What controls generator output voltage?

What controls generator output voltage?

• A. By regulating the rotor speed.
• B. By using a fixed terminal voltage.
• C. By controlling the field current strength through the use of a voltage regulator.
• D. By changing the battery voltage.

Answer: (C)

The voltage a generator delivers is controlled by the excitation of the field winding. The field current determines the strength of the rotor’s magnetic field, which in turn sets the generated EMF and the terminal voltage. An automatic voltage regulator senses the terminal voltage and adjusts the field current to keep the output at the desired level as load changes. Increase field current and the voltage rises; decrease field current and the voltage falls. Speed mainly sets frequency, not voltage, so changing rotor speed won’t reliably control voltage. A fixed terminal voltage isn’t how regulation is achieved, and the battery’s voltage is part of the excitation path, not the primary method used to regulate the generator’s output voltage.

The voltage a generator delivers is controlled by the excitation of the field winding. The field current determines the strength of the rotor’s magnetic field, which in turn sets the generated EMF and the terminal voltage. An automatic voltage regulator senses the terminal voltage and adjusts the field current to keep the output at the desired level as load changes. Increase field current and the voltage rises; decrease field current and the voltage falls.

Speed mainly sets frequency, not voltage, so changing rotor speed won’t reliably control voltage. A fixed terminal voltage isn’t how regulation is achieved, and the battery’s voltage is part of the excitation path, not the primary method used to regulate the generator’s output voltage.