During a pre-op inspection of a MEP 12, the voltage regulator switch should be in what position?

The voltage regulator switch should be set to the auto position during a pre-operational inspection of a Medium Electric Power (MEP) 12 generator. When the switch is in auto, the voltage regulator is actively managing the generator's output voltage, ensuring it remains within the required limits for safe and efficient operation. This automatic adjustment is essential for maintaining stability in the electrical system and preventing damage to connected equipment.

In the auto position, the voltage regulator can respond quickly to fluctuations in load, effectively managing the system's voltage output without manual intervention. This is crucial during the pre-op phase, as it prepares the generator for any upcoming load demands and ensures it is functioning correctly before actual operation begins.

The other positions, such as off, manual, and bypass, do not provide the necessary automatic control needed during pre-operation. Off would disable the regulator entirely, manual would require constant monitoring and adjustment by a technician, and bypass may negate the regulator's functionality, which could lead to voltage instability.