Alignment With A Lot of Vibration

June 23, 2015

One of the big problems I’ve seen people run into when doing alignments is a lack of repeatability due to high vibration from nearby machinery. It’s obviously pretty difficult to align something that’s moving several thousandths. There are still ways to get accurate readings with some laser alignment tools.

Let’s say you are in the same situation but aligning with dial indicators. The indicator needle is jumping back and forth between 35 and 42. Most likely, you will settle for the average midpoint of 38 or 39. You can do the same with lasers.
The first thing to do would be to switch over to one of the “manual” measure modes (like Multipoint mode) rather the fully automatic measurement modes (like Continuous Sweep or Pass Mode.) In Multipoint, you can adjust the averaging (sampling time) for each reading and spend a little more time taking each point. A longer sampling time will allow the tool to take much more data at each measurement position and average the data together very accurately, unlike guessing as with the dials. It is also a good idea to take several positions (8 or more) around 360 degrees of rotation. While the minimum required is 5 points over 70 degrees of rotation, the more points and the more rotation you have, the better your results will be. Check your repeatability. If it’s not good, look at your Standard Deviation values. These should be very low. If they’re not, then perhaps your averaging still isn’t set high enough to overcome the surrounding vibration problems. If you can’t get repeatable numbers, spend a little more time taking readings. No one likes chasing their tail making fruitless or inaccurate corrections.

Live move can also run into some problems in high vibration scenarios. Make sure you adjust the averaging value for the Move Function to the same value with which you took successful readings. It may take longer for the results screen to update but will steady the move and greatly improve its accuracy.

The thing to keep in mind is that a good laser alignment system measures down to 1/25,000 of an inch. If the laser is moving, it will affect your readings. Just know how to overcome the problems when you run into them.

We recommend that you take a look at our Alignment Matters Repeatability Video Tutorial

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Caribbean Goes Wireless with VIBCONNECT RF Condition Monitoring System

June 16, 2015

Are you running out time to get your job done? Has your boss or supervisor saddled you with extra responsibilities? Are you not performing your PM tasks on time due to these extra responsibilities? If you answered yes to any of these, don’t feel alone in this ever changing industry. We are all being asked to perform more with less tools and time. And yes, we must keep our equipment up and running!

I recently ran into this problem at a water treatment facility in the Caribbean. Besides the overwhelming amount of work demanded of the maintenance staff, they also have been unable to maintain their equipment. The plant was going longer than four months without any vibration analysis data collection on their machinery, resulting in preventable equipment failures with the consequent lost revenue and high cost of replacement. Due to the working environment, culture and qualified staff shortage, the engineering group decided to invest in a wireless vibration monitoring system for their highly critical machinery.

After careful evaluation, they decided to install 8 VIBCONNECT RF sensors on four of their high pressure pump sets. These pumps are critical in processing sea water into fresh water. Although the process of a desalination plant has several stages, the plant decided to first outfit these (four) 550 HP motors first before proceeding with the rest of the facility.

These critical pump motor sets cannot be ignored and have a good reliability program in place. Nor can they be ignored without end user (consumer) dissatisfaction from no clean water availabality due to equipment reliability issues. The plant made a small investment in the monitoring system in comparison to the cost of replacing the motors which failed.

As the maintenance manager stated:

If we could have prevented that failure and/or known that the asset was headed in that direction, we could have saved thousands of dollars. Not to mention the embarrassment of the bad press that comes from working in a government run institution…“

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How to Avoid Machinery Damaged or Unserviceable After Storage

June 9, 2015

Putting your machines away for future use may appear a simple operation; however, there are pitfalls that you should try to avoid. Storing machinery for certain lengths of time can bring about damage that could render that machine or some of its components inoperable to you when the time comes to use it. Here are some storage tips for success:

  • First, select the driest environment available for storage. Surface corrosion is the enemy of every machine and thrives in moist air.
  • Also, coat any and all exposed metal surfaces with a lubricant or oil mist to help prevent oxidation.Now that the machine and components are in storage, do not forget to maintain them. If your machine has moving parts, regular movement and rotation of its movable components will ensure that they run smoothly when brought into service.
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How do you set your condition monitoring intervals?

June 2, 2015

A lot of facilities assign condition monitoring intervals based upon arbitrary schedules such as 30, 90, 180 or 365 days. Often, this is due to a lack of understanding of how equipment fails, misunderstanding how conditional tasks such as vibration analysis work, available labor and lack of importance placed upon condition monitoring efforts. These arbitrary collection intervals can actually lead to failures that go undetected and a loss of value from the effort.

To appropriately determine monitoring intervals, a couple of things should be known. First, the point in time (P) that the potential failure becomes detectable must be known (detected with vibration monitoring, for instance.) Second, the time (F) at which the potential failure would degrade to a functional failure must be known. This difference in time (P-F Interval) is the window to take corrective action and avoid the negative consequences of the failure. This difference in time will determine how often conditional tasks such as vibration monitoring must be done to detect potential failures from such things as bearing issues, etc. Typically, the monitoring interval would be set to half of the P-F interval. This allows enough time for the technology to detect the problem and corrective action to be taken. However, in certain circumstances it may be necessary to collect data at shorter intervals than half of the P-F interval.image1 -june blog

It is important not to assign monitoring intervals based upon gut feelings, arbitrary calendar intervals, and so forth. Let the equipment tell you how often monitoring must be completed. Not understanding the process above can lead to costly results!

 

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Overcoming Lack of Space with the Right Brackets for Shaft Alignment

May 26, 2015

Surprisingly, often on larger machines like gas turbines and diesel engines coupled to generators or compressors there is less space to mount your brackets than on small machines. The large size of couplings and shafts frequently means that there is very radial clearance the OD of the coupling hub to provide line of sight, or piping or other structures interferes with rotation, limiting your axial clearances on the shafts as well.

Also, shrouds or other obstacles limiting access to the shafts can cause difficulties in turning them. Yet, there is almost always a way to do an alignment with Pruftechnik tools. Our brackets do not need to be mounted on the shaft, provided the coupling hub is solid to the shaft (ie. rigidly mounted to the shaft.) A variety of magnetic brackets and offset adapter lets you overcome almost any obstacle to rotation or to line of sight. In fact, anywhere that you can devise a way to mount a dial indicator, you can also mount a bracket to hold a laser component. Here are a few examples:

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Here we see the ROTALIGN SMART EX laser component and Bluetooth module mounted on solid hub, shooting the beam through the coupling bolt hole. The laser emitter is mounted on the magnetic coupling bolt hole bracket designed for applications like this, and the Bluetooth module is mounted on a compact magnetic bracket, illustrating that the two components need not always necessarily be mounted on the same bracket. This setup allows the laser beam to be shot through an unoccupied bolt hole of the coupling without any hardware protrusion beyond the OD of the coupling.

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Here we see the ROTALIGN ULTRA IS sensALIGN laser (on the right) mounted with a compact magnetic bracket to the axially protruding face of the solid hub of the double-engagement gear coupling, in a a very limited axial space that would not permit a standard chain bracket to be mounted on the shaft. An offset adapter moves the laser unit forward axially, permitting the setup to overcome the axial obstruction of the machine housing at 3 o’clock.

image3Here we see the ROTALIGN ULTRA laser (on the right) mounted on magnetic bolt hole bracket to the flywheel of a methane gas engine, overcoming the axial space limitations posed by the shim disk-pack type coupling.

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Here we see the ROTALIGN ULTRA receiver mounted on offset support posts on a compact magnetic bracket, overcoming both an axial space limitation preventing use of the chain brackets and a radial obstruction posed by the pipe seen in the foreground on the left.

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Here we see the ROTALIGN SMART EX receiver mounted on a compact magnetic sliding bracket, overcoming both an axial space limitation and a situation in which the shaft cannot be turned by hand. Instead, the magnetic sliding bracket is slid around the solid coupling hub to each measurement position while the laser is rotated past the receiver as the other shaft is rotated using the Pass Mode measurement mode for uncoupled shafts.

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Successful Project with WEARSCANNER particle counter at Pumping Station

May 19, 2015

A facility just replaced several 1,000 HP slurry pumps with a massive 4,000 HP slurry pump at a pumping station. As part of this project, Ludeca supplied a WEARSCANNER particle counter that is installed on the oil return line just before the filter. This system reports partials per minute for different particle ranges and relays this data via Modbus to the process control computer. During the initial start-up the particle counter showed particles passing through the counter with the worst range reporting 6 parts per minute in the 100 to 125 micron range. The startup oil was changed and the filter replaced.  As a result, the particle count has now dropped to zero in all of the ranges.

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