Contact Resistance Testing

Summary

This 29-minute DVD describes how abnormal contact resistance in devices such as circuit breakers and disconnect switches can have an adverse effect on power system operation. It shows how contact resistance testing can be used to help determine the condition of switching equipment, and how it may perform under normal and abnormal operating conditions. The DVD shows some of the most common types of contact resistance test equipment, several examples of how test connections are made, how to perform contact resistance testing, and how to read the results of these tests.

Training Sessions

The Purpose of Contract Resistance Testing – 7 minutes
Describes the effect of resistance in circuit breaker and disconnect contacts. Describes common causes of contact resistance. Explains the purpose of contact resistance testing.

Test Equipment – 11 minutes
Describes the principle of contact resistance testing. Describes the components of a typical contact resistance test set.

Test Connections – 11 minutes
Describes the principle for connecting the current leads and voltage leads of a micro-ohmmeter to a resistance to be tested. Identifies the test connects for testing the contact resistance of a typical draw-out type circuit breaker. Identifies the test connections for testing the contact resistance of a typical high-voltage oil circuit breaker. Identifies the test connections for testing the contact resistance of a typical non-load-break disconnect switch.

Test Procedures and Results – 10 minutes
Describes common procedures and safety precautions for performing a contact resistance test. Explains the meanings of various test results.

Support Materials Available

Student workbook, instructor guide.