TABLE OF CONTENTS This chapter concentrates on the electrical equipment associated with the refrigeration system. It focuses on controlling the electrical supply to the system and on electrical and/or electronic sensors and actuators. Because the full range of electrical topics is so vast, a selection has been made, as illustrated in Fig. 14.1, such that the subjects treated in this chapter are those most intimately connected with the refrigeration system. Those topics not covered or only mentioned in passing include, for example, electrical circuits (single- and three-phase, wye and delta), conductor sizing, circuit protection, power factors and their corrections, and transformers. Another important body of knowledge that is not covered is that of motors the types of industrial motors and their characteristics.
The electrical principles that will be explained are those related to controlling the power to electric motors and other equipment and the electrical types of instrumentation and actuators. The first major topic presented will be ladder diagrams, which are the widely accepted means of showing control logic and are the plans followed by electricians. Means of executing ladder diagrams include electromechanical relays, programmable controllers, and computer controllers. Instruments providing visual indications (pressure gauges, thermometers, etc.) are standard and should continue to be installed. The shift in recent years to electronic and/or computer control, however, stimulates a greater need for electric and electronic sensors, transducers, and actuators. These devices will be explained in the latter...
