Testing required to demonstrate reliability of emergency and standby power equipment

The author presents the development of a generalized sequential test plan for demonstrating whether an emergency and standby power system complies with the specifications dictated by the customer and manufacturer. The number of observed system failures versus the number of tests required for compliance evaluation is shown graphically. Acceptance and rejection lines are placed on the Cartesian coordinate system to define three distinct zones, namely, reject, continue testing, and acceptance. These regions are defined completely by four parameters that are necessary to define the sequential tests parameters. The acceptance and rejection line equations are expressed in a general form, which allows the risks to the manufacturer and the customer to be unique