Electrical Engineering XYZ MCQs
In DC generators brushes are used for:
- Reduce eddy current loss
- Convert AC armature current into DC
- Collecting voltage
- Collecting current without any sparking
Correct answer: 4. Collecting current without any sparking
Explanation: Brushes in DC generators serve the purpose of maintaining electrical contact between the rotating armature (coil) and the stationary parts of the generator, such as the external circuit. They are typically made of carbon or graphite and are in direct contact with the commutator, which is a rotary switch that reverses the direction of the current in the coil windings as it rotates.
The main functions of brushes in DC generators include:
- Collecting Current: Brushes collect the current generated in the armature windings as it rotates within the magnetic field. This collected current is then transferred to the external circuit for use.
- Without Sparking: Brushes help in providing a smooth and continuous transfer of current without sparking. The commutator segments reverse the current direction at specific points in the rotation, and the brushes ensure that this reversal occurs without interruption and sparking.