What action must be taken with the black demand pointer of a kilowatt-hour meter?

The black demand pointer of a kilowatt-hour meter serves a crucial function in measuring and recording the maximum demand of electrical usage over a specific time period. When you select the correct option, which states that the black demand pointer must be manually reset, it highlights the operational aspect of the demand meter. After measuring the peak demand during a given interval, the black demand pointer retains this maximum value until it is specifically reset by the operator.

This reset action is vital for ensuring that subsequent measurements can accurately reflect the new demand levels, rather than retaining previous values, which could lead to misleading interpretations of electrical usage and efficiency. Proper management of the demand pointer is essential in applications where monitoring power consumption closely is important for both operational efficiency and cost management.

The other options do not accurately reflect the function of the black demand pointer. For example, while the demand pointer plays a role in analyzing electrical consumption, it does not directly move the red pointer or indicate maximum voltage, nor does it read the current demand. Understanding the necessity of manually resetting this pointer helps in precise energy management in refrigeration and other electrical systems.