June 07, 2007 Predictive Maintenance Tip
Hump Effects of a New PdM Program
The impact of application of new PdM Technologies can create some misleading initial results.
Problems that have been “lived with” many now be subject to recommendations from PdM specialists in early phases of technology introduction on an asset.
A “hump” in work requests causes a “hump” in maintenance cost due to purchase of replacement parts, consumables and perhaps some outside services.
Make sure PdM program sponsors and managers understand that cost may go up before they come down.
Tip excerpted from “Predictive Maintenance Management” Course workbook by Jack Nicholas Jr. available at
http://www.masteringmaintenance.com
Register for Jack Nicholas’s PdM Managers Web Workshop June 29 - 11 am
June 07, 2007 Vibration Analysis Tip
Frequency Analysis Tip
Gear analysis requires knowledge of the gear tooth counts to access the vibration signals originating in the mesh from other signals picked up by the transducer. The tooth counts ensure that the gear mesh frequency can be determined, and will allow the analyst to pick out problematic gears by inspection of the modulation in the signal(s). These modulations will produce sideband peaks around the meshing frequency and their harmonics. Another less emphasized analysis parameter is the direction in which the gearbox data is collected. It’s always a good idea to collect data in multiple directions, however knowledge of the gear design (spiral, bevel, herringbone, spur, etc.,) can be helpful as far as indicating the dominant direction of the gear mesh reaction forces. Sometimes a measurement in the axial plane may be the best trending location.
Tip by Dan Ambre, P.E.
Full Spectrum Diagnostics, PLLC
Phone: 763-577-9959
Email:
June 07, 2007 IRTalk.com by Snell Infrared
IRTalk.com is an online community of infrared professionals that welcomes everyone regardless of their equipment preference, training, experience, or applications. Whether you are a maintenance technician, reliability engineer, electrical contractor, building inspector, weatherization professional, infrared service provider, or just want to know more about infrared, IRTalk.com is the place to learn from those who are active in the industry.
June 07, 2007 CMMS/EAM Tip
Setting up CMMS Should I use Failure Codes or Failure Modes?
Many CMMS have set up squawk codes with hundreds of items to pick from. Often the cause most called for is “other”. This is frustrating and time consuming for Reliability Engineers trying to analyse failure characteristics of equipment.
So a change in mindset is required.
Don’t try and capture causes- capture the failure mode specific to the equipment.
A specific time to failure data set can be analysed in modern Weibull packages in seconds.
This allows the engineer to spend a greater proportion of his time on interpretation and decision making.
Tip provided by ARMS Reliability Engineers
Find Out More About Weibull analysis and other maintenance optimisation
June 07, 2007 Infrared Tip
Thermographers, Tag Your Hot Spots
It’s such a simple thing to do, but how many of us don’t tag the hot spots we find? Some of the reasons for tagging are:
Tagging is:
• An Identifier. It identifies to others that a problem exists.
• A Reminder. It is a very visual reminder to take care of this problem.
• A Warning. It warns others there may be added danger at this location and to exercise additional caution before opening the enclosure.
You can buy the tags or make your own like we did at Johns Manville, McPherson Kansas. Making your own has some advantages over generic tags such as you can customize and change the information you put on the tags. Information you would want to include on your tag might be such things as the:
• Equipment Name
• Current Load
• Severity
• Date
• Delta T
• Brief Description of Problem
• Thermographers Name(s)
No matter where you are in your program development, just starting or not. Maybe you are having contract Thermographers shoot your equipment.
Whatever is the case, by all means always TAG your hot spots…
Reader tip provided by Nick Bohonik
Johns Manville
Reliability - Thermography Group
Coffeeville Kansas
(Winners of the 2006 Uptime Best Infrared Program Award)
Thanks Nick - your stainless steel Maintenance-Tips coffee mug is on the on the way.
June 07, 2007 Increase awareness with online surveillance!
Vibration analysis, the industry-preferred technology, allows accurate machinery health monitoring and assessment.
One way to implement a vibration analysis program utilizes continuous online surveillance especially in unsafe and hard to reach areas to minimize production loss and drive down the overall cost of maintenance.
In order to provide the clearest possible picture of your machine operating condition, the vbOnline measures and records many different process parameters. This gives you the ability to trend and trigger alarms to assess not only vibration related faults, but also how your machines perform on a continuous basis.
Commtest – Join the Revolution
For more information please call 865-588-2946 or…
June 07, 2007 Motor Testing Tip
On-line testing and temperature
When doing on-line testing, the parameters that the tester reads change when the machine is cold (recent start-up after long stop period)or when the machine has been running for a period of time. The larger the machine under test, the larger the time for the components (iron, copper and insulation) to reach a stable, operating temperature. Thus, it is important to let the system stabilize for a conservative period of time before running any tests on it.
Among the components of a rotating machine that change due to heat is the Line-to-Line resistance in the copper. This factor alone will introduce an error of about 1% to 2%. On a 5HP motor operating an axial FAN, about 20 minutes are needed before capturing any data.
On the other end, if a machine is submitted to frequent starts and stops the heat build-up will be higher than normal operating temperature. This is due to the stator difficulty on dissipating heat. This would skewed results too. Be mindful of motor (and system) temperatures when testing on-line.
Tip provided by Baker Instrument Company
(970) 282-1200
(800) 752-8272
http://www.bakerinst.com
June 07, 2007 Root Cause Analysis (RCA) Tip
Avoiding a disconnected RCA
When conducting Root Cause Analysis investigators should always be at the failure scene at the time the equipment is opened. The benefit to the investigation is enormous because when equipment is disassembled the evidence is removed and many times discarded quickly in an effort to get back to production. The advantage to the investigator is from a positional view of the failed area. When you are there the investigative process of mapping the failure scene can be accomplished accurately using video, digital pictures, and drawings. This becomes valuable later when the RCA team meets to discuss the possible failure scenarios based on the failure scene. If you have to rely on third party information it is likely skewed from the original scene. This can slow your RCA down because now you have to put the initial first viewing together based on people’s memories before you can continue your analysis. If what you are told is incorrect then your RCA is started using non-factual information and could end with non-factual conclusions.
Tip provided by Mark Latino
Reliability Center Inc.
http://www.reliability.com
