Which of the following is NOT a basic control found in a distribution step regulator control panel?

In a distribution step regulator control panel, the primary controls are designed to manage and regulate the voltage levels in the electrical distribution system. The basic controls typically include:

• Voltage Level: This allows the operator to set and monitor the desired voltage level for the system.

• Time Delay: This feature enables a delay before the regulator responds to changes in voltage, helping to prevent rapid cycling and improving the stability of the system.

• Selector Switch: This control is used to manually select different operating modes or configurations of the regulator.

The transformer rating, while an important specification for determining the capacity and limitations of the transformer itself, is not considered a basic operational control found on the control panel. Instead, it's more of a technical parameter that influences the overall system design but does not directly interact with the control mechanisms of the regulator. Thus, it is correct to identify transformer rating as the element that does not belong among the basic controls in a distribution step regulator control panel.