Which device sends a representative voltage to the control box from the regulator output?

• A. Potential transformer
• B. Current transformer
• C. Control panel
• D. Line drop compensator

Answer: (A)

To provide the control box with a safe, proportional signal of the regulator output, you use a device that scales down high voltage to a low, representative voltage. A potential transformer does exactly that by stepping down the regulator’s high voltage to a manageable level for the control circuitry, while preserving the proportional relationship.

A current transformer would produce a signal proportional to current, not voltage, so it wouldn’t feed the control box with the appropriate voltage representation. A line drop compensator is involved in adjusting voltage under load along the line, not in sensing and feeding the control box. The control panel is the interface, not the sensing element. Therefore, the device that sends a representative voltage to the control box from the regulator output is the potential transformer.