We know that various types of DC Generators are used to perform one core action that is to convert mechanical energy into direct current. This works on the principle of induced emf produced dynamically. A magnetic flux is produced while passing a circulating current in the field windings, which is called excitation. These are classified according to the methods of field excitation.
Classification of DC Generators on the method of excitation:
- Permanent Magnet
- Separately Excited
- Self Excited
- Shunt Wound
- Series Wound
- Compound Wound
Permanent Magnet Type DC Generator
Here, no field windings are present near the poles. The poles produce constant fields here. This is very small and used in dynamos in cycles etc. The magnets produce flux which gets deteriorated with the passage of time and indeed changes the characteristics of the machine.
Separately Excited DC Generator
Here, the field windings are energized by a separate DC source. The flux generated on the poles depends upon field current, and the saturated region remains constant.
Self Excited DC Generator
The generator provides the current to the field winding. When the electric generator is off, a small is developed in the rotor which induces an electromotive force in the armature and producing current in the field windings.
The self-excited DC generator is further classified into:
Shunt Wound Generator
Here, the field winding is connected across the armature windings in a parallel also known as shunt circuit, which helps to apply a full terminal voltage across it.
Series Wound Generator
Here, the field coils are connected in series with the armature windings. The armature current is carried in the series field windings.
These were some types of DC Generators. If you wish to know more, download BYJU’S The Learning App