Chapter 13/18 : AC Theory .
Chapter 14/18 : Resistive R, Capacitive C and Inductive L Ciruits .
Chapter 15/18 : Transformers.
Chapter 16/18 : Filters .

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

TRANSFORMERS
A transformer changes electrical energy of a given voltage into electrical energy at a different voltage level. It consists of two coils that are not electrically connected, but are arranged so that the magnetic field surrounding one coil cuts through the other coil. When an alternating voltage is applied to (across) one coil, the varying magnetic field set up around that coil creates an alternating voltage in the other coil by mutual induction. A transformer can also be used with pulsating DC, but a pure DC voltage cannot be used, since only a varying voltage creates the varying magnetic field that is the basis of the mutual induction process easa part 66 module 3 ebook.
A transformer consists of three basic parts. (Figure 15-1) These are an iron core which provides a circuit of low reluctance for magnetic lines of force, a primary winding which receives the electrical energy from the source of applied voltage, and a secondary winding which receives electrical energy by induction from the primary coil easa part 66 module 3 ebook.
The primary and secondary of this dosed core transformer are wound on a dosed core to obtain maximum inductive effect between the two coils. There are two classes easa part 66 module 3 ebook

Chapter 15/18 : Transformers.
Chapter 16/18 : Filters.
Chapter 17/18 : AC Generators .
Chapter 18/18 : AC Motors .

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

ALTERNATORS
ALTERNATORS & CLASSIFICATIONS An electrical generator is a machine, which converts mechanical energy into electrical energy by electromagnetic induction. A generator which produces alternating current is referred to as an AC generator and, through combination of the words “alternating” and “generator,” the word “alternator” has come into widespread use easa module 3 electricity.

In some areas, the word “alternator” is applied only to small AC generators. This text treats the two terms synonymously and uses the term “alternator” to distinguish between AC and DC generators. The major difference between an alternator and a DC generator is the method of connection to the external circuit; that is, the alternator is connected to the external circuit by slip rings, but the DC generator is connected by a commutator easa module 3 electricity.
METHOD OF EXCITATION One means of classification is by the type of excitation system used. In alternators used on aircraft, excitation can be affected by one of the following methods: 1. A direct connected, direct current generator. This system consists of a DC generator fixed on the easa module 3 electricity

Chapter 15/18 : Transformers.
Chapter 16/18 : Filters.
Chapter 17/18 : AC Generators .
Chapter 18/18 : AC Motors .

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

Sample          –  Electrical Exams ( 40 questions 30 min),
Category A   –  Electrical Exams ( 20 questions 25 min),
Category B1 –  Electrical Exams ( 52 questions 65 min),
Category B2 – Electrical Exams ( 52 questions 65 min),
Category B3 – Electrical Exams ( 24 questions 30 min),

AC MOTORS
Because of their advantages, many types of aircraft motors are designed to operate on alternating current. In general, AC motors are less expensive than comparable DC motors. In many instances, AC motors do not use brushes and commutators so sparking at the brushes is avoided. AC motors are reliable and require little maintenance. They are also well suited for constant speed applications and certain types are manufactured that have, within limits, variable speed part 66 module 3 electricity characteristics. Alternating current motors are designed to operate on polyphase or single phase lines and at several voltage ratings.
The speed of rotation of an AC motor depends upon the number of poles and the frequency of the electrical source of power:
120 x Frequency rpm – Number of Poles part 66 module 3 electricity Since airplane electrical systems typically operate at 400 cycles, an electric motor at this frequency operates at about seven times the speed of a 60 cycle commercial motor with the same number of poles. Because of this high speed of rotation, 400-cycle AC motors are suitable for operating small high-speed rotors, through reduction gears, in lifting and moving heavy loads, such as the wing flaps, the retractable landing gear, and the starting of engines. The 400-cycle induction type motor operates at speeds ranging from 6 000 rpm to 24 000 rpm. Alternating current motors are rated in horsepower output, operating voltage, full load current, speed, number of phases, and frequency. Whether the motors operate continuously or intermittently (for short intervals) is also considered in the rating part 66 module 3 electricity.