KISS your equipment and improve reliability

September 2, 2014

One of the first rules of good engineering practice is the KISS principle. KISS is an acronym for “Keep it simple stupid”. Basically, this means that most things function best if they are kept simple. It is often believed that expensive complex activities/functions are required to improve equipment reliability. Improving equipment reliability can be complicated and expensive in certain situations. Thankfully, this can be the exception and not the rule within your facility. Don’t focus excessively on the complex and expensive reliability functions you cannot complete and thereby overlook the fundamental things that are required to keep your equipment reliable.

What reliability improvements can you make in your facility that do not require expensive or complicated actions? Start with the “basics” such as:

  • Align (shaft, coupling, etc.)
  • Balance (rotating components: fan blades, impellers, rotors.)
  • Tight (eliminate looseness and excessive vibration.)
  • Lubricate (correctly—not too much or too little!)
  • Inspect
  • Apply condition monitoring
  • Understand where your efforts should be focused

Don’t wait until the equipment has been installed and is operating. The basic functions listed above must be included in the specification, design, purchase and routine operation of your equipment. Failure to address these vital aspects from the beginning through operation of your equipment will result in higher maintenance costs and reduced equipment reliability.

Often fundamental reliability functions are not completed due to a lack resources, understanding, time, funding, etc. Ensure that your engineering, maintenance, production, purchasing and management teams understand and routinely employ these fundamental maintenance practices to keep your equipment reliable from the beginning.

Watch video tutorial about Reliability Basics

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Many Man-hours Saved on Critical Gas Turbine Alignment Job

August 28, 2014

A customer in Florida needed to do an alignment between a gas turbine and a generator. Their main issue was that the gas turbine shaft could not be rotated by hand and engineering was reluctant at that time to turn on the lift oil pumps. This customer owns and uses the ROTALIGN ULTRA iS. We suggested using the Multipoint measurement mode in the ROTALIGN ULTRA iS in conjunction with one ALI 2.230 Magnetic Sliding Bracket for the turbine shaft and one ALI 2.112set Compact Magnetic Bracket. With the shafts uncoupled, the generator shaft could be rotated to any position, and the sensor could be positioned at any rotational position on the turbine shaft with the magnetic sliding bracket. A very big advantage of using the ROTALIGN ULTRA iS in the Multipoint mode is that thanks to the quality factor value obtained from the readings a very clear picture emerges of the quality of the data obtained while taking the readings. Any rogue measurements caused by surface imperfections in the turbine coupling can be eliminated without compromising otherwise good data. The ROTALIGN ULTRA’s Technical Note # 12 – for Non- Rotating Shafts was provided to the customer to better guide the process.

Magnetic bracketSliding bracket

Accurate readings were obtained quickly and efficiently, resulting in many man-hours saved on this critical alignment job.

 

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Triboelectric effect on vibration accelerometers

August 26, 2014

There are two primary types of accelerometers: one is the ICP (integrated circuit piezoelectric) having voltage output, and the other is known as a CLD (current line drive) type, with a current output. The standard ICP accelerometer has a nominal output of 100 mv/g and the output of a standard CLD accelerometer is 9.81µA/g.

Cable movement during low frequency measurements with ICP accelerometers can induce triboelectric noise. Triboelectric noise results when two materials are rubbed together creating an electrical charge between them. Triboelectric noise can be generated by flexing or vibrating the accelerometer cable during data acquisition. Such movement can result in friction between the cable’s various conductors, insulation, and fillers. This friction can generate a surface charge resulting in triboelectric noise. Vibration data collectors will measure the voltage generated by this effect. This can cause data integrity issues with acquired data. CLD sensors output current rather than voltage and are therefore not subject to the triboelectric effect from cable movement.

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Tug Boat Z-Drive Alignment with ROTALIGN ULTRA

August 21, 2014

Recently, while visiting the West Coast, I had an opportunity to get involved in an alignment with Mr. Roy Loop from The Rueck Company on a tug boat being built on the Columbia River near Portland, OR. This tug will be put into service halfway around the world where it will be towing and docking ships into and out of ports. A failure in this remote location would make repairs extremely expensive for the owner, not only due to its service location, but because of lost revenue from the vessel being out of service.

Tug Boat

Knowing this, the tug boat’s owner wanted to verify the alignment of the drive lines (both port & starboard) to ensure they were within the required alignment tolerances before putting the vessel into service.

Dimensions Setup

Interesting about this application is that the drive shaft goes through a bulkhead so there is no line-of-sight between the Z-drive and the diesel engine. In the image below you can see the bulkhead. The diesel engine is on the other side of this bulkhead. In this picture, we are setting up the receiver on a 17-foot jack shaft.

Jackshaft alignment

Rotalign Ultra

Fortunately, we had a ROTALIGN ULTRA iS Laser System (with Expert level firmware). This firmware gave us the capability to set up multiple laser heads on all of the drive train components and thereby measure the entire machine train with just one rotation. Despite the fact that two sets of lasers and receivers were on the other side of the bulkhead, we could still establish communication via the powerful Bluetooth module built in to the laser equipment. The ROTALIGN ULTRA iS is the only system on the market that is capable of performing this alignment measurement across multiple couplings simultaneously with just one rotation of the drive line. In order to rotate the shafts, the drive train typically needs to be cranked by hand using a ratchet on the diesel’s flywheel. This is extremely tiring, time consuming and difficult to do. If you had to “crank” the diesel for each of the four couplings one at a time, the job might take several hours just to take the readings. With this alignment set-up, we were able to use the ROTALIGN’s unique Continuous Sweep measurement mode, so there was no need to stop and start at any specific measurement location.

Three sets of readings were taken to verify repeatability using the ROTALIGN’s unique measurement table. This measurement table allowed us to view each of the coupling’s three readings in a table to verify repeatability and (if desired) average these readings together. Each set of readings was accomplished with just a single turn of the shafts with less than 100 degrees rotation. The entire alignment data collection process (all three sets of readings) was accomplished in just a few minutes.

Laser Receiver alignment setup

When making live moves/corrections, the ROTALIGN ULTRA iS Expert allowed us to see the alignment condition at each coupling simultaneously in real time for both the Vertical and Horizontal directions. This is another unique capability which is extremely important, since, when one component of the drive train is moved, it affects the alignment condition at the other couplings. Having this capability is a huge time saver, reducing the job sometimes from days to just hours.

AS FOUND results:

AsFoundResults

As LEFT results:

AsLeftResults

The alignment tolerances from the coupling manufacturer were given in degrees of angularity rather than as gap differences at the coupling. To verify that the alignment was within the coupling manufacturer’s tolerances, the Rotalign Ultra allowed us to instantly convert the measured alignment condition to display the angle in degrees rather than as a gap. Below is the final reading in degrees:

ResultsinDegrees

The alignment was accomplished within alignment specifications, as shown by the smiley faces. The ship’s owner was confident that alignment would not be an issue and gave the green light to put the tug into service.

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Is the window of enthusiasm closing on your Condition Monitoring Program?

August 19, 2014

Education and responsibility go hand in hand. Leaders of reliability programs should expect their employees to return from a training course with a better idea of how Condition Monitoring can effectively increase equipment reliability and be willing to provide the support to take full advantage of the education gained.

Indeed, there is a narrow window of opportunity to maximize this enthusiasm. Even the most passionate reliability professional eventually will fall captive to the stagnant grind of doing the same tasks over and over, especially when he or she has realized that the status quo is not changing.

Leaders must continuously provide their team with the necessary tools and support to improve their program, while those who are performing the tasks must use what they have learned to effectively increase equipment reliability.

Is the window of enthusiasm closing on your Condition Monitoring program? Have you maximized your staff’s education and opportunities? Reliability Excellence can be achieved when your team collectively contributes and applies the knowledge that has been obtained.

Learn about The Reliability Leader Certification

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Aligning a Gearbox Shaft to Compressor Bores During Assembly with ROTALIGN ULTRA

August 14, 2014

Some weeks ago, a compressor manufacturer contracted us to perform ROTALIGN ULTRA laser alignment training at their testing facility. During the training, the millwrights mentioned that they had a need to align the gearbox shaft to the compressor bores during the assembly process, before the compressor shaft was installed. Since my ROTALIGN ULTRA also features the CENTRALIGN ULTRA bore alignment option, I offered to train them on this interesting application.
The objective was to perform the alignment so when the compressor shaft is put in, it is already within tolerance and the compressor is immediately ready to be tested. This means that the millwrights need to align the static centerline of the bores of the compressor to the rotating centerline of the gearbox shaft. This is a challenging application that the ROTALIGN ULTRA with CENTRALIGN ULTRA can handle with ease (see Figure 1.)

 Laser on Gearbox

Fig. 1: Laser mounted on Rotating Gearbox Shaft

We first covered the key concepts of what it means to do a bore alignment. Hands-on exercises illustrated the differences between aligning with a static laser beam through the bores and a rotating laser setup on the gearbox shaft. Once on the shop floor we were able to measure a compressor’s bores with respect to the gearbox shaft within 45 minutes, start to finish including setup time for both stages of the measurement (see Figure 2.)

Receiver on Compressor Bore

Fig. 2: Receiver with Bluetooth module in compressor bore

The millwrights seemed thrilled with the simplicity of the process, compared to their current approach, which involved using a complicated bracket system to support dial indicators, sometimes taking up to a day to obtain accurate measurements.

The customer purchased the ROTALIGN ULTRA with CENTRALIGN ULTRA option and now obtains accurate and repeatable measurements within an hour, without depending on the skill level of the operator. This has freed up manpower, saved time and a great deal of money during the compressor assembly process.

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