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.

During the qualification campaign of the NIRSpec (near-infrared spectrometer) instrument mechanism, the actuator could not achieve the expected lifetime that had been extended during the development phase. The initial design could not be adapted to the requested number of revolutions during that phase. Consequently the actuator needed to be modified so that the function of the mechanism would not be endangered or, by extension, the overall function of the NIRSpec instrument. The modification included a change of the overall actuator design—internal dimensions, tolerances, materials, lubrication and assembly process—while keeping the interface to the mechanism, mass and function.

One of the driving forces behind the industrial revolution was the invention—more than a century ago—of the electric motor. Its widespread use for all kinds of mechanical motion has made life simpler and has ultimately aided the advancement of humankind. And the advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric motors to new realms that were inconceivable just a mere 30 years ago. Advances in power semiconductors—along with digital controls—have enabled realization of motor drives that are robust and can control position and speed to a high degree of precision. The use of AC motor drives has also resulted in energy savings and improved system efficiency. This paper reviews the development and application of inverter technology to AC motor drives and presents a vision for motor drive technology.

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.

Based on simulation methods and calculation tools developed by the Schaeffler Group and presented in the first part of this paper, three approaches regarding increased efficiency based on rolling bearings are presented.

Permanent-magnet, synchronous-torque motors offer significant advantages on high-energy-consuming and high-dynamic applications.

In order to make better purchasing decisions about centrifuge applications, one must understand the concept of centrifuges and the drives that operate this equipment.

This paper provides an overview of the more common position sensor options and references actual case studies to illustrate the diverse solutions available and the reasons behind some of the decisions. Three cases are used to illustrate the needs of different applications leading to the choice of a particular type of position sensor. The cases reviewed include a gantry crane, wind turbine and aerial cable car.

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.

This article will examine the major materials used to enhance balls to resist aggressive environments and help in selecting the right one.