Blog

December 7, 2016

Why and How to Measure in Clock Method

By Tom Shelton

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Proper use of any tool is essential to success in achieving your desired goal. Many tools have optional configurations to adapt that tool to your needs. Fixturlaser Precision Alignment Systems are no different. The alignment tools produced by Acoem/Fixturlaser are second to none in ease of use. The Acoem AB design engineers do all they can to provide the end user with an alignment tool that can be used in virtually any circumstance.

Following that line of thinking there are different measuring methods available to acquire accurate alignment data when performing a precision shaft alignment. The following example is for the Fixturlaser NXA, other Fixturlaser alignment systems are similar.

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Almost every shaft alignment can be done in Tripoint or Express measuring methods. This means that measurements can be acquired at any position in the rotation of the shafts. It is not necessary to utilize clock positions or any other predetermined positions when measuring using either of these methods.

Tripoint and Express measurements are able to be taken at any point in the shaft rotation thanks to the inclinometers in each sensor. The inclinometer values are part of the calculation to determine vertical and horizontal position of the movable machine.

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Clock method is the most rudimentary method of measurement and is a carryover from the “traditional” reverse dial indicator alignment. Clock method alignment readings are taken at 9 o’clock, 3 o’clock, and 12 o’clock. Based on the Validity Rule only 3 measurements are required.

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Where would this be useful?

Clock method exists to accommodate odd alignment situations. Here are a few;

  • When the surrounding area is vibrating excessively, beyond the control of the vibration filters built into the Fixturlaser Alignment Tool. This is highly unlikely.
  • When a machine base is not truly horizontal and vertical. Example, Mounted on a 45-degree angle, vertically or horizontally.
  • When a horizontal machine is mounted on a vertical plane.

To reiterate, this is a useful function when needed though almost every shaft alignment scenario can be measured using Tripoint or Express Measuring methods. Also worth noting is VibrAlign’s Verti-Zontal Process can still be performed when using the Clock Measuring Method.

If you are having challenges and thinking of using the clock method of measuring, consult your owner’s manual or call a Technical Trainer here at VibrAlign to help you.  800-379-2250

 

2 Comments

  1. VARUN TRIPATHI on January 25, 2017 at 11:44 am

    Dear Sir,
    I want to know it there is any positive or negative sign used in validity rules for pump alignment . If it is please explain it how it is to be calculated …



  2. Tom Shelton on January 27, 2017 at 6:04 pm

    Yes, standard mathematics rules apply. As an example, if you zero your Dial Indicator at the 12 o’clock position rotating clockwise to 3, 6, and 9 o’clock. Let’s say your 3 o’clock reading is -5, your 6 o’clock is +30, this would mean that your 9 o’clock would have to be +35. Top+Bottom = Side+Side. Therefore we only need three readings 90 deg. apart to determine if we have a valid measurement. Please see our video on YouTube, “Dial Indicator concepts and the Validity Rule”.
    Thanks for asking.