What Is Vibration Analysis?
How does vibration analysis work?
Vibration analysis is the process of measuring the vibrations of a machine’s moving parts, those under stress and the machine as a whole. Collecting and comparing the information with previous results can give the earliest detection possible of where a problem may occur over time. The main advantage of vibration analysis is that it can be carried out while the machine is in normal operation and need not be just a part of routine planned maintenance.
Vibration analysis should be carried out on new machinery before it is put into operation. This is a chance to start with a clean sheet and to gather as much information as possible – this can be exhaustive and contain even the smallest detail, such as the manufacturer of different parts of the machine, even down to ball bearings. Every subsequent monitoring procedure is then compared to the readings taken.
Vibrations can vary from the simple to the complex. A single ball bearing, for example, may have a single vibration, whereas rotors and shafts may have vibrations from their component parts that all contribute to a more complex array of vibrations. These can be measured both alone and together by vibration analysis, giving a detailed picture of how the machinery is behaving at the time and how it is likely to behave in the future.
The ’signature vibration’ of a machine is obtained in three dimensions from various points; this is essential as some possible problems may be detectable in only one of its axes. Measurements can be taken at the machine’s normal operating speed, as well as at faster speeds to give a more accurate picture, as different parts of the machine will operate at different speeds.
What vibration analysis gives us, most importantly, is the frequency of all the vibrations in a machine, and helps to distinguish which are wanted and which are not.
Early Detection Using Vibration Analysis Is Best For Maintaining Effective Systems
Vibration analysis is acknowledged as the most effective method of detecting variations in the status of machine parts, in particular bearings. This analysis can be used either as part of a planned maintenance procedure or in condition-based monitoring. The second of these procedures is much more preferable, as possible faults are monitored and detected as early as possible, leading to as little repair and downtime as possible.
Bearings have their own unique, discernible vibrations, but are also subject to vibration from other parts of a machine. It is important to be able to measure their vibration both independently and as part of a larger operation. All parts of a machine are subject to friction during their working life and vibration analysis will pick up any noticeable defects resulting from friction at the earliest possible date.
When newly-installed, a machine will be balanced and checked before it is put into operation. Having its vibrations recorded at this first stage is vital when comparing the condition of the machine during subsequent maintenance. Excessive force or conditions that may lead to incorrect balancing can be detected and remedied before they lead to a major problem.
Vibration analysis can not only detect changes in the vibrations in parts of the machine or the equipment as a whole, but the effect of other machinery on site. Analysis can be taken not just on one machine, but at different points around the site. These testing results can give a clear indication of the overall health of the plant and trends in noticeable variation in vibrations.
CLENG engineers are trained to use a variety of state-of-the-art tools and decide which techniques to use to help them to collect most accurate and relevant readings, to give an accurate prediction for problems that are the most likely to occur.
How Vibration Analysis Can Reduce System Downtime
Vibration analysis is a vital part of condition monitoring, giving not only an overall picture of a machine but details about its component parts and how their condition is affecting others. The most welcome reason to make the most of vibration analysis is how it reduces down time.
For vibrations to be monitored, it is necessary for the machine to be running at normal speed, but it is also useful to check the vibrations when it is running at higher revolutions. For this reason, the machine can carry on producing while trained specialist engineers can measure exactly what is going on underneath.
Early detection of possible failure of a part is one of the main reasons for using condition-based monitoring over planned maintenance. If one part is predicted to be due to fail, it can be replaced alone. If the part’s failing is not detected early, then it may begin to affect other parts which themselves may need attention.
With early detection, scheduled repair can be arranged to fit with other down times at the plant. Less down time will obviously lead to less lost production time, but labour costs are also lower, with less replacements of components and fewer, hopefully no emergency call-outs.
Safety is another important aspect that is enhanced when using vibration analysis in advance of any problems occurring, helping to protect not only operators but anyone connected with the process, including customers for its products.
With less production time lost, this benefits to the overall health of the plant as a whole and inevitably leads to greater profits for the company and greater benefits for its employees. CLENG uses a holistic approach to maintenance, and this approach is reflected in the improvement to the overall health of its customers’ operations.
Vibration Analysis In Rotation Equipment
Rotating equipment – what problems can arise?
Every piece of machinery has rotating parts, from a child’s bicycle to the Mars Colonial Transporter. All of these are subject to wear as they carry out their function, so it is only natural that problems will occur over time.
In rotating motors, one of the most common causes of problems is degrading bearings. This can lead to overheating and variations in speed. These are unwanted and will only worsen if not addressed as soon as possible. Any important item of machinery will affect those around it, so all parts of new machinery are carefully analysed, even down to the smallest. This will include the identity and make-up of parts, even manufacturers of smaller components such as bearings.
These readings are invaluable to maintenance engineers who have a head start when diagnosing if they are armed with as much information as possible, giving the most suitable replacement parts to use where necessary.
Any rotating part is also liable to move out of alignment and this will lead again to increased unwanted vibrations. Regular vibration analysis will provide detailed readings of any alignment problems. Another symptom of unwelcome vibration is loosening of bolts, so these need to be checked regularly or could lead to a catastrophic, even fatal breakdown of the machine.
But before it is time to call in the experts, it is worth remembering that operators can also do much to prevent problems occurring in rotating equipment. such as monitoring lubrication levels and regular, thorough cleaning. This will not only help to reduce vibrations but is essential to enable thorough inspections. Operators will also be able to detect a change in vibrations in the machine, meaning it is time for a vibration analysis inspection. Overall care and monitoring is essential to prevent small problems growing worse.
Vibration in machinery is not necessarily a bad thing.
It will occur naturally whenever and wherever anything moves. Vibration allows us to hear sound waves and appreciate music. In machinery, a constant unchanging level of vibration is a sign that the equipment is running smoothly, so what vibration analysis allows us to detect is any sign that things aren’t running at optimum levels.
Monitoring vibration has been a constant diagnostic practice ever since machinery came into production. Using a rod against the machine to feel its vibrations, a stethoscope or even a highly-trained ear are all techniques that have been used to keep machinery running smoothly, for more than two hundred years. These days, we are fortunate to have the most up-to-date, sensitive equipment that allows technicians not only to detect, but to keep a constant record of a machine’s behaviour.
Any piece of equipment will naturally vibrate at its own rate. This can be detected, examined and logged for future reference, so that any deviation, however slight, will show up. Issues can then easily be located and attended to. Ongoing testing will give a history of the machine, so changes can be monitored over time. Highlighting the possibility of a future problem will allow for maintenance to be carried out before a problem occurs, and not after. This is essential in the constant battle against the dreaded enemy, down time.
Engineers at CLENG have access to the latest vibration analysis equipment, to monitor and log the behaviour of a piece of machinery. We keep up to speed with the latest developments in diagnostic tools, but our engineers have the edge when it comes to predicting accurately just how a machine is likely to behave in the future, both near and long-term.
There are now many technologies in the world of Vibration, but our engineer’s skill in being able to interpret its results has put CLENG at the forefront of machine analysis, predictive maintenance and the smooth running of all machinery. Machines rely on each other – they work as part of a chain, so CLENG ensures that the chain remains unbroken by using a full range of CM technologies with our holistic approach backed up by our unique Asset Health Reporting site.