Voltage fluctuations are sensed by this in the carbon pile regulator.

Voltage fluctuations are sensed by this in the carbon pile regulator.

• A. Magnetic pick-up
• B. Current coil
• C. Voltage coil
• D. Voltage transformer

Answer: (C)

Voltage fluctuations are monitored directly by the voltage sensing element in the carbon pile regulator. This device, the voltage coil, is connected to the generator’s output and follows the actual line voltage. When the sensed voltage rises above the set point, the regulator adjusts the carbon pile path (or related control circuitry) to reduce the generator’s output; when the sensed voltage drops, it allows more output. This direct voltage sensing keeps the regulator responsive to the real system voltage, which is the essential idea behind maintaining a stable terminal voltage. The other options don’t fit because a magnetic pick-up measures rotor speed, not voltage; a current coil responds to output current rather than voltage; and a voltage transformer isn’t used here to sense voltage in the carbon pile regulator’s control loop.

Voltage fluctuations are monitored directly by the voltage sensing element in the carbon pile regulator. This device, the voltage coil, is connected to the generator’s output and follows the actual line voltage. When the sensed voltage rises above the set point, the regulator adjusts the carbon pile path (or related control circuitry) to reduce the generator’s output; when the sensed voltage drops, it allows more output. This direct voltage sensing keeps the regulator responsive to the real system voltage, which is the essential idea behind maintaining a stable terminal voltage.

The other options don’t fit because a magnetic pick-up measures rotor speed, not voltage; a current coil responds to output current rather than voltage; and a voltage transformer isn’t used here to sense voltage in the carbon pile regulator’s control loop.