Electrical Engineering XYZ MCQs
The armature shaft must be able to withstand:
- Any unbalanced magnetic pull on the armature core
- Bending moment due to weight of the armature
- Twisting stains due to transmission of torque
- All of these
Correct answer: 4. All of these
Explanation:
- Any unbalanced magnetic pull on the armature core: This refers to the force exerted on the armature due to any imbalance in the magnetic field. In an electric motor, the armature interacts with the magnetic field generated by the stator. If there’s any imbalance in this magnetic field, it can exert forces on the armature. Therefore, the armature shaft must be able to withstand such forces without failure.
- Bending moment due to weight of the armature: The weight of the armature exerts a downward force, creating a bending moment on the armature shaft. This bending moment can lead to structural stresses in the shaft. Hence, the shaft must be designed to withstand these bending stresses to prevent failure.
- Twisting strains due to transmission of torque: In an electric motor, torque is transmitted from the armature to the load. This transmission of torque creates twisting strains in the armature shaft. The shaft must be able to withstand these twisting strains without deforming or failing.
Therefore, the armature shaft must be able to withstand all of these forces and moments to ensure the proper functioning and longevity of the electric motor.