Many processes are shut down on routine basis for visual inspection of the machinery, whether or not anything is amiss. Routine analysis of vibration allows maintenance engineers to extend running time between shutdowns.
Vibration and temperature are the most common parameters used for machinery protection. Of these, temperature has been used longer, probably because it was available first and was better understood than vibration analysis.
However, vibration may be the better measurement over temperature since it becomes apparent earlier and the multitude of frequencies and amplitudes that are present in the signal allow for a more detailed analysis.
Sources of vibration
Unbalanced rotating equipment, misalignment of machines, bent shafts, oil whip in journal or sleeve bearings, gearboxes and vehicle movement – amongst others – all have the potential to generate destructive vibrations.
How is vibration defined?
To accurately analyse a vibration problem, it is necessary to describe the vibration in a consistent and reliable manner. The two most important numerical descriptors of machine vibration are amplitude and frequency. Amplitude describes the severity of vibration and frequency describes the rate of oscillation. Together, amplitude and frequency provide a basis for identifying the root cause of vibration.
How is vibration measured?
A vibration sensor or a transducer is a device used to convert the energy of vibration into a voltage or current. It is normally used to measure machinery or structural vibrations. The most common vibration sensors include velocity, accelerometers and proximity probes. Each type has its own distinct advantages.
Velocity transducers
These units monitor vibrations in rotating machinery, they are economical, easy to install and have frequency range from 0,5 Hz to 10 kHz.
Accelerometers
Most commonly used in the industry, light, compact and rugged while also possessing a wide frequency range from 2 Hz to 60 kHz. They utilise the piezoelectric principle to convert mechanical motion into a voltage proportional to the acceleration caused by vibration.
Proximity probes (Eddy current transducers)
These are preferred for monitoring vibrations on rotating machinery equipped with journal bearings. Eddy current transducers provide measurements of shaft displacement or measurement of shaft relative to the bearing.
Why measure vibration?
Changes in the ambient levels of machine vibration provide early warning of costly equipment failure. Analyses of vibration patterns enable machines to be shut down before catastrophic failure occurs and assist in the diagnosis of the root cause; spare parts and maintenance activities can thus be scheduled in advance and costly downtime kept to a minimum.
Vibration monitoring in three axes ifm - South Africa
Sensors & Transducers
Machine vibrations are important indicators when it comes to assessing the current condition of a machine. ifm’s new and smart IO-Link vibration sensor helps to implement a simple and scalable condition monitoring approach using but a single device.
Read more...Optimise sludge treatment and reduce operational costs
Sensors & Transducers
The Endress+Hauser inline measuring devices, the Proline Teqwave MW 300 and the Proline Teqwave MW 500, determine the total solids content of wastewater directly through microwave transmission. This is considerably less time consuming than the process of determining total solids content in a laboratory.
Read more...Family of analysers for smart and efficient chlorine measurement ABB South Africa
Sensors & Transducers
ABB has launched ChloroStar, a family of sensors, transmitters and accessories for accurate and reliable chlorine measurement and analysis that enable users in the water, wastewater and other industries to control chlorine more efficiently, enhancing treatment and increasing process uptime.
Read more...Leading the way with Level 9 PDS implementation
Sensors & Transducers
Applying a Level 9 Proximity Detection System (PDS) to a mining operation is as much about changes in behaviour as it is about technical solutions, according to Pieter Wolfaardt from Apex, Booyco Electronics’ training partner of choice.
Read more...Enhanced automated weld inspection system
Sensors & Transducers
SmartRay is offering the release of new hardware for its weld inspection system, JOSY, delivering elevated performance and flexibility in the process.
Read more...Leaders in sensor technology Gail Norton Instrumentation
Sensors & Transducers
Photoelectric eyes have always needed perfect working conditions, but in the workplace there is no such thing. Steam, water, light and dirt interfere with most photoelectric eyes, but never with a Telco sensor.
Read more...Easy parameter setting of vision sensors ifm - South Africa
Sensors & Transducers
Contour verification and object inspection are two of the most important functionalities in industrial imaging. With the new O2D5xx series, ifm now offers a solution that perfectly masters both functionalities
Read more...Keeping a close eye on product quality and purity Endress+Hauser South Africa
Sensors & Transducers
Colour measurements are necessary in many processes to avoid product losses and ensure safe production and batching. The Memosens Wave CKI50 process spectrometer from Endress+Hauser is a compact, robust and process-friendly device allowing quality, batching and phase checks to be performed by a single instrument for the entire visible colour spectrum.
Read more...The sensory reaction of building management systems Schneider Electric South Africa
Sensors & Transducers
Today’s building management systems (BMS) cannot function properly without sensors. This is so critical that if sensors start failing, they can become ‘blind’.
Read more...Advanced sensor technology to reduce vehicle fatalities Senseca
Sensors & Transducers
Measurement technology plays a critical role across a range of industries. This is especially true when supplying highly accurate and reliable data for road management entities that assist drivers of vehicles experiencing hazardous weather conditions.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version