Archive | Bearings

223

7:05 pm
July 12, 2017
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Store Your Bearings Properly

Metal bearings with random rotation and scale.Bearings are a critical part of the design and function of most mechanical equipment. Sadly, due to improper selection, storage, and installation, the majority of these components never reach their intended design life. Consequences for a plant from these situations can include compromised equipment operation, lost capacity, and increased costs.

A recent post on the Ludeca (ludeca.com, Doral, FL) blog urged readers not to condemn their equipment to death through improper bearing storage. The author, Trent Phillips, CRL, CMRP, offered a number of best-practice must-dos and don’ts to help facilities ensure bearing reliability.

— Jane Alexander, Managing Editor

Bearing storage must-dos

Do store bearings in a clean, dry, low-humidity environment. Moisture from the environment, work gloves, and other sources can result in corrosion and/or etched sections that create fatigue on a bearing. Avoid storage near direct sunlight, air conditioners, or vents.

• Do eliminate the possibility of shock/vibration during handling and storage.

• Do store bearings on pallets or shelves in areas that aren’t subjected to high humidity or sudden or severe environmental changes.

• Do store bearings flat and never stack them. Lubrication and anti-corrosion material could squeeze out of stacked bearings.

• Do (always) lay bearings on clean, dry paper when handling.

• Do keep bearings away from sources of magnetism.

randmBearing storage don’ts

• Don’t store bearings on the floor. Doing so will introduce contamination, moisture, and vibration/shock.

• Don’t remove bearings from cartons/crates or protective wrappings until just prior to installation in a machine. The exception may be bearings in wooden crates, as they could attract moisture.

• Don’t clean bearings with cotton or similar materials that can leave dust and/or contamination behind. Use lint-free materials.

• Don’t handle bearings with dirty, oily, or moist hands.

• Don’t nick or scratch bearing surfaces.

• Don’t remove any lubrication from a new bearing. Lubricants in stored bearings will deteriorate over time. The bearing manufacturer should specify shelf-life limits. These dates should be noted on the packaging and monitored to help ensure bearings are fit for use when needed. MT

Visual Inspections

Proper storage techniques are just part of the reliability picture when it comes to bearings. According to Trent Phillips, the following visual inspections of bearing integrity should be completed periodically on stored bearings, and just prior to putting them into service:

Examine packaging for indications that the bearing could have been damaged during shipment or storage. The item should be discarded or returned to the supplier if signs of damage are found.

Examine the grease or oil for evidence of hardening, caking, discoloration, separation, and other problems. Re-lubrication for continued storage or replacement maybe required.

Trent Phillips, CRL, CMRP, is global reliability leader with Atlanta-based Novelis (novelis.com). To read more of his insight on Ludeca’s website (ludeca.com), including Part 1 of the two-part post “Has Your Equipment Been Condemned to Death?” on which this Reliability + Maintenance Center page is based, go to ludeca.com/blog.

14

5:01 pm
June 22, 2017
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Trailing Edge Cooling Technology

1703mtprod11pThe company has patented its trailing edge cooling technology that increases heat transfer in tilting-pad bearings to expand bearing operating limits. The design features grooves in the trailing edge face of the tilting pad and a spray bar adjacent to the trailing edge to deliver cooling flow. The grooves in the trailing edge face increase the surface area and allow the lubricant to penetrate deeper into the pad for greater cooling effect. The flow supplied to the trailing edge is a portion of the flow already being supplied to lubricate the bearing for hydrodynamic operation.
Waukesha Bearings
Pewaukee, WI
waukeshabearings.com

698

2:02 pm
September 15, 2016
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Handle Bearings With Care

1609rmcbearings01pModern rolling contact bearings, when installed and lubricated properly, can outlast the machines in which they function. In practice, though, less than 10% of all rolling-element bearings reach their full design life. As for the others, 30% of premature failures can be attributed to incorrect installation or damage done during (or prior to) installation. Continue Reading →

65

9:00 am
July 18, 2016
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Interchangeable Coupling Line

1607mtprod21pThe company’s line of L-Jaw couplings includes a range of bore sizes and aluminum and stainless-steel hubs. The line is part-for-part interchangeable with industry-standard designs. An interchange guide is available. A wide range of sizes is offered with torque ratings to 6,228 in. lb. and bore sizes to 2 7/8-in. dia. Couplings can accommodate as much as 1 in. of angular misalignment and have an operating temperature range of –60 to 250 F.
TB Wood’s Inc.
Chambersburg, PA
tbwoods.com

253

4:02 pm
April 6, 2016
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White Paper | Predictive Analytics for Power Plants

Power producers are encountering many changes to their business model and remote monitoring — along with predictive analytics — is an attractive value proposition to end users. GE’s Predix platform offers SmartSignal, a software system that models historian plant data and constructs anomaly data to measure current conditions at a power plant. The modeling is called Variable Similarity-Based Modeling (VBM) technology and can be teamed up with GE’s Industrial Performance and Reliability Center (IPRC) to provide a comprehensive reliability solution.

This white paper introduces key concepts from the SmartSignal software and examines three power plant case studies.

Read White Paper >>

Maintenance Technology’s IIoT page | Find out more about edge computing and other proactive maintenance approaches. 

462

4:50 pm
February 24, 2016
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Prevent Motor-Bearing Failures

Learn the latest on the top five causes of failed motor bearings to help stop these problems in their tracks.

By examining a failed motor bearing and understanding the clues that various types of damage often produce, you can keep these problems from plaguing your motor fleet in the future.

By examining a failed motor bearing and understanding the clues that various types of damage often produce, you can keep these problems from plaguing your motor fleet in the future.


According to the bearing experts at SKF (Gothenburg, Sweden, and Lansdale, PA) these five damage mechanisms are the most common causes of motor-bearing failures. Understanding them as you examine a failed bearing can help you prevent their recurrence.

Electrical erosion
Electric erosion (arcing) can occur when a current passes from one ring to the other through the rolling elements of a bearing. While the extent of the damage depends on the amount of energy and its duration, the result is usually the same: pitting damage to the rolling elements and raceways, rapid degradation of the lubricant, and premature bearing failure. To prevent damage from electric-current passage, an electrically insulated bearing at the non-drive end is usually installed.

Inadequate lubrication and contamination
If the lubricant film between a bearing’s rolling elements and raceways is too thin due to inadequate viscosity or contamination, metal-to-metal contact occurs. Check first whether the appropriate lubricant is being used and that re-greasing intervals and quantity are sufficient for the application. If the lubricant contains contaminants, check the seals to determine whether they should be replaced or upgraded. In some cases, depending on the application, a lubricant with a higher viscosity may be needed to increase the oil-film thickness.

Damage from vibration
Motors transported without the rotor shaft held securely in place can be subjected to vibrations within the bearing clearance that could damage these components. Similarly, if a motor is at a standstill and subjected to external vibrations over a period of time, its bearings can also be damaged. To prevent these problems, secure the bearings during transport in the following manner: Lock the shaft axially using a flat steel bent in a U-shape, while carefully preloading the ball bearing at the non-drive end. Then radially lock the bearing at the drive end with a strap. In case of prolonged periods of standstill, turn the shaft from time to time.

Damage caused by improper installation and set-up
Common mistakes in installation include using a hammer or similar tool to mount a coupling half or belt pulley onto a shaft; misalignment; imbalance; excessive belt tension; and incorrect mounting resulting in overloading. To prevent these problems, use precision instruments such as shaft-alignment tools and vibration analyzers and other appropriate tools and methods when mounting bearings.

Insufficient bearing load Bearings always need to have a minimum load to function well. If they don’t, damage will appear as smearing on the rolling elements and raceways. To prevent these problems, be sure to apply a sufficiently large external load to the bearings. This is crucial with cylindrical roller bearings, since they are typically used to accommodate heavier loads. (This, however, does not apply to preloaded bearings.)

Source
SKF is s a global supplier of bearings, seals, mechatronics, lubrication systems, and services that include technical support, maintenance and reliability services, and engineering consulting and training. For more information on motor bearings and other technologies and topics, visit skf.com.

202

9:08 pm
February 18, 2016
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High-Definition Vibration Enveloping

1603mtprod20pHD Enveloping is a high-definition vibration enveloping technique for detection of early-stage gear and bearing faults. A complement to traditional vibration analysis, the method detects, at a very early stage, machine problems that are generally difficult to find in good time with conventional non-enveloping techniques. Significantly extending the planning horizon for predictive maintenance, the method is said to be a boost to maintenance efficiency. The technique can be used with existing vibration transducer installations and integrates into existing industrial infrastructures while monitoring applications in the 15,000 to 20,000 rpm range.

The unit of measurement is HD Real Peak, a scalar value expressed in decibels. Representing the true amplitude levels found in the envelope signal, HD Real Peak is the primary value to use for determining the severity of a given damage. It is also used for triggering alarms. Using order tracking and symptom enhancement, applying FFT on the signal is very useful to determine the source of the signal. Spectrums and time signals provide a snapshot of machine condition to give the maintenance department a heads-up on potential problems. Straightforward setup uses a set of predefined filters, each designed to detect damages or anomalies in different stages of development.
SPM Instrument
Eugene, OR
spminstrument.us

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