Gearbox vibrations are classified as synchronous or nonsynchronous depending on whether or not they are related to the rotational speed of an internal or connected component. This chapter presents a turbogenerator case study that demonstrates the source of nonsynchronous vibration. It then provides a detailed discussion on spiking vibrations and presents design improvement and reduction of spiking vibrations.

Induction heat treating is used in a wide range of applications. Typical uses, as described in this chapter, include the surface hardening of many types of shafts as well as gears and sprockets and the through-hardening of gripping teeth, cutting edges, and impact zones incorporated into various types of tools and track pins manufactured for off-highway equipment.

This chapter describes case depth and discusses flame hardening, laser heat treatment, electron beam hardening, induction heat treatment, and induction hardening.

Gearbox vibrations can often be dealt with in the field by modifying, replacing, and repositioning components and adjusting operating conditions and control parameters. Every gearbox design, however, eventually reaches a point where problems due to vibration are not so easily addressed. This chapter discusses such a case, that of an epicyclic reducer plagued by subsynchronous vibration, and explains how the gearbox was redesigned, improving lifetime as well as efficiency.

This appendix provides a list of books and technical papers utilized as reference material during the development of this book.

This chapter begins with a review of some of the terms used in the gear industry to describe the design of gears and gear geometries. It then discusses the types of gears that operate on parallel shafts, intersecting shafts, and nonparallel and nonintersecting shafts. Next, the processes involved in the selection of gear are discussed, followed by information on the basic stresses applied to a gear tooth, the strength of a gear tooth, and the most widely used gear materials. Further, the chapter briefly reviews gear manufacturing methods and the heat treating processing steps including prehardening processes, through hardening, and case hardening processes.

This chapter details the vibration limits for gearboxes. It focuses on critical speed and peak load. The chapter presents vibration measurement and analysis, which provides a quick and relatively inexpensive way to detect and identify mechanical problems before they become more serious and costly.

Coal-based thermal power plants play a major role in the welfare of many nations and the overall global economy. This chapter describes the basic equipment requirements and operating principles of thermal power plants, particularly subcritical, supercritical, and ultra-supercritical types.

In the case of gearboxes, vibration is the primary mode of failure even at the mid-range of operating speeds. Avoiding such failures requires an understanding of gearbox design, vibration theory, and material properties. This chapter details sources and types of gearbox vibrations; characteristics of gearbox vibrations; fundamentals of periodic vibrations; and vibration theory. It provides housing design for single-stage offset parallel gearboxes, high-speed gearboxes, and epicyclic gearboxes. The chapter then provides an analysis and selection of design factors for vibration reduction. It presents five types of gear tooth geometry errors. The chapter also focuses on gear quality inspection and on bearing-induced vibrations.

This appendix provides practical information on induction coils and how they are made. It discusses soldering methods, preferred materials, design challenges, and best practices and procedures. It also discusses the design, construction, and application of magnetic flux concentrators and the growing use of computer simulation.

The detailed heating requirements for specific applications must be considered before construction and implementation of any induction heating process. These requirements may include considerations such as type of heating, throughput and heating time, workpiece material, peak temperature, and so forth. The major applications of induction technology include through heating, surface heating (for surface heat treatment), metal melting, welding, brazing, and soldering. This chapter summarizes the selection of equipment and related design considerations for these applications.

This chapter presents the purpose, design, and function of a gear. It also presents the basic stresses applied to a gear tooth. The chapter provides an overview on the bending strength and characteristics of the gear tooth.

Electromagnetic induction, or simply "induction," is a method of heating electrically conductive materials such as metals. It is commonly used for heating workpieces prior to metalworking and in heat treating, welding, and melting. This technique also lends itself to various other applications involving packaging and curing of resins and coatings. This chapter provides a brief review of the history of induction heating and discusses its applications and advantages.

The cyclic nature of gearbox vibration lends itself well to the analysis in the frequency domain where the effects of a gear mesh, bearing defects, and other sources of vibration are effectively set apart, making it much easier to identify and correct the underlying causes of vibration. This chapter presents spectral maps that show how gearbox vibrations change with the rotational speed of components. It then explains how to identify the sources of vibration in a high-speed gearbox. The chapter also discusses other errors including backlash, ghost frequencies, unbalance, misalignment, mechanical looseness, and index variation form errors. It also presents the calculation of gear frequencies on gearbox vibration spectra and the influence of operating conditions.