Electrical Engineering XYZ MCQs
Generators work on the principle of production of:
- Statically induced EMF
- Dynamically and statically induced EMF
- Dynamically induced EMF
- None of the above
Correct answer: 3. Dynamically induced EMF
Explanation:
Generators convert mechanical energy into electrical energy based on the principle of electromagnetic induction. The fundamental principle behind their operation is Faraday’s Law of Electromagnetic Induction, which states that a voltage (or electromotive force – emf) is induced in a conductor when it is exposed to a changing magnetic field.
There are two types of electromagnetic induction:
- Static Induction – This occurs when a conductor is stationary, and the magnetic field around it changes. Static induction typically occurs in transformers.
- Dynamic Induction – This occurs when a conductor moves through a magnetic field, or a magnetic field moves around a stationary conductor, creating a change in magnetic flux due to the relative motion between the magnetic field and the conductor. This is the principle that underlies the operation of generators.
In the context of generators:
- When a coil or a set of conductors (such as those in the armature of a generator) rotates within a magnetic field, the magnetic flux linkage through the coil changes. This change in flux linkage over time induces a voltage across the ends of the coil, which is a case of dynamically induced emf. This is because the induction is due to the motion of the conductor (or the rotational movement of the coil) relative to the magnetic field.
Therefore, generators primarily operate based on dynamically induced emf. Static induction does not typically play a role in the basic operation of most generators.