The safety strap which is included with the analyzer should be checked for condition prior to each use. Most safety straps use Velcro and the Velcro is there for your safety. The strap is designed to separate to prevent injury should your cables become tangled in the rotating shaft or some other moving part of the machine.

Replace the straps if the Velcro becomes dirty or no longer holds. Never glue, bolt, staple, or otherwise permanently affix a strap to the analyzer, because this could prevent the strap from functioning correctly and result in serious injury to you or a coworker. 

Background

The practice of dowel pinning machinery was originally conceived within the U.S. Navy, well over a century ago. This innovation was triggered by the need for a solution to the extreme conditions faced onboard naval surface vessels and submarines by directly-coupled rotating machinery with respect to hull and foundation deflection related to changing temperatures and storms at sea, as well as the forces generated by firing munitions (shells and depth charges.) The original concern that resulted in the use of dowel pins was positional security.

Given the fact that on Navy and commercial vessels excess mass is a major concern, the sound engineering practice of designing a base structure to weigh three to five times the mass of the machinery mounted upon it is impractical, resulting in flimsier, more flexible foundations. This is the principal justification for dowel pinning machines in the Navy, and this practice became almost universally adopted.

After World War II, the vast majority of the industrial maintenance workforce in the United States that dealt with rotating machinery was comprised of men who had served in the Navy, as this was the branch of the armed services with the bulk of such machinery and maintenance need. As a result of deeply ingrained Navy tradition and training, the practice of indiscriminately dowel-pinning all rotating machinery filtered out onto dry land installations, even though in most cases there was no longer any technical justification for this practice.

Download our article “Thoughts On Dowel Pins In Machine Feet” including Positional Security: Technical Considerations, Alternative Solutions and Positional Repeatability.

This webinar by Greg Lee deals with Field Balancing specifically with the following learning points:

• Types of Unbalance
• When do I Two-Plane Balance?
• Balancing Caveats – Field “Gotchas”

VIBXPERT II Balancer

Field Balancing can be a lot like walking through a mine field. For example:

• The customer insists that a fan is out of balance when it is in fact misaligned.
• The customer wants to run a machine at a critical speed.
• Your scale gets dropped.
• The balancing measurements will not repeat.
• The trim weight makes the vibration worse.

There are a host of field related problems that can make field balancing difficult.

Come join us at our webinar where we will discuss balancing “gotchas” and how to overcome the difficulties of field balancing.

Date: Thursday, May 31, 2012
 
Time: 1:00 – 2:00 PM EDT

Reserve your Webinar seat now!
(Space is limited)

After registering you will receive a confirmation email containing information about joining the Webinar.

Even if you will not be able to attend the live webinar due to time or schedule conflicts, please register. We will email you a link to the recorded webinar as soon as it becomes available.

Hosted by LUDECA in collaboration with Reliabilityweb.com

Soft Foot has often been noted as the most inexact science portion of Shaft Alignment. Historically, when people think of Soft Foot, they often want to neglect, ignore, or otherwise do everything possible to not deal with it. This is one of the traps that leads down the path of bad habits, bad alignments, and more problems down the line. 

Shaft alignment can be thought of as two things: 1) Aligning the couplings and 2) Checking for and correcting Soft Foot. Soft Foot, in fact, plays so much of a role in shaft alignment, that if one were to analyze the 6-Step Alignment Procedure below, one can see that Soft Foot actually appears in 3 out of the 6 steps. Therefore, Soft Foot can be thought of as half the alignment job.

Overall Alignment Procedure
1. Pre-alignment checks
2. Rough alignment to “eyeball clean” (with bolts loose).
3. Rough soft foot: Loosen all bolts and “fill any obvious gaps”.
4. Initial alignment. Get to within 5 to 15 mils at coupling or less than 20 mils at feet.
5. Final soft foot. All feet less than 2.0
6. Final alignment within tolerances.

Note: Step # 1 includes shim inspection and cleaning of machine supports

What is Soft Foot?
Soft Foot is Machine Frame Distortion. 

How does it happen?
Soft Foot can happen from a number of things, including:
• Bent Feet
• Bad Bases (warped, uneven, flimsy)
• Dirt, rust, corrosion under feet
• Excessive number of shims
• And many more…

What should be done about it?
A full and extensive diagnosis should be done on every machine foot to determine whether or not the tightening of that particular bolt is causing machine frame distortion, and thereby adding coupling misalignment or machine frame strain.  A few helpful tips to remember are:

• Minimize total number of shims under each machine foot to no more than 4 shims per foot.
• Make sure the area is clean, including machine feet, bases, shim packs, etc.
• Any jacking bolts that may be causing force against the machine frame should be backed off, so as to not interfere with the soft foot check.
• When checking for soft foot, only one machine foot should be loosened at a time, and the deflection or movement at the shaft noted.

With advancements in technology, PRUEFTECHNIK laser alignment tools can help diagnose whether a machine has a soft foot. The newest addition to the PRUEFTECHNIK line of tools, the Rotalign ULTRA, not only diagnoses the soft foot condition of the entire machine, but tells the user exactly how much to shim each foot, in order to correct the soft foot condition.

So the next time someone tries to pass off a bad Soft Foot problem as not being “that bad”, be aware that it is 50% of the alignment.  Your machine’s Soft Foot condition should be taken care of, because if it has not, neither has your Shaft Alignment.

An accelerometer is often used with a magnet to couple the sensor to the machine. The coupling between the magnet and machine is critical to ensure quality vibration data is acquired.

Placing the magnet onto the machine can create an impact which can shock the sensor for several seconds. Collecting data during this time can skew the results. The magnet should be rolled onto the machine to minimize the impact. Once the magnet is “Rolled” onto the machine the analyst should feel the magnet to see if it has a good contact or is loose. If the magnet feels loose try rotating the magnet either clockwise or counter clockwise to obtain a more secure fit. Additionally, move the top of the sensor to check for a secure fit as well. 

These steps will help you check for sensor placement issues that could impact the quality of data collected. By making these checks you have also allowed any impact signals from attaching the magnet to the machine to decay out of the signal.

We will have all our shaft alignment, pulley alignment and vibration analysis and balancing maintenance-related products on display at the following trade shows:

WINDPOWER 2012
Network with wind professionals, learn from industry leaders and experts and discover the latest in wind industry products and services. 
Booth# 6160
June 3 – 6, 2012
Atlanta, GA
Register now!

CBM 2012
Designed for anyone who is responsible for establishing, creating, or managing a condition-based maintenance or predictive maintenance program.
June 5 – 8, 2012
Fort Myers, FL
Register now!

ACE 2012
The place where water professionals can be leaders and learn from leaders in the water industry.
Booth# 1125
June 10 – 13, 2012
Dallas, TX
Download FREE Expo Hall Pass

Design & Manufacturing Midwest
Talk face-to-face to suppliers, get updates on the latest technologies and learn about new products, materials and services.
Booth# 1741
June 19 – 21, 2012
Chicago, IL
Register for FREE Expo Hall Admission and save the $55 entrance fee. Use Promo Code XG.

EASA (Electrical Apparatus Service Association)
This event provides excellent education sessions and networking opportunities that will help you continue with the highest standards in “Moving Industry Forward.”
Booth# 1322
June 24 - 26, 2012
Nashville, TN
Download FREE Expo Hall Pass