Introduction

General Applications. The use of electronic equipment in industry has been increasing at a very rapid rate. Electronics has made it possible to automate many industrial processes, thus reducing costs below the cost of human labor to do the same work. A complete summary of the use of electronics in industry is beyond the scope of this handbook; however, the use of electronic apparatus can influence the design and operation of the electric (power) equipment in an industrial plant, and is discussed. The engineer responsible for design and operation of electric equipment will need to consider these influences, some of which are described below.

Electronics has made possible new and more effective safety devices. In addition, with electronics it has become possible to achieve greater accuracy in measurements, to use more precise methods of control, and to provide improved supervision of industrial operations. In most cases, these improved operations have required that the performance of the plant electric system be more reliable, have better regulation, and have improved protective devices.

Electronic controls are used in industry to monitor and control physical quantities within industrial processes. The simplest form of an electronic control system is shown in Fig. 22-1a . It consists of three elements: (1) the process to be monitored or controlled, (2) a transducer, and (3) an indicator. The...