March 08, 2007 Hey Predictive Maintenance Professionals!
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Each and every month you will find features on:
-Vibration Analysis
-Infrared Thermography
-Oil Analysis
-Motor Testing
-Ultrasonics
-Precision Maintenance
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March 08, 2007 Maintenance Tip – Lubrication
Rust, a form of corrosion, develops when iron, water and oxygen are present. When water comes in contact with iron, the water combines with carbon dioxide to form an acid. The acid dissolves the iron. During the dissolving process, a portion of the water breaks down into hydrogen and oxygen. The oxygen and dissolved iron bond into iron oxide, better known as rust. This bonding of oxygen and dissolved iron frees electrons from the iron (acting as an anode) which travel to the cathode. This movement of electrons corrodes the iron material.
Assembly fasteners and components on stationary and mobile equipment—which are continually exposed to nature’s elements (water, dirt, and temperature variation)—can be difficult to disassemble due to corrosive affects of these elements. Heavily rusted fasteners can break-off or be damaged beyond use during disassembly. Additional maintenance time and costs are required to extract fractured fasteners and repair damaged components. When planning to disassemble equipment, the equipment should be inspected prior to disassembly to determine the condition of the fasteners and components.
Lessons Learned: If the fasteners and components are heavily rusted, then it is suggested that a quality, penetrating oil be applied to these items. The penetrating oil should be applied 12 to 24 hours prior to disassembly and may require more than one application. This will allow the penetrating oil to work at loosening the joined parts and greatly reduce the chances of damaging or destroying these items while reducing unplanned work.
Tip provided by Andy FitzGerald, Reliability Engineering Services Consultant, Allied Reliability
http://www.alliedreliability.com
March 08, 2007 The Reliability Centered Maintenance Managers' Forum
RCM-2007
April 3-6
Sheraton Waikiki - Honolulu Hawaii
Please join us for RCM-2007 the Reliability Centered Maintenance Managers’ Forum, April 3-6, 2007 in sunny and beautiful Waikiki Beach in Honolulu Hawaii.
We will cut through the marketing hype and promotional fog of each major RCM process to highlight the methodology by presenting actual case studies and reporting on short and long term RCM program results.
There will be real world “how we did it” RCM Case studies and several full and half day RCM workshops. There are plenty of opportunities to network with people who have to solve the same issues you face on a daily basis.
Participants will discover exciting new ideas and learn helpful techniques for implementing or improving reliability centered maintenance.
This year RCM-2007 offers session for RCM Beginners and RCM Advanced Practitioners!
March 08, 2007 Motor Testing Tip
Comparing Torque and Current signatures
Torque calculations use information of all 3 currents and voltages (with their right phasing and correct algebra). Current signature, on the other hand, just uses one current phase, discarding the benefit of the added synchronous information coming from the other 5 data channels.
An outer-race fault bearing fault was investigated using the exact same data but comparing different processing techniques.
One result is that the signal to noise ratio of the torque graph is nearly 5 times higher than the signal to noise ratio of the current graph. This is based on identical data!
The current signature method is about 5 times worse than the torque on this very important measure.
The second measure that was investigated is the “RMS/Signal” measure. Since predictive maintenance is done by people, it is important that a problem show itself strongly enough to be recognized in order to be detected, hence preventing any unplanned downtime.
Comparing the number results, it comes out that the torque signature stands over 125 times closer to the maximal torque signature, than the current signal stands with respect to the current fundamental. The torque signature shows several high frequencies, many of which are related to the mechanical failure. On the current signal, however, there is truly not much that can be seen.
At the end of the day we can say that the torque signal is about 5 times more stable and reliable than the current signal, and more than 100 times easier to find than the current. Consider torque signature analysis for some beneficial predictive maintenance as compared to current signature analysis.
Tip provided by Baker Instruments
+1-970-282-1200
March 08, 2007 EAM/CMMS Tip
Most facilities take little advantage of the scheduling capability of their Enterprise Asset Management (EAM) System. This is in part due to the way scheduling information is displayed. Experience has shown that many rely on exporting the scheduling data to an Excel spreadsheet and use this as their weekly schedule. This format is, of course, limited to the functionality of Excel as a scheduling platform. On the occasion where Microsoft Project is used, data is manually entered to generate the schedule.
If you can easily get your scheduling data from the EAM system into an Excel spreadsheet, a Microsoft Project is really minutes away. A standard week schedule project format can be created as a template. Use this as the basis for future weekly schedules. Once your scheduling data is in Excel format, it can be easily imported into Microsoft Project. The Excel spreadsheet and Microsoft Project column headers must match. Data imports field to field directly from Excel to Project. Simply verify print format and you now have a Microsoft Project schedule based on your EAM system scheduling data.
Tip provided by Dennis K. Williams, CMRP
MRG
http://www.mrginc.net/
Learn more at EAM-2007 The Enterprise Asset Management Summit
March 08, 2007 Is asset lifecycle management driving you round the bend?
Managing and maintaining your key assets throughout their entire lifecycle is critical to your organizations success. Rather than looking at each part of the asset’s lifecycle in isolation or only focusing on the operational phase, your asset management solution should enable a more holistic view. It should help you manage the entire cycle – from initial design and procurement to retirement and scrapping – ensuring that you get the best return for your investment.
Learn more and get your copy of the new Lawson Enterprise Asset Management solution brochure
March 08, 2007 Vibration Analysis Tip
Acceleration v. velocity based vibration monitoring
The application of velocity based vibration monitoring is different from that of acceleration based. It is important to select a sensor that will provide usable data across the range and accommodate the amplitude range of the application.
The majority of rotating machinery runs at 600 cpm to 3600 cpm. The sensor frequency range required to monitor vibration caused by imbalance and reciprocating forces is between 600 cpm and 120,000 cpm (10 Hz to 2000 Hz). For these machines and this type of monitoring, a velocity output sensor is best suited due to its increased sensitivity to low frequency vibration and de-emphasis of high frequency vibration.
With acceleration based vibration monitoring, the sensor has increased sensitivity to higher frequencies. This allows more emphasis on the frequencies which are indicative of bearing and gear mesh condition. However, very high levels of high frequency vibration from impacting gear teeth or metallic impact can overload the range of the accelerometer. In these cases, the velocity sensor is used to de-emphasize the high frequency signals.
In general, velocity sensing is preferred for general condition monitoring. Acceleration monitoring can be used for general bearing condition monitoring. If the accelerometer overloads due to high frequencies, switch to a lower sensitivity sensor or a velocity monitoring sensor.
Tip provided by Wilcoxon Research
http://www.wilcoxon.com
March 08, 2007 Lubrication Tip
Blocked or Plugged Fittings
It is important to check the connection fitting between the constant level oiler and the equipment housing to verify that there is no blockage. When oil becomes oxidized or contaminated, it can easily plug this fitting, which is commonly ¼-inch NPT or smaller. If this occurs, the constant level oiler will not feed, and the oil level in the sump can become dangerously low. This is easy to check by removing the constant level oiler during oil changes / servicing and looking at the fitting opening. If the fitting is plugged use a wire or pipe cleaner to remove the blockage. After removing blockage verify the fitting is free from any loose contaminants prior to installing as these contaminants will get into the lubricant supply.
Tip provided by Trico Corporation
800-558-7008 (USA only)
262-691-9336 (Int’l)
