A ______ is installed on the output of the regulator. It sends a representative voltage to the control box.

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

Answer: (B)

The device used is a potential transformer. In high-voltage regulator applications, you need to feed the control box a safe, scaled version of the actual output voltage so the control system can monitor and regulate without exposing components to full line voltage. A potential transformer steps the high output voltage down to a lower, proportional voltage that the control box can read accurately. This proportional representation allows the regulator to respond correctly to changes in output. A current transformer would deliver a current signal rather than a voltage signal, which isn’t what the control box needs for voltage feedback. A line drop compensator adjusts for voltage drop along the line, not for providing a sensing voltage to the control box.