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30-second summary

  • Common misalignments are usual and can happen to machines in a variety of ways.
  • Left alone misalignment can reduce the longevity of bearings, shafts, seals, and even couplings.
  • Misalignment is the root cause of most machine breakdowns: bearing failures, and damaged seals, shafts, and couplings.
  • It is widely believed that 50% of machine failures are due to misalignment.
  • Treating the misalignment early on, whether by a soft-foot correction, dial indicator alterations or a full-fledged laser alignment, will help to prevent total machine failure.
  • The basic rule of thumb is, machines that are precision aligned will function for a longer period and costs less to run.

How does misalignment occur?

Common misalignments are the result of two rotating shafts not parallel to one another, either by a slightly offset or angled gap at the coupling. However, sometimes in most real-life situations it is both, which is called a compound misalignment. There are several causes for misalignment:

  • Pipe strain
  • Thermal expansion
  • Human error
  • Wear causing sheave to deform
  • Baseplate settles irregular to form a ‘soft-footing’
  • Inaccurate assembly of components, such as motors and pumps.

The primary point to remember is that any unsteady motion or movement to shaft centrelines that goes against the intended motion of the machine can cause bearing or couplings to be stressed, and the seals to undergo damage in need of immediate repair.

The Laser Alignment course is ideal if want to improve your knowledge of shaft alignment. This is one-or-two-day Onsite course. It includes a walk-through of the alignment benefits and methods, as well as hands-on exercises – your understanding and appreciation of shaft alignment will skyrocket!

Five types of common misalignment

1. Parallel misalignment

This occurs when two shafts (or sheaves) do not exist on a parallel plane—while their centrelines may be parallel to one another, the actual centreline is offset.

2. Horizontal angle misalignment

This occurs when the angle of one shaft is different to the angle of the other on a horizontal plane.

3. Vertical angle misalignment

This occurs when the angle of one shaft is different to the angle of the other on a vertical plane.

4. Horizontal angled and offset misalignment

This is a compound misalignment that occurs when one shaft is both offset and angled differently than the other shaft along a horizontal plane.

5. Vertical angled and offset misalignment

This is a compound misalignment that occurs when one shaft is both offset and angled differently than the other shaft along a vertical plane.

How best to recognise and detect common misalignment?

While it is important to understand the root causes of misalignment and the most basic forms in which it occurs, the most important thing to know is how to recognize misalignment before it reduces the life of bearings, seals, shafts and couplings. As mentioned, a properly precision aligned machine will run more effectively and last longer, therefore the detection of misalignment is often best ascribed as a form of preventative maintenance, rather than a reactive resolution.

The AMS 2140 Machinery Health Analyser coupled with the AMS 8240 sensALIGN laser fixtures makes for a powerful combo-package that can help rectify misalignment issues easily.

How to detect shaft speed using a SpeedVue laser

With that in mind, there are five primary methods used to detect common misalignment:

1. Misalignment detection technique: Thermography

Becoming increasingly popular for its ability to recognise misalignment easily in machines, especially in belt drive applications. A clear indication of misalignment is an increase in friction as the offset or angular shafts are likely pulling against one another ever so slightly more. This, in turn, increases the temperature of the machine at the problem area.

The job of thermal-imagery, then, is to measure these hot-spots and determine exactly where the problem is occurring or beginning to occur. Thermography is a secondary indicator as when there is an increase in temperature damage is being caused mechanically.

2. Misalignment detection technique: Vibration analysis

Vibration analysis is effective at assessing the micro-vibrations of a machine and noting when it approaches or exceeds acceptable parameters. These minute observations can be used proactively, just as thermography, to recognise an issue with misalignment and stop it before the bearings or belts wear down to catastrophic levels. As the variables of those micro-vibration increases can vary by degree and complexity, often a result of some things more than only misalignment, imbalance or looseness overtime, the analysis is conducted using Accelerometers and correct sampling for the expected failure mode predictor. An important aspect of vibration analysis is phase analysis used to diagnose and pinpoint the type of misalignment early on. All these tools of measure help the analyst to determine exactly what is causing the disruption or how to prevent it escalating.

3. Misalignment detection technique: Oil analysis

One of the more complicated measures to determine common misalignment, oil analysis is a process by which an analyst can measure misalignment through the general wear-and-tear on contaminants in oil of the machine. While specialists are often required to conduct a proper oil analysis, its results often are not as effective for preventative maintenance with misalignment.

4. Misalignment detection technique: Laser shaft analysis

Likely the most common of all forms of misalignment checks, laser shaft alignment systems can accurately calculate the degree to which a coupling may be offset and allows for an accurate measure of remedy to get it along an even plane. Precision Laser alignment results can be greatly affected by operator experience and training.

5. Misalignment detection technique: Motion Amplification

This is the easiest of user’s interfaces to visually diagnose misalignment and also to visually see the rout cause of the misalignment. You do not need to be experienced or an engineer to view a motion amplification video so see there is misalignment.

Recent example: Iris M™ with the new Tach Sync

Pump base problem visualised

Our experienced vibration analysts can help recognise and fix common misalignment for your machines.

How to correct common misalignments?

The good news is that the hardest part of misalignment is determining where it exists for how long it has existed. The solutions to misalignment vary from simple to complex. Often it can be replacing bearings, belts, or couplings and other times those pieces are in good enough shape that all that is needed is a ‘soft-footed’ correction or slight alignment correction. If a misalignment has gone on for too long unnoticed, it might be the reason that the machine is beyond repair. On the other hand, preventative maintenance and scheduled misalignment analysis can help to ensure machine’s longevity, improve energy efficiency, maximize output, and overall save money by mitigating problems before they move beyond repair.

Common misalignment issues are a topic on the Vibration Analysis CAT-II course. This is ideal for those who been performing vibration analysis for more than twelve months and have a good understanding of the fundamentals.

Gallery images

Precision Shaft Alignment is a learning topic within the iLearnReliability Condition Monitoring software. It is intended for anyone wanting to further their understanding of monitoring, diagnostics and precision maintenance to support increased plant reliability.

If you have any questions about common misalignment in maintenance and how Reliability Maintenance Solutions can help you, please feel free to contact us or leave a comment below.

FAQs on common misalignments

Of the different methods available, Laser alignment is the most accurate method. Laser alignment uses lasers to determine the exact shaft position but is very dependent on user experience in the process of precision alignment.

Measuring different sections along the horizontal and vertical planes will help determine shaft misalignment and whether the misalignment is angular, parallel, or often both. Phase analysis offers the most precises diagnose of misalignment.

When installing bearings be aware that common misalignment can often occur. Ensure that the housing is rigid to best ensure support for the bearing.


30-Second Summary

  • Wear and tear, Unbalance, looseness and misalignment are the most commonly found vibration issues in machines.
  • Precision balancing and alignment practices will help minimise forces acting on a machine’s bearings and shaft seals, thereby resulting in improved reliability of these key component parts
  • Timely detection of machine vibrations can help avoid downtime and enhance the lifespan of machines.

Machine vibration problems reviewed

When looking at machine vibrations it is always necessary to be able to distinguish between normal operations and emerging problems.

Vibration can be symptomatic of a problem, or it can be the cause of a problem. There are times when the machine isn’t physically vibrating and there is a problem. In general, most systems are designed to avoid vibration as opposed to creating it. (Excluding shakers and screens of course!)

Vibration Analysis Courses are designed for reliability engineers, PdM program managers, and other maintenance staff who would like to understand condition monitoring with a focus on vibration analysis.

4 common machine vibration problems

Vibrating machinery, left unchecked, can speed up the deterioration rate of parts or cause damage to the system that may require key components of a machine to be replaced.  There are quite a few causes for why machinery may start vibrating, here we are going to look at the four most common reasons.

  • Wear

With rotating components like roller or ball bearings, gears, or drive belts, when these components start to show signs of wear the machine vibration vibration patterns and levels change, mostly increasing in vibration.

For example, if a roller bearing race becomes pitted, then the bearing rollers will generate impacting and frictional machine vibration. This occurs as the rolling elements travel over the section of pitted race. Other examples of wear causing vibration include: a drive belt breaking down, or a heavily worn or chipped gear tooth. These both generate a different increase and pattern change in the vibration signature.

  • Unbalance

If a rotating component has what is known as a heavy spot this can cause machine vibration, this increases exponentially with speed. Unbalance is when the shafts geometric centreline and mass centreline do not coincide. The reason for this is because the heavy spot will force the mass centreline off the geometric centreline.

Unbalance can be caused by a few different things, such as:

  • maintenance issues: missing balance weights or dirty or deformed fan blades.
  • manufacturing defects including casting flaws or machining errors.

The effects of an unbalance will become greater as a machine’s speed increases. The biggest concern with unbalance is that it can cause unnecessary machine vibration and drastically reduce the operational life of bearings.

  • Looseness

Looseness can be Rotating or Mechanically generated.

There are three types of Mechanical looseness to consider: Rotating looseness, Structural looseness (foundation flexibility) and Non-rotating looseness. Rotating looseness can occur due to wear in a bearing.

The problem with looseness is that irrespective of what caused it, looseness can cause damage such as: fatigue and wear in equipment mounts and further bearing wear. It can become very dangerous and destructive if a vibrating component is either loosely attached to its mounts, or has loose bearings.

Our experienced machine vibration analysts deliver services for a wide range of industries and applications, including: routine machinery surveys, commissioning, troubleshooting, verification, and database setup and support.

  • Misalignment/shaft runout

A common cause of machine vibration is when the machine shafts that are out of line. Misalignment is a root cause of many machine breakdowns, bearing failures, and damaged seals, shafts and couplings. In fact, it is widely believed that over 50% of machine failures are due to misalignment.

Misalignment does not have one single cause but can be a combination of causes. It can happen:

  • By developing over time (wear)
  • During the assembly process
  • Not considering thermal expansion during the alignment process
  • Not being reassembled properly after maintenance
  • Because of shifting components (structural issues)

Not practicing precision alignment will cause premature wear and tear of components, increase unscheduled downtime, increase maintenance (asset life costs) costs due to unexpected repairs—or more expensive, replacement of parts.

RMS provide Motion Amplification Services for a wide range of Industries and applications, including: vibration verification, commissioning, troubleshooting, R&D and root cause analysis.

Why it’s necessary to treat for vibration problems

As we have already mentioned, vibration can create problems that are both time consuming and expensive. For example: vibration consumes excess power, forces equipment to be taken out of service for unscheduled downtime, and expedited machine wear increasing overall asset life costs.

There are also secondary safety issues to consider as well as reduced operational uptime.

Measuring and analysing vibration can provide the asset owners with an indication of a machine’s health condition, and hence the reliability. When this data is analysed correctly it can help with preventive and reactive maintenance actions.

It can improve preventive maintenance by enabling the maintenance team stay ahead of potential problems. It can help with corrective maintenance to ensure that everything which needs repairing—or replacing—is done the first time so there are no unpleasant surprises later on.

Technicians need to be able to understand the difference between abnormal and normal vibration in machine components. With this understanding and the right tools, a technician can reliably, effectively, and quickly find the machine vibration-related issue. And then determine whether or not the component(s) can be repaired, serviced, or if they need to be replaced.

Flue Gas Fan Bearing 2

Corrective methods for machine vibration problems

When it comes to machine vibration problems, the good news is that practically all issues can be corrected in place. That is, of course, provided the vibration-related issues are found early enough.

There are few ways to correctly treat machine vibration problems, these include:

  • Precision balancing
  • Bearing replacement
  • Identifying any additional bad parts and having them sourced then replaced.
  • Precision Alignment
  • Precision Lubrication. That is, ensuring the correct lubricant win the correct volume at the correct time.
  • Dissemble, inspect visually, clean, and then reassemble, this can help to fix some of the more elusive problems. (Be aware of introducing new defects due to human error on intrusive maintenance like this.)
  • Stiffening and mass loading to reduce measured vibration. This should lower motion, however, it will increase local stresses on the bearings if the cause of the vibration is not eliminated. And this will cause bearings to wear at a faster rate.

On a final note, some machines do have excessive vibrating. In these case, and where the machine function is still being fulfilled and there is no deterioration, it may not be worth doing anything. That is, provided that the machine is carrying out its primary function with no apparent anomalies. If the vibration amplitude is stable, then in most cases it’s usually safe for the machine to continue operating. The advantage of this is that it will avoid additional downtime and the unnecessary cost of repairs.

As long as you are monitoring and assessing your machinery with vibration analysis, then you should be able to plan, operate your machines for longer with less wear and tear, as well as reducing the risk of machine failure.

Through active listening we get to understand the problem before talking about solutions. When the problem is understood we recommend possible ways to improve condition through the use of vibration analysis. The AMS 2140 from Emerson is once such technical solution.


If you have any questions about the role of vibration analysis in maintenance and how Reliability Maintenance Solutions can help you, please feel free to contact us, or leave a comment below.

FAQs

There are quite a few causes for why machinery may start vibrating, there are four most common reasons: Wear, Unbalance, Looseness, Misalignment/shaft runout.

Technicians need to be able to understand the difference between abnormal and normal vibration in machine components. With this understanding and the right tools, a technician can reliably, effectively, and quickly find the vibration-related issue.

Precision balancing, Bearing replacement, Precision Alignment, Precision Lubrication, Dissemble – reassemble, Stiffening and mass loading.


30-Second Summary

  • An infrared camera is one of the most primitive yet trusted methods for identifying an electrical connection or component problem.
  • Misalignment, steam/water leaks, bent shafts, and moisture are some of the issues that can be detected using thermographic analysis.
  • You can learn more about thermographic analysis by enrolling on a CAT I Vibration Analysis course.

Infrared Thermal Imaging is useful across many industrial sectors

Hi! I’m Craig Smith, a Reliability Engineer at RMS. Over the past few years I’ve been using Infrared Thermal Imaging technology to great affect, helping customers diagnose and repair maintenance issues with higher degrees of accuracy and speed.

This article is based on a planned electrical maintenance survey of panels and distribution boards looking for any irregularities. This consists of cables, cable connections, breakers, inverters and control boards.

Our Infrared Thermography service is a predictive maintenance inspection technique that is widely-recognized and an effective non-destructive (NDT) testing tool used often to check electrical and mechanical systems, buildings, roofs and facilities.

Traditional methods of detection

The traditional method for identifying an electrical connection or component problem is the use of an infrared camera when it is under load. However, there is misunderstanding about how to establish the condition of the connection once a thermal anomaly has been found.

Historical methods of Infrared Thermal Imaging have applied the use of temperature, or temperature rise, using the infrared camera, as an indicator of the defect severity. Infrared, however, only identifies surface temperature rather than internal interface temperature.

The value of Thermography is being able to identify that a thermal anomaly exists

While thermography can identify a connection problem through the thermal pattern, the connector surface temperature can be a poor indicator of the nature of the problem or its severity.

How do Thermal Imaging cameras work?

The A0404B1 Infrared Tachometer is recommended for indoor/outdoor use. When used with Emerson’s Machinery Health Analyzers, the phototachs provide a tach reference signal for applications that include measurement of turning speed, synchronous time averaging, machinery balancing, phase tracking, and coastdown/startup analysis.

Where can Infrared help technicians?

Now that we’ve briefly explained the importance of Infrared Thermal Imaging, let’s look at exactly how thermography helps in maintenance.

Key components that thermographic analysis can detect problems with include, but not limited to:

  • Misalignment
  • Bearing health
  • Steam/Water Leaks
  • Turbine machinery
  • Bent shafts
  • Solar panels
  • Moisture
  • Loose bolts, mounts, fasteners, etc.
  • Electrical issues
  • Process flow issues

Top tips when taking a thermal image

  • Understand the surrounding parameters:
    • shooting an image with sunlight or a reflective background (inside panels) will give you bad data
    • also if you are in a panel room and the AC is on
  • Stand at 45* to the object of interest and use multiple angles if possible
  • Adjusting the Emmissivity and Reflected temperature accordingly is a must, or you will get bad data
  • Using a known source of black body:
    • carry electricians’ tape with you and put a piece on the object if safe to do so
  • Don’t ignore small temperature differences:
    • if you are looking at two objects close together one may be quite a lot hotter than it appears on the image
  • Focus on the object and thermally tune the camera to suit using the temperature adjustment

Problem awareness

  • Connections problems occur when fitting lock screws that are under-torqued or Over-torqued
  • Incorrect cable sizing for breaker etc, wrong size lug connections or not lug at all
  • Cable insulation not cut back enough
  • Poor soldered joints.
  • Excessive vibration in the area,
  • Process patterns with stop start or VSD motors
  • Environment issues such as heat or steam, corrosives
  • Always have a good scope of the area you are working in and a good visual of what you are looking at

Recent images explained

The CAT I Vibration Analysis course includes a topic on Thermography. The course is designed for reliability engineers, PdM program managers, and other maintenance staff who would like to understand condition monitoring with a core focus on vibration analysis.

If you have any questions about the role of thermal imaging in maintenance and how Reliability Maintenance Solutions can help you, please feel free to contact us, or leave a comment below.

FAQs

Historical methods of Infrared Thermal Imaging have applied the use of temperature, or temperature rise, using the infrared camera, as an indicator of the defect severity. Infrared, however, only identifies surface temperature rather than internal interface temperature.

Key components that thermographic analysis can detect problems with include, but not limited to: Misalignment, Bearing health, Steam/Water Leaks, Turbine machinery, Bent shafts, Solar panels, Moisture, Loose bolts, mounts, fasteners, etc., Electrical issues, Process flow issues.

Don’t ignore small temperature differences. If you are looking at two objects close together one may be quite a lot hotter than it appears on the image.


30-Second Summary

  • Vibration analysis allows you to detect early signs of machine failure/deterioration. 
  • A trained vibration analyst can easily understand the basics of vibration analysis as well as the failure modes of the equipment.
  • Predictive maintenance helps in preplanning all maintenance tasks as well as any unavoidable downtime.
  • Vibration data acquired from reactive maintenance can help replace or repair the parts which are exhibiting signs of wear and tear.

Vibration Analysis in Maintenance

Can your technicians make the replace-or-repair decision?

If you engage in maintenance practices, you will want to ensure your technicians can make the replace-or-repair decision before complete system failure of key components takes place. The easiest way to manage this risk is with vibration analysis.

Vibration analysis allows you to detect early signs of machine failure/deterioration. This allows your technicians to replace or repair machinery before catastrophic system functional failure takes place. Read more