Course Overview

The Ammeters, Meggers and Wheatstone Bridge course is designed for participants familiar with AC/DC theory, electrical safety, and electrical print reading. A basic understanding of electronic devices and circuits is recommended. The course describes megohmmeters, Wheatstone bridges, and clamp-on ammeters. It gives examples of the use of these instruments, identifies their components, and defines their functions. The lessons also describe safety and selection considerations for their use, how to set up the instruments, how to connect them to the systems under test, and how to take and read measurements.

Course Objective

• Explain the formula and how a working knowledge of Ohm’s Law is helpful when analyzing test results.
• Describe, and give an example of, the use of a megger; Define the function of a megger.
• List the causes of damaged insulation; Describe the causes and effects of low resistance readings.
• Identify the basic components of a typical megger; Identify the switches on a digital megger.
• Describe safety considerations when using a megohmmeter.
• List considerations and procedures when selecting, setting up, and reading a megger.
• Define a bridge circuit.
• Identify the components of a Wheatstone bridge.
• Define the function of a Wheatstone bridge.
• Describe how to balance a Wheatstone bridge.
• Describe how to set mechanical and electrical zero on a Wheatstone bridge.
• Describe how to take a reading with a Wheatstone bridge.
• Describe how to interpret a Wheatstone bridge reading.
• Interpret a Wheatstone bridge reading
• Identify the components of a clamp-on ammeter.
• Describe the range function of a clamp-on ammeter.
• Define the function of a clamp-on ammeter.
• Describe safety and selection considerations for using a clamp-on ammeter.
• Define the “”record and lock”” features.
• Describe the procedures for setting up a clamp-on ammeter.
• Describe how to take a reading and modify the range of a clamp-on ammeter.

Included Modules

1. Introduction to Megohmmeters: This is the first lesson in Ammeters, Meggers, and Wheatstone Bridge Course. This lesson explains Ohm’s Law and how it is used when analyzing test results. The basic components, uses, and functions of a megohmmeter are described. Insulation and causes of insulation damage are also covered.
2. Using the Megohmmeter: This is the second lesson in the Ammeters, Meggers, and Wheatstone Bridge Course. This lesson describes safety issues to consider when using a megohmmeter, how to select the correct megger for the job, setup, and the steps necessary to take a megger reading.
3. Wheatstone Bridge: This is the third lesson in the Ammeters, Meggers, and Wheatstone Bridge Course. This lesson explains what a bridge circuit is, the purpose and components of a Wheatstone bridge, and its function.
4. Using a Wheatstone Bridge: This is the fourth lesson in the Ammeters, Meggers, and Wheatstone Bridge Course. This lesson explains how to balance a Wheatstone bridge and the process used to set mechanical and electrical zero. How to interpret the readings of a Wheatstone bridge is also explained.
5. Clamp-on Ammeters: This is the final lesson in the Ammeters, Meggers, and Wheatstone Bridge Course. This lesson presents the components and features and functions of clamp-on ammeters. The lesson also describes safety considerations that should be noted when selecting a clamp-on ammeter. Instruction in the procedures for setting up, taking readings, and modifying the range of a clamp-on ammeter are also covered.