Switches, Coils, and Overloads (A8006)

Learn types, function, and industry usage of switches and coils, as well as testing and verification of malfunctions.

Prerequisites

Switches, Coils, and Overloads is designed for participants familiar with AC and DC theory, electrical safety, electrical print reading, electrical connections, and the proper use of electrical test instruments. An understanding of the operation of control circuits and components, such as switches, relays, fuses, and circuit breakers is recommended.

Description

This lesson describes switches, coils and overloads, as well as explains the type and operation of switches and overload relays. It will also cover the testing of switches and coils. Participants will learn the proper way to verify that a circuit is de-energized, and how to determine component malfunctions by use of circuit diagrams, manufacturer??s literature and continuity checks.

Objectives

Switches, Coils, and Overloads provides users with the knowledge to do the following:
Explain what types of switches are used in industry and know how to tell if they are functioning properly. Know how to test coils and how to test and replace overload relays. Explain the concept of poles and throws and describe the operation of momentary and maintained push-button switches. Describe how selector switches work. Describe rotary switches and explain how to read a switch connection diagram. Perform a continuity check on a push-button switch and remove and replace a defective push-button contact block. Learn how to check coils for overheating and breaks in the wire winding. Explain how an overload relay protects a motor and describe how a bimetallic thermal overload relay works. Describe how a melting-alloy thermal overload relay works and explain its heat storage characteristics. Describe magnetic and electronic overload relays. Describe the common problems of thermal overload relays. Install a thermal overload relay in a starter.