What do the labels on a subtractive transformer represent on secondary bushings?

The labels on the secondary bushings of a subtractive transformer typically represent the phase connections utilized in the operation of the transformer. In a subtractive transformer, the labels are used to indicate the respective outputs and their corresponding winding configurations.

The correct arrangement, labeled as x1, x3, x2, and x4, signifies specific phasing and winding connections that are critical for the correct performance and functionality of the transformer. These labels help linemen and technicians understand which connections need to be made based on the phase rotation and load requirements. Correct identification of these labels ensures that the transformer operates safely and efficiently within the power distribution system.

Other arrangements presented do not adhere to this specific labeling convention and could potentially lead to confusion in installation or maintenance, resulting in improper connections within the electrical system. Thus, the correct choice reflects the standard convention used in the industry for identifying transformer secondary bushings in a subtractive configuration.