MRO Magazine

How alignment and condition monitoring extend motor life

Alignment is a critical component of extending motor life. Learn why you should pair alignment with a condition monitoring program.


Machinery and Equipment Maintenance

February 11, 2022
By Eric Elder

Industries

Photo: Fluke.

When machinery is misaligned, it can cause downtime, slow down production, increase energy costs, and damage machinery. Misaligned machines can also run hot as a result of consuming excess energy. This means not only higher energy bills, but also potential lubrication breakdown and safety concerns. Proper shaft alignment is especially important for rotating equipment operated at high speeds.

Misalignment happens when the centerlines of the driver and the driven equipment shafts are not colinear, or in a straight line with one another. Correct shaft alignment increases the operating lifespan of machinery. A properly aligned shaft provides the most efficient power transmission from a motor to the driven equipment.

By shifting alignment from being an afterthought to a regular occurrence, you not only extend motor life — you free up your maintenance team to focus their time on true priorities. When equipment is properly aligned, there’s less need for repairs and replacements, because components last longer. But alignment isn’t a one-time thing. To understand how alignment changes over time, you need to collect and analyze condition monitoring data using hand-held tools and sensors.

Consequences of misalignment
Poorly aligned machinery requires more replacement parts than properly aligned machinery, so it’s more expensive and time-consuming to maintain — and diverts parts and labour from other needs. For example, misalignment can cause seals to fail. And when a seal fails, it can cause fluid leaks and harm other machine components. Seals themselves can also be expensive to replace.

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Misalignment is also a leading cause of excessive vibration. It can also cause premature failures in bearings, couplings, or shafts. These failures can also go on to damage other components or lead to downtime.

Flexible couplings can tolerate more misalignment than rigid couplings, but they still have certain requirements and tolerance limits. Using flexible couplings is not a substitute for proper alignment, and improper coupling choices can cause failures. A coupling that is too tolerant of misalignment for the application, for example, can cause increased vibration or unbalanced rotation.

Motors face three main types of misalignment: angular misalignment, offset/parallel misalignment, and combination misalignment (which is when a motor shaft experiences both angular and parallel misalignment at the
same time).

Achieving and maintaining precision alignment
Attention to a machine’s alignment should not end with installation. New equipment should be checked for changes in alignment after several months in case of settling, and the most production-critical equipment should be checked on a regular cadence. Alignment data can also be captured whenever equipment is down for maintenance. Over time, this data can provide insights about ways that alignment can be improved.

For example, it’s crucial to know the correct operating temperatures of a machine’s components and record them during normal operation. Heat can cause materials to expand and change a machine’s alignment. Different materials expand at different rates, as well as at different thresholds. Also, keep in mind that OEM data can sometimes differ from real-world operating conditions. Once you have an established baseline of temperatures, any deviations will stand out.

Alignment is not a fixed, static state, and misalignment can be caused by many different factors or conditions. A machine’s alignment can change when the machine experiences changes in temperature, pressure, load, or vibration.

Condition monitoring can detect misalignment problems before they lead to failures and downtime, with vibration monitoring being especially effective. A thermal imager can spot a coupling that is too hot, but that won’t reveal the cause. Vibration data offers a fuller picture of asset health, with certain types and locations of vibration indicating alignment issues.

There are vibration monitoring tools available for a wide range of budgets and applications, whether you want a handheld tool for collecting basic data during route-based maintenance, vibration sensors for around-the-clock, in-depth condition monitoring of critical assets, or something in between.

Many successful maintenance teams use condition monitoring to collect asset data in real time. Every machine will require intervention at some point — usage and wear eventually cause failures — but condition monitoring can provide the insights you need to identify potential failures before they happen. The frequency and detail of the monitoring can be tailored to the criticality of the machine.

Using condition monitoring sensors and analysis software
Condition monitoring is a cost-effective way to track asset health in real time. Sensors and software make it possible to assess the condition of many machines, around the clock, without requiring someone on site taking measurements. When you and your team know the condition of your machines, you can reduce or avoid failures and downtime.

Trending machine condition over time, and using software to analyze the data, gives your team the insights and knowledge they need to plan and prioritize their actions most effectively. Vibration monitoring is an effective way to monitor assets, from the most critical to the most often overlooked.

With a full picture of asset health, you can more effectively determine which maintenance actions need to happen and when. Planning maintenance this way, rather than relying on a calendar or reacting to failures after the fact, increases uptime while reducing spending. Replacing parts before their true end of life uses labour and materials that could be used in other ways. Calendar-based maintenance doesn’t neatly or necessarily correspond to actual asset condition, and it doesn’t help teams spot quickly progressing problems. Significant failures can still happen even with regular preventive maintenance.

When maintenance teams are in a reactive mode and responding to failures, rather than keeping machinery in peak operating condition, reliability, efficiency, and production are all hampered. Using real-time knowledge of asset condition enables teams to use the full lifespan of machine components and plan repairs in advance. Repairs can be made before extensive damage occurs, meaning unplanned downtime occurs much less often.

Analysis software makes it possible for even small teams or novice technicians to interpret asset data. Some software even offers teams the ability to customize operational thresholds for assets, and to send notifications and alarms whenever an asset operates outside of those defined limits. From there, the team can intervene as necessary and diagnose the problem.

Taking a proactive maintenance approach
Aligning a machine is not a one-time event. To understand how the alignment of your machines change over time, you need to collect and analyze machine condition data. That real-time asset data makes it possible for teams to identify and resolve potential problems before they escalate. It also makes your team safer.

Not only does condition monitoring reduce the number of times technicians need to access hard-to-reach or hazardous areas as part of route-based maintenance, but planned repairs are much safer than emergency corrective repairs. With a combination of condition monitoring and software, your team can remotely monitor assets, accessing real-time measurements from a desktop computer or a smartphone. Having an overall facility view of asset health helps teams plan and prioritize. Labour hours are often a limited resource for maintenance teams, and using time and effort wisely drives productivity and safety.

Making data-driven decisions improves operations — but is only possible when teams have the right data and know what to do with it. Maintenance teams that don’t pay attention to machine alignment are operating with a blind spot.

Keeping your machinery properly aligned has numerous benefits. It reduces downtime, decreases your energy bills, extends the life of your equipment, and allows your maintenance team to optimize their time and effort. In today’s competitive landscape, the costs of wasted time, energy, parts, and materials add up quickly. Availability and reliability are key. Being proactive about alignment can mean more uptime with less spending. MRO
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Eric Elder is Service Manager for the Americas region at Prüftechnik (www.pruftechnik.com), part of the Fluke Reliability family. He holds a Bachelor of Science Degree in aviation maintenance from the Pennsylvania College of Technology. Eric has more than 10 years of experience in industrial maintenance, including as an alignment specialist and is a Certified Reliability Leader (CRL) and Vibration Analyst, Category II (ISO 18436.2).