Which statement best describes compounding?

• A. It uses both the series and shunt fields to regulate voltage with load changes.
• B. It uses only the shunt field to regulate current.
• C. It removes the series field from the circuit.
• D. It changes the armature speed by mechanical means.

Answer: (D)

Compounding means combining the shunt field with a series field so the total magnetic field changes as load changes. The shunt field alone sets a baseline voltage, but when you add a series field in series with the armature, that series field carries the load current and its flux adds to the shunt flux. As the outage current increases, the series field strengthens the overall field, which helps maintain the generated EMF and stabilizes the terminal voltage despite changes in load. This arrangement lets the generator respond to varying load more effectively, keeping voltage from dropping as you draw more current.

So the idea is that both the series and shunt fields work together to regulate voltage when the load changes. It’s not about regulating current with only the shunt field, not about removing the series field, and not about changing speed through mechanics—those describe different concepts (field arrangement for voltage regulation vs. mechanical speed control).