Electrical Engineering XYZ MCQs
The armature of DC motor is laminated:
- To reduce the eddy current loss
- To reduce the hysteresis loss
- To reduce the mass
- To reduce the inductor
Correct answer: 1. To reduce the eddy current loss
Explanation: In electrical machines such as DC motors, the armature is subjected to a changing magnetic field as it rotates in the magnetic field of the stator. Laminating the armature core, which involves making it from thin layers of electrical steel separated by insulating material, helps to reduce the eddy currents that are induced by the changing magnetic field. Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor, according to Faraday’s law of electromagnetic induction. These currents within the iron of the armature can cause significant power losses and heating. By laminating the core, the cross-sectional area through which these currents can flow is reduced, thereby minimizing these undesirable losses.