AMPP Cathodic Protection Technician CP2 Practice Exam 2025 – Complete Test Prep

The indicator that suggests the transformer is still functional is the presence of an audible hum from starting. This hum typically occurs due to the magnetic fields oscillating within the transformer when it is energized. It indicates that electric current is flowing through the windings and that the transformer is operational to some extent.

The other options do not adequately indicate functionality. For instance, constant resistance readings might suggest there is no short circuit or open circuit, but it does not confirm that the transformer is operational under load conditions. A lack of input to output translation indicates a more severe fault, where the transformer may not be performing its function of stepping voltage up or down. While presence of output voltage is a significant indicator of functionality, the audible hum at startup is more indicative that the transformer is in the initial phase of operation and is healthy enough to produce that output sound.