency for a given operating speed.

News and Events

Product
Release Information

FAMOS Version 21

Released May 15, 2017

New
PEPSE Version 82

Release Date
November 3, 2017.

New Product

Cycle Isolation Monitoring

Training

PEPSE

February 13-16, 2018

September 11-14, 2018

PMAX

Watch for 2018 Schedule

News

Presentations at Scientech's 2017 Symposium are available. Click here.

Scientech papers presented in 2013 at EPRI are available.