Series Generator Voltage Behaviour

A series generator is a type of DC generator where the field winding is connected in series with the armature and the load.

• The magnetic field strength is directly proportional to the load current because the field winding carries the same current as the load.
• Consequently, the generated EMF and the terminal voltage of a series generator vary significantly with changes in the load current.
• Specifically, the terminal voltage is heavily dependent on the load. As load current increases, terminal voltage increases (up to a point); as load current decreases, terminal voltage decreases rapidly.

Series Generator Usage Limitations

The primary reason series generators are generally not used for general power supply applications is the unstable nature of their terminal voltage.

• Applications like lighting or power distribution require a relatively constant voltage supply regardless of load fluctuations.
• The high variability of the terminal voltage in series generators makes them unsuitable for such purposes.
• While they have specific niche uses (e.g., as voltage boosters or in arc lighting historically), their inherent voltage instability prevents widespread use as main generators.
• Therefore, the terminal voltage varying with load variation is the key drawback.