Aligned at the Factory – Realigned in the Field

An alignment check was performed on a new pump skid that had been recently installed as part of new construction. Even though it did not have much run time there were already telltale signs of misalignment as indicated by the coupling insert dust on the base. The new pump skid came aligned from the factory. …

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Static, Couple, and Dynamic Unbalance

According to the International Organization for Standardization (ISO), unbalance is “that condition which exists in a rotor when the vibratory force or motion is imparted to bearings as a result of centrifugal forces”. In other words, unbalance is an unequal weight distribution of a rotor around its rotating centerline. The rotating centerline or rotational axis…

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Using a Strobe Light to Verify RPM

Knowing the correct rotational speed is critical when performing machinery diagnostics. A strobe light can be an excellent tool for determining speed. Look for a unique mark such as a keyway, piece of tape, etc. to use as a reference. You will adjust the flash rate of the strobe light until you only see one…

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Uncoupled Alignment

Although most machines are aligned with the coupling installed there are occasions where it is better to align a machine uncoupled.  A couple of considerations: 1 – Shafts are rotated independently. 2 – Use the inclinometers (outside two numbers) to match angles within less than .5 degrees before taking a measurement. 3 – The shafts…

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Why Don’t I Input a Coupling Diameter?

We often get asked why we don’t input a coupling diameter when performing a precision shaft alignment with the ACOEM laser alignment systems. The coupling diameter (or more correctly sweep of a face dial indicator) is only required when doing a rim and face dial indicator alignment or when the user wants to know the…

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Don’t Forget a Lift Check!

    A lift check isn’t always done when performing a precision shaft alignment, nonetheless excessive lift can be the cause of alignment frustration. Here is a recent example from a very experienced aligner. This particular alignment was on a 150 HP motor driving an extruder through a gearbox. The horizontal alignment came in as…

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Qualifying the Fixturlaser Level When Using a Fixture

The Fixturlaser level is calibrated to earth level out of the box. If the level is used without a fixture it reads level directly. If a fixture is used, however, you must first qualify the level with the fixture. This is a very simple procedure when using the Fixturlaser NXA. Level measured with no fixture…

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The Fixturlaser Level – a digital two axis high precision machinists’ level

The Fixturlaser Level is a high precision two axis digital machinist level. The primary application is base leveling. The Fixturlaser Level offers the following advantages: Two axis live measurement Calibrated to earth level out of the box No line of sight required Immediate feedback with live values Documentation of results Simple to qualify to other…

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Using Your Laser Alignment System to Check the Validity Rule

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…

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A Vector Approach to Single Plane Balancing

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…

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How to Read an Alignment Report Part 2 – Thermal Growth Targets

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…

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Vertical Alignments Using the Fixturlaser NXA Pro OmniView

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…

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Understanding Spacer Shaft Alignment

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…

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Precision Alignment and Balance isn’t Important – Unless you care about budgets and the reliability of your rotating assets.

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…

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Calculating Output Speed Using Pulley Diameters and Input Speed

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…

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