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When dealing with a gearbox that has 3 feet,  there are two possibilities:

a) If the feet are located under the shaft and bearing housings,  view the gearbox as a normal 4-foot machine. This will give you inboard and outboard corrections for the feet. The end that has the 2 feet should be corrected evenly, and the 3rd foot should be corrected as per the screen.

b) If the feet are on the sides of the gearbox, or NOT under that shaft or bearing housings, then configure the gearbox as a 6-foot machine. This will give you corrections for the inboard, middle and outboard feet. Correct accordingly at each foot.

In any alignment situation,  one of the most basic principles is rise over run. Think of it as a change in offset over a distance. It is also a way to quantify angles without using degrees. When the laser system measures “angularity”, it expresses it as rise over run, or a change in offset over a distance. This information, along with the dimensions that the user enters is what the system uses to calculate corrections at the feet. That is why it is very important that laser measurements are repeatable and that all dimensions should be accurate to within 1/8 inch. The sensor to coupling dimension is the most critical of these. If the laser measurements are good but the dimensions for the feet are not, any corrections the computer calculates will not work due to the fact that they are “applied” to a different location, not at the actual foot location. If you are making the corrections that the computer says to and your alignment is still off, double check your dimensions.

Many facilities have placed overall vibration data collection devices in the hands of their operators.  The goal is to give the operators and production a tool to help identify equipment problems and the severity of those problems.

The intent of this effort is very good.  However,  the true value of this effort is usually not understood.
First,  generic overall vibration levels can be quite dangerous if not fully understood. Secondly, the actual value of having operators collect vibration data is not usually taken advantage of fully.

Overall vibration levels require the same amount of time for data collection as is required to collect very detailed vibration information on the equipment.  Therefore, the operator should actually collect the overall vibration levels they need while simultaneously collecting detailed information for the vibration analyst to review.  What happens if the operator collects an overall vibration level on a machine and some problem is suspected?  The facility has to invest time and effort for an analyst to revisit the machine and collect enough vibration data to actually verify and analyze the problem.  This means that additional labor is required or the results are diminished.  With the correct vibration hardware, the operator can easily collect the overall vibration values they need as well as the detailed information the analyst needs.  This saves time and money.  What if the activity occurs after hours?  The detailed data collected by the operator could be remotely passed on to the analyst for detailed evaluation.  This saves time and greatly improves the response time from employees and the technologies.   Operators could be used to easily and routinely collect vibration data on much of the equipment for analysis by the vibration group.  This would allow greater equipment coverage by the vibration analysis program, allow the analyst to focus on analysis, and spend less time collecting data.

To summarize, having the operator collect vibration data can be of great value if done the correct way, otherwise, the process can provide inaccurate information and reduced benefits.

Many plants have routine morning and weekly meetings to discuss equipment issues or upcoming repairs that could affect production or maintenance activities in the facility.  Are your condition monitoring (CM) and reliability efforts represented in these meetings?  Failure to have representation of your CM and reliability efforts in these meetings means that important information will not be conveyed to the individuals in the plant that need it most.

Your CM Manager or Reliability Engineer may have critical information to share about the health of the equipment being discussed in these meetings.  Additionally,  they need to be fully aware of what is happening in the facility and how their efforts may be affected.

Setting the proper LOR is essential to be able to separate closely spaced defect frequencies.  An example would be a pump with 5 vanes that could generate a “Vane Pass” frequency equal to the number of vanes,  or 5 times rotational speed; if the impeller end of the pump had an SKF 7301BEP bearing, it could have an inner race defect frequency of 4.99 times running speed.  This combination would require a relatively high resolution or LOR in order to have enough detail to separate the defect frequencies of each defect.

Overall values are the most common measurements and calculations used in vibration analysis. The purpose of this measurement and calculation is to identify changes in the condition of the equipment being measured.

Overall measurements are an important tool for the vibration analyst. However,  generic overall values can actually be deceptive if their limitations are not fully understood. Typically, overall vibration values are measured and a calculation based upon the entire frequency range is measured with the vibration data collector.

It is possible for certain frequencies to increase while other frequencies decrease. This is important because these changes are indications of specific machine conditions. The overall value could actually decrease or change very little and give a false indication of the machine’s health.

Band alarms and band analysis is the best vibration method to indicate changes in the condition of your equipment. Specific bands can be easily created, measured, and trended around the specific failure modes in the equipment such as bearings, misalignment, unbalance, and many more. This type of information can alert you much more accurately of failure conditions in your equipment versus generic overall measurements and calculations.

When machines are set in place,  aligned,  and buttoned down, it becomes too easy to forget about the gear couplings that may be used to transmit power between the machines. Gear couplings are tough workhorses that perform well in many applications because they operate quietly and efficiently. Since they are so reliable, we tend to take them for granted, forgetting about them unless trouble develops. Many times problems do occur simply because of neglect. Faults can usually be eliminated by keeping the shafts properly aligned and ensuring that the coupling lubricant is in good condition. Remember the old adage, “The right time to put in new lubricant is while the old lubricant is still good”. Open, inspect, and re-lubricate gear couplings every six months. If they operate in harsh conditions such as high ambient temperatures, they may need to be re-lubricated more frequently.  On opening the coupling, a close inspection of the lubricant will tell if the re-lubrication interval is too long. Adjust the interval accordingly, and be sure to use a lubricant specified for gear couplings. Also, make sure you do not over-lubricate. Pumping away with the grease gun until the lubricant oozes out past the containment o-ring is just as harmful as having too little lubricant. Finally, it is imperative that the lubricant fits the application and operating environment.

Information Technology (IT) is a critical business function and is involved in almost every job function within a company. IT departments and their employees are often viewed as making our jobs more difficult or impossible to complete. Why does this happen? IT departments have the responsibility to provide tools (computers,  software, systems, etc.) that create and manage critical business information. The responsibility to maintain, secure, and store this information falls upon them as well. They have to do this based on the standards set forth by the company.

If your company is about to implement a vibration analysis program or any other condition monitoring technology do not wait until the selection process has been completed to notify and involve your IT department. This could be creating a disaster situation between your department and IT within your company. It is critical to involve your IT department from the start of the selection process. This will help ensure that security requirements, computer requirements, and other critical things are taken into consideration before conflicts are created. You may actually find that your IT department can help you in your decision process, while avoiding conflict, saving time and money. Make IT an ally instead of an enemy!

One of the most overlooked features of a good vibration data collector is the ability to enter important process information such as temperatures,  pressures,  equipment lubrication levels, equipment speed, and much more.

Documentation of process data is important for your production department. This information is important to the Condition Monitoring (CM) Analyst as well.  Changes in process data may explain why the vibration amplitude levels or other CM conditions have changed.

Many facilities struggle with the ability to record and store process-related data. A good vibration data collector will have the ability to record and store this type of information.  In fact, routes can be created for operators to guide them through the routine acquisition of this information. Vibration data can be acquired by the operators as well. This could provide additional value-added time in your facility.

This data can be easily stored to meet the documentation requirements of your facility and trended to provide increased analysis opportunities that may otherwise go overlooked.

Our training partners at Pioneer Engineering have created a few tips your organization can implement aimed at cutting costs without sacrificing quality and productivity.

Tip #1: Establish a Reliability Centered Maintenance Program

• A well-established Reliability Centered Maintenance Program helps identify correct maintenance tasks to increase the reliability of the assets and cut costs by eliminating unnecessary PM tasks.
• Reliability Centered Maintenance Programs assist in clarifying maintenance responsibility and prevent costly unplanned downtime.

Tip #2: Perform a Criticality Assessment of all Assets

• Criticality Assessments will determine which components are critical to an operation’s efficiency and should receive the focus.
• Criticality Assessments quantify safety, environmental, operation, and repair cost consequences in the event of a functional failure.
• Perform Criticality Assessments on your spare inventory. Do you have the correct spares and quantity of spares in stock? Do you have unnecessary spares in stock that take up warehouse space and tie up capital that could be used elsewhere?

Tip #3: Avoid Costly Repairs by Analyzing Vibration Data on a Consistent Basis

• The consistent analysis allows the ability to monitor trends and detect problems before catastrophic failure occurs.
• Consistent analysis and trending allow flexibility in scheduling maintenance and reduced maintenance costs by preventing unscheduled downtime.

Tip #4: Avoid Fixing Repeat Offenders by Completion of Root Cause Failure Analysis

• Root Cause Failure Analysis will determine the underlying problem causing the failure to determine the best course of action
• Many failures are caused by operational issues instead of equipment or maintenance issues. A minor process adjustment may increase reliability and reduce costs.

Tip #5: Ask Questions

• Vibration analysis and other PdM technologies can help identify a potential issue but sometimes can be difficult to understand. Do not be afraid to seek expert guidance when potential issues are identified.

Need help improving and/or establishing a maintenance program in your company? Don’t hesitate to ask us how. We are here to help.

Thanks to the entire PIONEER ENGINEERING team for allowing us to share this article with you.

Maintenance departments periodically schedule maintenance checks on their belt- or chain-driven equipment in order to confirm that a good alignment exists between the pulleys or sprockets, especially if evidence of premature wear on the belts or sprocket teeth is detected.

For this task a Dotline Laser, Sheavemaster or Sheavemaster Greenline laser pulley alignment tool is ideal. It indicates misalignment in all three degrees of freedom (axial offset, horizontal angularity, and twist angle) instantly.

Always mount your laser pulley alignment tool on the smaller pulley and the targets on the larger one, for maximum resolution. Ensure that the mounting surfaces (pulley faces) are free of dirt or rust, and don’t forget to verify the proper tension of the belts (or chains) after the alignment.

Download Belt & Chain Storage Best Practices

A strobe lights is an inexpensive tool that every vibration analyst should have. Typically, strobes are used to determine the operational speed of equipment. However, a strobe can be used for many other troubleshooting activities. For example, coupling inspections can be completed to identify wear or other issues. The strobe can be set to a specific frequency to identify the source of an issue revealed by vibration analysis. Many other troubleshooting tasks can be easily completed using a strobe. Do not overlook the value this device offers.

The safety strap which is included with the analyzer should be checked for condition prior to each use. Most safety straps use Velcro and the Velcro is there for your safety. The strap is designed to separate to prevent injury should your cables become tangled in the rotating shaft or some other moving part of the machine.

Replace the straps if the Velcro becomes dirty or no longer holds. Never glue, bolt, staple, or otherwise permanently affix a strap to the analyzer, because this could prevent the strap from functioning correctly and result in serious injury to you or a coworker.

Soft Foot has often been noted as the most inexact science portion of Shaft Alignment. Historically, when people think of Soft Foot, they often want to neglect, ignore, or otherwise do everything possible to not deal with it. This is one of the traps that leads down the path of bad habits, bad alignments, and more problems down the line.
Shaft alignment can be thought of as two things: 1) Aligning the couplings and 2) Checking for and correcting Soft Foot. Soft Foot, in fact, plays so much of a role in shaft alignment, that if one were to analyze the 6-Step Alignment Procedure below, one can see that Soft Foot actually appears in 3 out of the 6 steps. Therefore, Soft Foot can be thought of as half the alignment job.

Overall Alignment Procedure

1. Pre-alignment checks
2. Rough alignment to “eyeball clean” (with bolts loose).
3. Rough soft foot: Loosen all bolts and “fill any obvious gaps”.
4. Initial alignment. Get to within 5 to 15 mils at coupling or less than 20 mils at feet.
5. Final soft foot. All feet less than 2.0
6. Final alignment within tolerances.
Note: Step # 1 includes shim inspection and cleaning of machine supports

What is Soft Foot?

Soft Foot is Machine Frame Distortion.

How does it happen?

Soft Foot can happen from a number of things, including:
• Bent Feet
• Bad Bases (warped, uneven, flimsy)
• Dirt, rust, corrosion under feet
• Excessive number of shims
• And many more…

What should be done about it?

A full and extensive diagnosis should be done on every machine foot to determine whether or not the tightening of that particular bolt is causing machine frame distortion, thereby adding coupling misalignment or machine frame strain.  A few helpful tips to remember are:
• Minimize the total number of shims under each machine foot to no more than 4 shims per foot.
• Make sure the area is clean, including machine feet, bases, shim packs, etc.
• Any jacking bolts that may be causing force against the machine frame should be backed off, so as to not interfere with the soft foot check.
• When checking for soft foot, only one machine foot should be loosened at a time, and the deflection or movement at the shaft noted.

With advancements in technology, PRUEFTECHNIK laser alignment tools can help diagnose whether a machine has a soft foot. The newest addition to the PRUEFTECHNIK line of tools, the Rotalign® ULTRA, not only diagnoses the soft foot condition of the entire machine but tells the user exactly how much to shim each foot, in order to correct the soft foot condition.

So the next time someone tries to pass off a bad Soft Foot problem as not being “that bad”, be aware that it is 50% of the alignment.  Your machine’s Soft Foot condition should be taken care of because if it has not, neither has your Shaft Alignment.

An accelerometer is often used with a magnet to couple the sensor to the machine. The coupling between the magnet and machine is critical to ensure quality vibration data is acquired.

Placing the magnet onto the machine can create an impact that can shock the sensor for several seconds. Collecting data during this time can skew the results. The magnet should be rolled onto the machine to minimize the impact. Once the magnet is “Rolled” onto the machine the analyst should feel the magnet to see if it has a good contact or is loose. If the magnet feels loose try rotating the magnet either clockwise or counterclockwise to obtain a more secure fit. Additionally, move the top of the sensor to check for a secure fit as well.

These steps will help you check for sensor placement issues that could impact the quality of data collected. By making these checks you have also allowed any impact signals from attaching the magnet to the machine to decay out of the signal.

When wiring an online remote monitoring system or accelerometers into a termination box/switch box, it is a good practice to run the cables inflexible or rigid conduit. After the fact, it is highly recommended to label both ends of each cable with their respective measurement location. If ferrule tags are not available for labeling, colored electrical tape can be used and marked with an indelible marker.

If you have an online monitoring system, it is recommended to send data (overall vibration), alarm values, and machine status to your process control system or DCS. The data can be sent using MODBUS TCP/IP or MODBUS RTU. This way, there is no need to run extra wires into your control system.

Many accidents can be avoided by simply following a company’s safety procedures. There are many things that might not be considered when thinking about safety. For example, keeping your workplace clean, and free of debris. If objects or spills are left around the work environment, anyone may trip or slip on them. Debris can also end up on or inside machinery and damage equipment. Knowledge of your surroundings can also keep the workplace safe. Know where the nearest fire extinguishers are, and where the emergency kill switch for your machinery is located, as well as emergency exits, and first-aid kits.

Improper attire can also be a safety hazard if not appropriate. Neckties are taboo and long hair should be picked up in a ponytail or tucked in your shirt. Loose long sleeves can get tangled with machinery. Protection of the eyes, ears, and head is imperative while in the factory environment.

In intrinsically safe (IS) environments, any electronic components that enter the area must be certified as IS. An item can be deemed as IS when its potential electrical and/or thermal energy is low enough that, within a hazardous atmosphere, ignition will not take place. Cell phones, digital cameras, and MP3 players are not intrinsically safe and can be hazardous in explosive atmospheres. If working in an intrinsically safe environment, follow your company’s safety guidelines for a better, safer workplace.

Awareness and communication are also important when it comes to safety. Warning your coworkers when they are violating safety procedures can avoid many accidents. It is good practice to advise those around when a machine is being turned on, or when hazardous materials have been exposed. Always obey all safety regulations. They are in place for our own benefit, not just the company’s.

When performing a Dynamic Balance procedure a few things should be considered:

1.  Inspect the structure/mounts and ensure there are no cracks or loose bolts.

2.  If driven via a belt drive make sure that the belt is in good condition and properly tensioned.
• Remember that the second harmonic of a belt frequency can be very close to the rotational speed of the drive.

3.  Inspect the rotating element for the build-up and clean as necessary.
• Remember that even slight build-up (i.e., dust) can be the cause of an unbalance.

4.  If the rotating element is a blower, count the number of blades.
• Frequently correction weights will have to be attached to the blades and therefore it may be best to use a fixed location method.

5.  If the equipment is down when you arrive, replace the reflective tape or attach new tape as may be required.
• This will ensure accurate phase data.

6.  When taking your initial phase data turn the averaging function off, if possible.
• Monitor the phase data for a brief time to ensure its stability. Doing this could identify potential problems.

7.  Keep good documentation, keep written notes on what was found:
a.  Phase and amplitude data
b.  Number of blades
c.  Correction locations
d.  When weights were attached or removed
e.  How much weight was attached or removed
f.  Sensor placement
g.  Tachometer placement.

8.  If the equipment is variable speed such as VFD drive or DC drive ensure that the speed is repeatable to within 5% or less run to run.

PERMALIGN® is the world’s leading machinery positional change measurement system. Since 1986, it has proven itself as the most accurate and dependable solution for thermal growth measurement. PERMALIGN is a laser-based system capable of detecting and accurately measuring both relative or absolute movement, depending on the prisms and setups selected. To this day, it remains unequaled in ease of use and precision of measurement.

A great majority of the PERMALIGN applications involve installing two roof prisms and two laser monitors on the inboard bearing housing of each machine.  By measuring the bearing housing movement, the alignment change can be determined from the relative movement of the machines.  The preferred method of installation is to drill and tap a 10-32 × ½” deep hole into some part of the machine that is directly connected to the bearing housing as shown below.

Sometimes, this is not possible. The next solution is to construct a strong bracket (usually of 5/8″ thick steel plate) that can be physically attached to the bearing housing.  This usually involves temporarily replacing a housing bolt with a longer bolt that allows the bracket to be “sandwiched” to the machine as shown below.

Sometimes, the presence of obstructions (proximity probes, electrical conduit, piping) can interfere with the positioning of the brackets and the PERMALIGN components.  When designing brackets for these situations, the fastest and easiest method is to take advantage of CAD.  I am not referring to “Computer-Aided Design”, but something far more effective in the field – “Cardboard Aided Design”!
Get a piece of cardboard, and a pair of scissors, and cut out a template for the bracket that you will need.  You can bend it in any shape you wish and mark your mounting points with a marker.  Need to make a design change?  Just cut it to change the dimension!  As shown below, this precision-engineered template was crafted with a pocket knife.
Below is the template next to the fabricated piece.  The template provides an easy-to-follow map for building the bracket.  PERMALIGN brackets are usually torch cut in the field, ground, and welded together.  The design emphasis is for it to be STRONG, not pretty!

Below is the final result.  The cardboard template allows the design to be checked prior to fabrication and installation.

Many of you watch or at least are familiar with the various Crime Scene Investigation (CSI ) television series where advanced forensic techniques are utilized to catch the criminals or “bad actors”.  When it comes to your “bad actors” from an equipment perspective, where is your CSI unit? What is your forensic approach to equipment failure?

Rather than simply accepting equipment failures, they should be literally treated like crimes against your organization.  These failures rob the organization of equipment availability and capacity, divert your Maintenance resources, consume spare parts, and steal profit. While you may not be able to prevent failures from occurring, at a minimum you need to understand why they occurred from a root cause perspective.

To do this, perform an autopsy on the failed equipment. Cut apart failed bearings or open gearboxes as examples. Inspect the components. Ideally, the Maintenance Engineering group should become your CSI Unit and investigate to understand the root cause.  In the event that the organization does not have the Maintenance Engineering function, you can develop a “champion” who is detail-oriented with strong mechanical skills. I don’t advocate rotating the champion function among many people as it takes time to develop the necessary skills.

Another resource for consideration is that many quality vendors provide a service of analyzing the failures so that you can both understand how the component failed, and often at no cost. In addition to vendors, there are a number of other resources available to you such as the Maintenance Engineering Handbook, and searching Google images on the Internet.

In the end, the goal is to understand the possible root cause(s) so that you can modify your practices to ensure the elimination of those potential failures from robbing your organization. If doing autopsies, what are some of the root causes and outcomes that your organization has identified? What other steps or ideas would you recommend regarding autopsies?

This was a guest post from Jeff Shiver, CMRP, CPMM of People and Processes, Inc.