Module 3: Electrical Fundamentals II - AC Generators

The order in which the voltage reaches its peak value in a three-phase system. It can be ABC or ACB, depending on the direction of the rotor.

The frequency of an alternator is determined by the speed of the rotor and the number of poles. The formula to calculate frequency is (Speed x Number of poles) / 120.

A system that maintains a constant output frequency from an alternator, even when the engine speed varies. It uses a hydraulic pump and motor to control the generator's speed.

A system that combines a constant speed drive and an AC generator in a single unit. It provides reliable and constant frequency output.

A generator that converts mechanical energy into alternating current (AC) electricity.

The process of changing the magnetic field around a conductor to produce an electromotive force (EMF) and induce current flow.

A type of AC generator where the armature rotates within a stationary magnetic field.

A type of AC generator where the magnetic field rotates around a stationary armature.

An AC generator that produces a single alternating current waveform.

An AC generator that produces two alternating current waveforms that are 90 degrees out of phase.

An AC generator that produces three alternating current waveforms that are 120 degrees out of phase.

An AC generator that uses permanent magnets to create the magnetic field.

The process of inducing an electromotive force (EMF) in a coil by relative motion between the coil and a magnetic field.

A component of a generator that creates the magnetic field.

The part of a generator where voltage is induced.

A type of generator where the armature rotates and the field remains stationary.

A generator that produces alternating current (AC).

A type of alternator where the armature rotates and the field is stationary.

A type of alternator where the field rotates and the armature is stationary.

A part of a generator that allows current to flow from the rotor to the stator.

Alternators commonly found in aircraft, featuring a rotating field generated by permanent magnets.

A type of alternator utilizing permanent magnets to create a magnetic field, eliminating the need for brushes or slip rings.

Permanent Magnet Generators are often used in aircraft to power essential systems such as engine control and ignition.

The output power of a Permanent Magnet Generator is directly proportional to the speed at which the generator rotates.

An alternator designed without brushes or slip rings, making it highly efficient and reducing maintenance.

A brushless alternator uses three separate fields: a permanent magnetic field, an exciter field, and a main output field. These fields interact to produce electricity.

The permanent magnets in a brushless alternator first create a flux, which then induces voltage in the exciter field winding. This voltage in turn induces current in the main output field winding, producing the alternator's output.

In a brushless alternator, the exciter field output is rectified and sent to the generator control unit (GCU). The GCU then rectifies the AC output and sends it to the main output field winding.

The process where a loop rotates within a magnetic field, creating a changing magnetic flux and inducing an alternating current (AC) in the loop. The induced current's waveform is sinusoidal, oscillating between positive and negative values.

A type of AC generator where the armature (the part containing the coils) rotates, producing an AC current in the stationary field windings. Think of it as a spinning coil generating electricity in stationary coils.

A type of AC generator where the magnetic field rotates, inducing current in stationary armature windings. Think of it as a spinning magnet generating electricity in still coils.

In AC generators, different phase systems refer to the timing of the AC voltage in multiple output circuits. A three-phase generator has three circuits producing AC voltages that are offset by 120 degrees, meaning they reach peak values at different times.

Three-phase AC generator systems are designed for high-power applications and offer advantages like increased efficiency and reduced losses compared to single-phase systems. They use different connection schemes (star or delta) based on the application.

A rotating assembly within a brushless alternator. The assembly includes a permanent magnet, an exciter winding, an exciter rectifier, and the output field winding.

Located on the stator of a brushless alternator, these are windings designed to generate three-phase output power. They are connected in a 'Y' configuration, also known as a 'star' configuration.

The Generator Control Unit (GCU) monitors and regulates the main generator's output, controlling the amount of current that flows into the exciter field.

A type of winding in the brushless alternator that generates a variable magnetic field, which in turn induces voltage in the main output coils.

A waveform that varies equally around a fixed level, representing voltage or current. It is characterized by its symmetrical shape and alternating nature.

A type of electric current where the electrons flow in one direction and then the opposite direction. It has both voltage and current that change continuously.

The speed at which the magnetic flux is cut by the rotating coil affects the induced EMF. The faster the rate of cutting, the higher the EMF.