Search Results for electric motors

This chapter explains how powder metallurgy technologies are being leveraged for the production of automotive components, electric motors, rare-earth permanent magnets, and the infrastructure for high-speed rail transport.

One of the rotor bearings in an electric motor failed, producing excessive vibrate. The bearing was removed and disassembled, revealing craters and bruises on the inner ring raceway and balls along with evidence of melting and burning of metal. Scanning electron microscopy revealed metal particles near the craters, and energy-dispersive x-ray analysis showed that slivers recovered from the grease had the same composition as the bearing raceway and balls. Based on these observations, it was concluded that the bearing failed due to electrostatic discharge, which would have led to seizure if it continued. The report recommends the use of electrically conductive grease and proper grounding practices.

Iron and steel have been the most useful materials to meet the needs of several industries for many decades. Each iron and steel alloy offers unique attributes that make them the best choice for an application. This chapter provides an overview of each ferrous alloy—gray iron, malleable iron, compacted graphite iron (CGI), ductile iron, austempered ductile iron (ADI), and carbon steel and low-alloy steel; its versatile attributes; and its individual applications. A large section of the chapter covers the impact of electric vehicles on the future of the iron and steel castings industry, including discussion on electric vehicle categories and weights; impact of center of gravity on stability and steering; lightweighting incentives; and engineering for improved suspension.

Root cause of failure in automotive electronics cannot be explained by the failure signatures of failed devices. Deeper investigations in these cases reveals that a superimposition of impact factors, which can never be represented by usual qualification testing, caused the failure. This article highlights some of the most frequent early life failure types in automotive applications. It describes some of the critical things to be considered while handling packages and printed circuit board layout. The article also provides information on failure anamnesis that shows how to use history, failure signatures, environmental conditions, regional failure occurrences, user profile issues, and more in the failure analysis process to improve root cause findings.

This chapter discusses the design and operation of hydraulic presses. It begins by describing the role of each major component in a hydraulic system. It then explains the difference between pump-driven and accumulator-driven presses and the types of applications for which are suited. The chapter goes on to describe the load, energy, and time-dependent characteristics of hydraulic presses and the factors that determine accuracy. It also explains how hydraulic presses are used for deep drawing, fine blanking, and hydroforming as well as warm forming and hot stamping operations.

This chapter documents the key findings of an investigation into the failure of an aircraft’s main wheel bearing housing. Using annotated images and a detailed SEM fractograph, it shows what investigators observed that led them to conclude that the flange on one of the hubs broke off due to a combination of fatigue, bending stresses, and wear. It also includes a recommendation to assess the structural integrity of the bearing housing after every 100 h of service using nondestructive techniques.

This chapter covers the friction and wear behaviors of copper alloys. It describes the compositions and forms of copper available and their suitability for applications involving friction, different types of erosion, and adhesive and abrasive wear.

This chapter discusses the use of phase diagrams in alloy design, processing, and performance assessment. The examples cover both ferrous and nonferrous metals and a variety of goals and objectives. The chapter also identifies limitations and pitfalls associated with the use of phase diagrams.

This chapter discusses the design and operation of electromechanical servo-drive presses. It begins by comparing the operating flexibility of servo-press drives with that of their conventional counterparts. It then explains the difference between direct-drive and belt and screw-driven servo presses and describes some of the innovations and improvements made possible with high-torque servo motors. The chapter provides examples of how servo presses are used in blanking, warm forming, and other applications and compares the operating characteristics of two 1100-ton presses, one driven by servo motors, the other by a mechanical crank.

The load-displacement capabilities of a mechanical press are determined largely by the design of its drive mechanism or, more precisely, the linkage through which the drive motor connects to the slide. This chapter discusses the primary types of linkages used and their effect on force, velocity, and stroke profiles. It begins by describing the simplest drive configuration, a crankshaft that connects directly to the slide, and a variation of it that uses eccentric gears to alter the stroke profile. It then discusses the effect of adding a fixed link, knuckle joint, or toggle to the slider-crank mechanism and how gear ratios, component arrangements, and other design parameters affect slide motion. The chapter also explains how to assess load and energy requirements, time-dependent characteristics, and dimensional accuracy and discusses overload protection, shutheight adjustment, and slide counterbalancing as well.