Articles About rating


Webinar: Advanced Mainshaft Bearing Solutions for Wind Turbines

Mainshaft bearings inside wind turbines are subjected to extremely harsh operating conditions that result in failure patterns which include surface-initiated fatigue, abrasive wear and uneven internal load distribution. This webinar will introduce you to the latest engineering advancements in spherical roller bearing design, including solutions that allow potentially damaging thrust to be safely transferred through the bearing to the housing support. The resulting reduction in torque, friction and heat significantly improves the overall efficiency of the system, thereby enabling the wind turbine to generate more power – more reliably! Webinar Courtesy of Schaeffler

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1 Desktop Engineering - How to Calculate Dynamic and Static Load Ratings (February 2015)

When comparing bearing suppliers, engineers are often left with few options other than to compare dynamic load ratings and corresponding life calculations. Of course, we can look at steel and manufacturing quality; but if we are comparing sources of similar quality, those items may not provide a large contrast. It often surprises people to learn that bearing capacities are calculated values, not tested values. Lately, however, a trend is emerging for bearing suppliers to increase their ratings for higher performance bearings that have premium features such as higher quality steel and specilaized heat treatment. Bearing companies are under intense competitive pressure to make every feature add to the dynamic capacity of their bearings because it is very well understood that an increase in capacity adds to the bottom line.

2 Not All Thin-Section Bearings Are Created Equal (February 2011)

American Bearing Manufacturers Association (ABMA) Standard 9 and ISO 281 give equations for calculating the basic dynamic radial load rating for ball bearings. These equations are based on a number of assumptions, many of which are not valid for thin-section bearings. (Thin-section bearings are described in ABMA standard 26.2.) Nevertheless, many thin-section bearing catalogs report load ratings based on these equations. Kaydon has developed a new method for calculating the dynamic radial load rating for thin-section ball bearings. The new method uses the contact stress and the number of stress-cycles-per-revolution to calculate the capacity. The new numbers are based on five years of actual test results. These equations can also be used to calculate the dynamic radial load rating for four-point contact ball bearings, which are not covered in ABMA standard 9 or ISO 281.

3 Rating of Asymmetric Tooth Gears (April 2016)

Asymmetric tooth gears and their rating are not described by existing gear design standards. Presented is a rating approach for asymmetric tooth gears by their bending and contact stress levels, in comparison with symmetric tooth gears, whose rating are defined by standards. This approach applies finite element analysis (FEA) for bending stress definition and the Hertzian equation for contact stress definition. It defines equivalency factors for practical asymmetric tooth gear design and rating. This paper illustrates the rating of asymmetric tooth gears with numerical examples.

4 The Modified Life Rating of Rolling Bearings: A Criterion for Gearbox Design and Reliability Optimization (March 2015)

Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

5 Load Ratings & Bearing Life (March 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools.

6 Gear- or Actuator-Driven, These Bots Are Cutting-Edge (October 2008)

Robots are everywhere these days— bots in the factory, bots in space, bots at the airport, bots in the movies and much, much more. But robots in the operating room?

7 Ask the Expert (February 2015)

Questions by readers answered by Experts in the field.

8 The Fundamentals of Specifying and Selecting Gear Drives (December 2012)

Gear drives deliver power to industrial equipment such as bulk material conveyors, mixers, pumps and paper mills. The reliability that translates into greater uptime and profitability begins by specifying and selecting the proper drives for these critical applications.

9 Critical Factors for Proper Product Selection and Sizing (August 2014)

"Well begun is half done," a quote that most reference materials attribute to Aristotle, certainly applies when selecting mechanical power transmission products. A selection process that is well thought out at the start can ensure that the product selected will be properly sized and appropriate to the application at hand.

10 A Major Step Forward in Life Modeling (March 2017)

The SKF Generalized Bearing Life Model is (GBLM) an innovative new bearing rating life model that is designed to help engineers calculate bearing rating life in a more realistic manner. The new model is a major step forward for the industry and will play an important role in enabling OEMs and end users to better match bearings and applications, resulting in improved machine life and reduced operating costs.

11 Power Generating Play (February 2010)

Never has generating alternative sources of energy been so fun. All that excess energy children have bottled up now helps power lighting for remote African villages.

12 Premature Bearing Failures in Wind Gearboxes and White Etching Cracks (October 2014)

Wind turbine gearboxes are subjected to a wide variety of operating conditions, some of which may push the bearings beyond their limits. Damage may be done to the bearings, resulting in a specific premature failure mode known as white etching cracks (WEC), sometimes called brittle, short-life, early, abnormal or white structured flaking (WSF). Measures to make the bearings more robust in these operating conditions are discussed in this article.

13 Often Overlooked, Lubricants Can Help Lower Energy Consumption (December 2011)

It is a simple fact: better lubrication can lead to dramatic energy savings and an improved bottom line. This ought to interest any plant manager who is looking for ways to reduce operating costs, and it is especially significant at a time when stricter government regulations are in direct contradiction to reducing costs. Lubrication reliability is the solution; this article will describe how manufacturing plants can use “lubrication reliability best-practices” to reduce their energy consumption, emissions and operating costs—all at the same time.

14 What Lubrication Method Should I Use (April 2016)

in the performance and life of a rolling element bearing. Less than 10 percent of bearings reach their theoretical L10 life, and poor lubrication can be attributed to 80 percent of those that fall short. Ideally, a lubricant forms a film layer between moving components in a bearing, separating moving parts, minimizing friction and preventing wear between balls or rollers, raceways and retainers. Lubricants also protect metal surfaces from corrosion and moisture, dissipate heat and can even prevent the ingress of contaminants.

15 The To-Do List (April 2016)

Lubrication management should be standard operating procedure at any manufacturing facility. Vital to both operational and maintenance personnel, a strong, coherent and specific lubrication program will have lasting results in machine efficiency and maintenance. Of course, even those with the best intentions can’t always keep up with the challenges presented day-to-day on the manufacturing floor. Thankfully, PTE is here to help with eight steps to selecting, storing, analyzing and managing your lubrication requirements.

16 Counterfeit Consequences (February 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools. Additionally, our new Field Notes section on page 34 will feature field reports from BSA’s Certified Bearing Specialists.

17 Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life (September 2015)

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings.

18 Baldor Basics: Motors (March 2017)

This issue our Baldor Basics series continues with the topics of motor temperature ratings and metric motors.

19 Analyzing the Poultry Process (June 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools.

20 Setting Techniques for Tapered Roller Bearings (September 2015)

Tapered roller bearings can be set at initial machine assembly to any desired axial or radial clearance. This unique feature enables a designer to control bearings to meet anticipated application operating conditions, and thereby provide optimum bearing and system performance.

21 Timing Belts and Pulleys - Operations (December 2016)

Synchronous drives are especially well-suited for low-speed, high-torque applications. Their positive driving nature prevents potential slippage associated with V-belt drives, and even allows significantly greater torque carrying capability. Small pitch synchronous drives operating at speeds of 50 ft/min (0.25 m/s) or less are considered to be low-speed. Care should be taken in the drive selection process as stall and peak torques can sometimes be very high. While intermittent peak torques can often be carried by synchronous drives without special considerations, high cyclic peak torque loading should be carefully reviewed.

22 Ceramic Bearings for Water Processing, Water Filtration and Liquid Handling Applications (October 2016)

Bearings are an essential component in the majority of mechanical designs and equipment. It is important to consider the most effective materials when designing industrial machinery, especially in applications where water or other liquids are present. Many materials will be unable to overcome the challenges associated with operating in a wet or corrosive environment.

23 Mining for Solutions (September 2016)

Increasing pressure on many fronts is compelling mine operators to thoroughly examine every phase of their operations. Fluctuating demand that whipsaws mineral prices, government-imposed environmental regulations and rising operating costs related to maintenance downtime all pose serious challenges for the mining sector. Add pressure from customers and stakeholders for more sustainable operations as well as union demands for higher wages, and you have a scenario that requires mine operators to exercise every possible option to achieve more efficient operations.

24 Engineering Showcase - Gears and Gear Drives (September 2018)

Machinists Inc. is integrating the machinery, equipment and know-how of The Gear Works-Seattle Inc.

25 Lightweight, Highly Efficient Drive System (February 2017)

This paper presents a joint project conducted by Ashwoods Electric Motors and Oerlikon Fairfield that uses planetary drives with an integrated electric motor. Current solutions used in production of off-highway vehicles rely upon large, heavy and inefficient brushed DC or induction motors, coupled to a planetary gearbox. This presents a number of challenges to the vehicle designers such as: limited vehicle range, limited space around the motor/drivetrain, and motor durability. The proposed integrated system utilizes an Oerlikon Fairfield Torque Hub, widely used in off-highway vehicles, and the Ashwoods first-to-market, interior permanent magnet motor. How these products are integrated, i.e. incorporating a brake solution, represents a market-changing product. Using interior permanent magnet (IPM) technology in the motor design means the motor can be up to 70% lighter, 70% smaller and 20% more efficient than traditional motors used in off-highway traction applications.

26 Rolling Bearings in High-Speed Passenger Traffic (June 2012)

Passenger transport today moves significantly faster than ever before, often operating on separate tracks especially designed for high-speed trains. Accordingly, high-speed rolling bearings are very important components in the bogies of trains today. Maximum train speeds currently reach 380 km/h (236 mph) in the latest high-speed applications - 80% higher than in the earlier days of high-speed traffic. This paper presents two application examples of modern, high-speed traffic, together with some typical bearing arrangements and housings. It provides insight regarding measures taken in the bearing industry to meet the requirements of contemporary, high-speed traffic, and it cites important standards and regulations applicable for - but not restricted to - European applications. To be precise, the focus here is on journal bearings; information on traction motor bearings, transmission bearings and housings is included, but described in less detail.

27 Meet the Dustbot - A New Spin on Waste Management (October 2009)

Scientists have been hard at work creating a robotic system with the capabilities to sweep and collect garbage in urban environments. This real-world Wall-E is known as the DustBot, aimed at designing, developing, testing and demonstrating a system for improving the management of urban hygiene.

28 Reducing Electricity Cost through Use of Premium Efficiency Motors (February 2010)

motors with premium efficiency counterparts presents businesses with a significant opportunity to reduce operating costs. A comparison between premium and standard efficiency motors from 0.25 to 10 horsepower is conducted; comparisons of full-load efficiencies are shown, and estimated payback periods are calculated. Methods for calculating the yearly kilowatt-hour consumption and yearly cost savings of premium efficiency motors for this horsepower range are also given. The cost advantages of premium efficiency motors are summarized, and relevant examples of real world cost savings are shown.

29 Motor System Reliability Considerations for Cost-Effective Purchasing Decisions (June 2008)

OEMs can minimize the cost of ownership by using highly efficient motors and recognizing when unreliable motors are driving up the operating costs of their applications.

30 Motorsports in Motion (February 2008)

KD-Rig Puts Accelerating Developments International in Limelight

31 Predictive Maintenance - There Is an App for That (June 2013)

Implementing a predictive maintenance (PM) program can be tough. Despite its proven success, many companies have been operating the same way for over 50 years and don’t know where to start. Understanding where to start and where to focus is critical. The intention of this article is to give insight to start and sustain an effective program using today’s technology and devices.

32 High-Performance Industrial Gear Lubricants for Optimum Reliability (October 2010)

In recent years, gearbox technology has advanced and original equipment manufacturers (OEMs) have specified required gear oils to meet the lubrication requirements of these new designs. Modern gearboxes operate under severe conditions while maintaining their reliability to ensure end-user productivity. The latest generation of industrial gear lubricants can provide enhanced performance—even under extreme operating conditions—for optimal reliability and reduced cost of operation.

33 Airport Baggage Handling: Queue Conveyor Design from a Gearmotor Perspective (February 2011)

The primary driver of an airport baggage handling queue conveyor must be able to operate under increasingly demanding operating conditions, including frequent starting and stopping. The selection of the primary driver of the queue conveyor is dependent on multiple criteria, including dimensional requirements and durability characteristics.

34 Solar Power Turns a Corner (April 2014)

According to GTM Research and the Solar Energy Industries Association (SEIA), photovoltaic (PV) installations increased 41 percent from 2012 to 2013. Additionally, 410 MW of concentrated solar power came online in 2013. Solar was the second-largest source of new electricity generating capacity in the United States.

35 Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes (March 2014)

A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. This article presents field experience from operating wind turbines that compares the performance of through-hardened and carburized materials. It reveals that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. The field experience further shows that a carburized bearing with a core having low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.

36 How to Spec a Mill Gear (February 2014)

This paper outlines the design considerations that go into construction of a drive system in order to explain the importance of specific data, why it is required, and where design freedom is necessary. Apart from loads and speeds, interface dimensions and site specific conditions are also needed. Deciding up front which gear rating practice to select can affect the torque capacity of the drive train by ~15%.

37 A Focus on the Future at Pack Expo 2013 (October 2013)

More than 27,000 packaging and processing professionals attended Pack Expo 2013 in Las Vegas from September 23–25. In addition to launching new products, creating brand awareness, achieving sustainability goals and generating new business contacts, Pack Expo was an opportunity to engage the next generation of workers in packaging, robotics and processing applications.

38 Load Capacity and Efficiency of Grease-Lubricated Worm Gears (September 2014)

Varying installation requirements for worm gears, as, for example, when used in modular gear systems, can necessitate grease lubrication - especially when adequate sealing for oil lubrication would be too complex. Such worm gears are being increasingly used in outside applications such as solar power plants and slew drives. While knowledge about the operating conditions is often appropriate, the basic understanding for load capacity and efficiency under grease lubrication is quite poor. Investigations done at FZG and sponsored by FVA/AiF are shown here to give an impression of the basic factors of load capacity and efficiency. The results of the investigation indicate a satisfying quality of calculations on heat, load capacity and efficiency based on characteristic parameters of the base oil with only slight modifications to the methodology known from DIN 3996 or ISO TR 14521.

News Items About rating

1 Warner Linear Actuators Receive IP69K Rating (March 20, 2015)
Warner Linear recently announced that select linear actuators and controls received the IP69K rating, the highest rating available for pr...

2 XP100 Designed for Hazardous Operating Environments (May 31, 2011)
Siemens Industry, Inc. recently introduced the XP100 (1-300 hp), designed specifically for hazardous operating environments such as the p...

3 Kaman Distribution Announces New Automation, Control & Energy Operating Unit (September 24, 2015)
Kaman Distribution recently announced the formation of Kaman Automation, Control & Energy, a new operating unit that is said to be th...

4 NFPA Webinar Looks at Pneumatic Flow Rating (August 21, 2012)
Designers of pneumatic systems will have the opportunity to learn how to use more accurate flow rating data to design more efficient pneu...

5 VT Drive Saves Energy and Operating Costs (December 8, 2010)
Danfoss recently introduced the VLT Automation VT Drive. This drive is specifically engineered to save energy, reduce up front and o...

6 Romax Appoints Chief Operating Officer (April 29, 2010)
Romax Technology Limited, a technical consultancy providing design and analysis services for gearboxes, bearings and drivetrains is pleas...

7 Bison Gear’s Hollow Shaft Gearmotor Doubles Continuous Torque Ratings (March 10, 2006)
Bison Gear’s new 562 series hollow shaft gearmotor offers increased low speed center distance coupled with greater clearance for wid...

8 Maxon Releases Heavy Duty Motor for Extreme Operating Conditions (December 23, 2010)
Maxon motor recently launched its EC22 HD (heavy duty) motor, a 22 mm-diameter brushless motor developed for the exceptionally high requi...

9 Parsons Peebles Appoints Robertson Chief Operating Officer (October 6, 2016)
Parsons Peebles is pleased to announce the appointment of Graeme Robertson who joined the company as COO, on October 3, 2016. This appoin...

10 Timken Deep Groove Ball Bearings Keep Equipment Operating Smoothly (November 22, 2017)
A full range of metric deep groove ball bearings is now available from The Timken Company. The portfolio includes standard, thin section,...

11 Siemens Supports World's Largest Concentrating Solar Power Plant (July 18, 2012)
Siemens Industry, Inc. has begun shipping drives to support a multi-million contract with Abengoa, an international developer of renewabl...

12 Lenze i500 Frequency Inverters Achieve IE2 Rating without Sacrificing Versatility (October 27, 2015)
Lenze recently announced the launch of its new line of fully scalable i500 frequency inverters. The functions and power of the new range...