Vibralign Blog

the validity rule| "repeatability"| Precision Shaft Alignment

By Michael Keohane on February 5, 2020

The validity rule is an important concept in precision shaft alignment. It can be used to confirm that your readings are accurate and is why we don’t have to rotate a full 360 degrees in order to get accurate alignment information. Here is a previous blog post with an embedded video that discusses dial indicator […]

rotor unbalance| unbalance| Imbalance

By Michael Keohane on February 7, 2019

Unbalance (Imbalance) is often defined as the unequal distribution of the weight of a rotor about its rotating centerline. A rotor can be balanced either in-place or in a balancing machine assuming unbalance is the issue and weight can be added or removed.  Modern balancing instruments will do the math for you. I originally learned […]

OL2R| "thermal growth"| "thermal offsets"| "thermal growth targets"

By Michael Keohane on January 23, 2019

The goal of a precision alignment is to align the machine within tolerance when at operating condition. Many, but not all, machines are aligned without the need to compensate for offline to running (OL2R) movement most often associated with thermal growth. A previous blog post (see link below) discussed how to read an alignment report […]

Fixturlaser NXA Pro| Fixturlaser NXA Ultimate| vertical alignment| Omniview| "vertical shaft alignment"

By Michael Keohane on September 14, 2018

Many modern laser alignment systems include inclinometers that aid in the alignment process. Inclinometers, however, don’t work on vertically oriented machines. These include vertical “C” faced machines as well as vertical machines with feet. This meant that vertical machines required a 180-degree swing for accurate measurements and sensors were positioned the old-fashioned way by aligning […]

"cooling tower alignment"| Alignment tolerances| spacer shaft| spacer shaft alignment| Precision Shaft Alignment| Cooling Towers| offset and angularity

By Michael Keohane on April 25, 2018

The majority of precision shaft alignments are relatively close coupled where there are only a couple of inches between the shaft ends of the driver and driven elements. Close coupled alignment quality is traditionally displayed as angle (driver to driven) and offset (at the center of the coupling). The question is what do you do […]

machinery diagnostics| Vibration Analysis| maintenance reliability| Precision Shaft Alignment| Balancing

By Michael Keohane on August 16, 2017

I read an interesting article in the June/July 17 issue of Uptime Magazine. It was titled “The Reliability Impact Within the P-F Curve” by Randy Riddell. Randy is the Reliability Manager for the SCA Barton Mill in Alabama. I encourage you to read the full article (https://reliabilityweb.com/articles/entry/the-reliability-impact-within-the-p-f-curve). The article includes the following graphic that I […]

machinery diagnostics| condition monitoring| machinery vibration| Hawk| ONEPROD Hawk

By Michael Keohane on May 10, 2017

Knowing the correct shaft speed of both shafts on a belt-driven machine is important when performing machinery diagnostics. Ideally you would do this by first identifying the input and output speeds using a strobe light, photo tach or laser tach. Once you know the accurate speed of both components, use this formula to determine the […]

Fixturlaser NXA Pro| "thermal growth targets"| "thermal offset"| "thermal growth"| Dial Indicators| Laser-Dials

By Michael Keohane on November 23, 2016

A client was aligning a motor-compressor set and wanted to use the OEM specifications for thermal growth (OL2R) compensation. The manual gave the target values as rim and face dial indicator numbers for either the motor hub or compressor hub. In this case the motor hub specifications were used. He was using the Fixturlaser NXA […]

"shaft alignment training"| "laser alignment"| Dial Indicators

By Michael Keohane on August 20, 2015

Proper training is a critical component to success when using precision shaft alignment tools. This is true regardless of the measurement methodology. I often hear people say that it is important to learn dial indicator shaft alignment first to gain a better understanding of the alignment process. Really? After all, you don’t need to learn […]

"alignment targets"| "thermal offset"| "thermal targets"| "thermal growth"

By Michael Keohane on May 13, 2015

Dynamic Movement, often thought of as thermal growth, is a hot topic among alignment professionals (I’ll be here all week!). Plant Services Magazine in conjunction with VibrAlign recently hosted a webinar on this subject (details below). One of the more popular ways to compensate for thermal growth is through the use of a thermal growth […]

"thermal offset"| "thermal growth"| OL2R| "Cardan Shafts"| Precision Shaft Alignment| "alignment targets"

By Michael Keohane on October 29, 2014

OL2R Measurements (Offline To Running) are used to collect very accurate (and actual) Thermal Growth Values and Targets for critical rotating machinery. Offset Measurements (Cardan Shaft) are critical for offset drives to ensure there is no angular misalignment causing lead/lag issues with the drive shafts resulting in production related quality problems. Both the OL2R and […]

pipe Strain| "shaft alignment"| Alignment tolerances

By Michael Keohane on July 7, 2014

Pipe strain is a relatively common problem seen in pump installations. It is a cause of premature bearing and seal failure. Here is a link to an excellent article from Pumps and Systems magazine that discusses the detrimental effects of pump strain. http://www.pump-zone.com/topics/seals/how-do-plant-pipe-strain-problems-affect-my-pumping-systems You can easily measure the effects of pipe strain using dial indicators […]

aligning machinery| rim and face| Alignment tolerances| Dial Indicators| "shaft alignment"

By Michael Keohane on January 29, 2014

VibrAlign released the free Laser-Dials App to aid laser system users who need/want to convert their laser shaft alignment system results to rim and face dial indicator readings. You can also use the App to convert dial indicator readings to laser readings. Most are interested in converting laser results to dials so that is what […]

Alignment tolerances| "precision alignment"

By Michael Keohane on January 9, 2014

Occasionally we get asked how to convert shaft alignment angularity values expressed as mils (thousandths) per inch to degrees. Since mils per inch is the rise over run that means that the conversion to an angle is the arctangent. Or the conversion from an angle is the tangent of that angle. Remember to include the […]

aligning machinery| "precision alignment"| Alignment tolerances| Fixturlaser NXA Pro| "shaft alignment"

By Michael Keohane on May 1, 2013

Most maintenance personnel understand that documenting a precision shaft alignment is a good idea, but don’t always understand how to interpret the data. Here is a quick primer on how to read a typical alignment report. This shaft alignment report happens to be from a Fixturlaser NXA Professional but all alignment reports should contain similar […]