Asked by dallasboy
How does an electric generator work?
The axle rotates the armature in the magnetic field of a permanent magnet, which induces an electric current.
The armature rotates the axle in the magnetic field of a permanent magnet, which induces an electric current.
The axle rotates the armature in the magnetic field of an electromagnet, which induces an electric current.
The armature rotates the axle in the magnetic field of an electromagnet, which induces an electric current.
All Answers 1
Answered by
GPT-5 mini
AI
The correct options are 1 and 3.
Why: a generator works by electromagnetic induction — a conductor (the armature, usually coils of wire) moving relative to a magnetic field has a changing magnetic flux through it, which induces an emf (Faraday’s law). In the usual description the axle (shaft) is driven by some mechanical source and rotates the armature in the magnetic field. That magnetic field can be provided either by permanent magnets (option 1) or by electromagnets/field coils (option 3).
Notes and nuance:
- What matters is relative motion between the magnetic field and the conductors; some machines instead rotate the field (the magnets or field coils) while the armature is stationary (common in large alternators).
- AC generators use slip rings to make a rotating emf available as alternating current; DC generators use a commutator to rectify the generated emf to DC.
- Quantitatively: induced emf ≈ −N dΦ/dt (Faraday’s law), where Φ is magnetic flux and N the number of turns.
Why: a generator works by electromagnetic induction — a conductor (the armature, usually coils of wire) moving relative to a magnetic field has a changing magnetic flux through it, which induces an emf (Faraday’s law). In the usual description the axle (shaft) is driven by some mechanical source and rotates the armature in the magnetic field. That magnetic field can be provided either by permanent magnets (option 1) or by electromagnets/field coils (option 3).
Notes and nuance:
- What matters is relative motion between the magnetic field and the conductors; some machines instead rotate the field (the magnets or field coils) while the armature is stationary (common in large alternators).
- AC generators use slip rings to make a rotating emf available as alternating current; DC generators use a commutator to rectify the generated emf to DC.
- Quantitatively: induced emf ≈ −N dΦ/dt (Faraday’s law), where Φ is magnetic flux and N the number of turns.
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