Generator Principles and AC vs DC

Flashcards covering the mechanical positions of a generator coil, methods for increasing induced emf, and the advantages of alternating current over direct current.

Coil position at $180^\circ$

A horizontal position where the plane of the coil is parallel to the magnetic field lines, resulting in the greatest rate of change in magnetic flux and maximum induced emf and current.

Coil position at $270^\circ$

A vertical position where the plane of the coil is perpendicular to the magnetic field lines, resulting in zero change in magnetic flux and zero induced emf and current.

Coil position at $360^\circ$

A horizontal position where the plane of the coil is parallel to the magnetic field lines, resulting in the maximum number of magnetic field lines being cut and maximum induced current.

Uses of DC generators

Common applications including bicycle dynamos for lights, winding or shaking torches, and battery chargers.

Increasing generator output (Coil)

Increase the surface area of the loop by increasing the number of turns or windings on the coil.

Increasing generator output (Armature)

Increase the speed at which the coil or armature is rotated.

Increasing generator output (Magnets)

Use stronger magnets (such as electromagnets) or curved magnets to increase the strength of the magnetic field.

Iron core

A component used in a generator to help increase the output, induced emf, and induced current.

Voltage Stepping

The advantage of AC where a transformer is used to easily step voltage up or down.

AC Transmission Efficiency

AC voltages can be stepped up to transmit power over long distances at low current, minimizing power loss due to heating.

AC to DC Conversion

A process that is easier and cheaper to perform than converting direct current to alternating current.