# Module 3. Electrical fundamentals (Part-66)

## Module 3. Electrical fundamentals (Part-66)

### Duration

100 hours training

### Number of Participants

None.

### Price

None.

### Content

## Content: Part-66 Module 3. Electrical fundamentals

### 1. Electron Theory

- Structure and distribution of electrical charges within: atoms, molecules,ions, compounds;
- Molecular structure of conductors, semiconductors and insulators.

### 2. Static Electricity and Conduction

- Static electricity and distribution of electrostatic charges;
- Electrostatic laws of attraction and repulsion;
- Units of charge, Coulomb's Law;
- Conduction of electricity in solids, liquids, gases and a vacuum.

### 3. Electrical Terminology

- The following terms, their units and factors affecting them: potentialdifference, electromotive force, voltage, current, resistance, conductance,charge, conventional current flow, electron flow.

### 4. Generation of Electricity

- Production of electricity by the following methods: light, heat, friction,pressure, chemical action, magnetism and motion.

### 5. DC Sources of Electricity

- Construction and basic chemical action of: primary cells, secondary cells,lead acid cells, nickel cadmium cells, other alkaline cells;
- Cells connected in series and parallel;
- Internal resistance and its effect on a battery;
- Construction, materials and operation of thermocouples;
- Operation of photo-cells.

### 6. DC Circuits

- Ohms Law, Kirchoff's Voltage and Current Laws;
- Calculations using the above laws to find resistance, voltage and current;
- Significance of the internal resistance of a supply.

### 7. Resistance/Resistor

### 7.1 Resistance and affecting factors;

- Specific resistance;
- Resistor colour code, values and tolerances, preferred values, wattageratings;
- Resistors in series and parallel;
- Calculation of total resistance using series, parallel and seriesparallel combinations;
- Operation and use of potentiometers and rheostats;
- Operation of Wheatstone Bridge.

### 7.2 Positive and negative temperature coefficientconductance;

- Fixed resistors, stability, tolerance and limitations,methods of construction;
- Variable resistors, thermistors, voltage dependentresistors;
- Construction of potentiometers and rheostats;
- Construction of Wheatstone Bridge;

### 8. Power

- Power, work and energy (kinetic and potential);
- Dissipation of power by a resistor;Power formula;
- Calculations involving power, work and energy.

### 9. Capacitance / Capacitor

- Operation and function of a capacitor;
- Factors affecting capacitance area of plates, distance between plates,number of plates, dielectric and dielectric constant, working voltage,voltage rating;
- Capacitor types, construction and function;
- Capacitor colour coding;
- Calculations of capacitance and voltage in series and parallel circuits;
- Exponential charge and discharge of a capacitor, time constants;
- Testing of capacitors.

### 10. Magnetism

### 10.1 Theory of magnetism;

- Properties of a magnet;
- Action of a magnet suspended in the Earth's magnetic field;
- Magnetisation and demagnetisation;
- Magnetic shielding;
- Various types of magnetic material;
- Electromagnets construction and principles of operation;
- Hand clasp rules to determine: magnetic field around current carryingconductor.

### 10.2 Magnetomotive force, field strength, magnetic flux density, permeability,hysteresis loop, retentivity, coercive force reluctance, saturation point,eddy currents;

- Precautions for care and storage of magnets.

### 11. Inductance/Inductor

- Faraday's Law;
- Action of inducing a voltage in a conductor moving in a magnetic field;
- Induction principles;
- Effects of the following on the magnitude of an induced voltage: magneticfield strength, rate of change of flux, number of conductor turns;
- Mutual induction;
- The effect the rate of change of primary current and mutual inductancehas on induced voltage;
- Factors affecting mutual inductance: number of turns in coil, physical sizeof coil, permeability of coil, position of coils with respect to each other;
- Lenz's Law and polarity determining rules;
- Back emf, self induction;
- Saturation point;
- Principle uses of inductors;

### 12. DC Motor / Generator Theory

- Basic motor and generator theory;
- Construction and purpose of components in DC generator;
- Operation of, and factors affecting output and direction of current flow in DC generators;
- Operation of, and factors affecting output power, torque, speed anddirection of rotation of DC motors;
- Series wound, shunt wound and compound motors;S
- tarter Generator construction.

### 13. AC Theory

- Sinusoidal waveform: phase, period, frequency, cycle;
- Instantaneous, average, root mean square, peak, peak to peak currentvalues and calculations of these values, in relation to voltage, current andpower Triangular / Square waves;
- Single / 3 phase principles.

### 14. Resistive (R), Capacitive (C) and Inductive (L) Circuits

- Phase relationship of voltage and current in L, C and R circuits, parallel,series and series parallel;
- Power dissipation in L, C and R circuits;
- Impedance, phase angle, power factor and current calculations;
- True power, apparent power and reactive power calculations.

### 15. Transformers

- Transformer construction principles and operation;
- Transformer losses and methods for overcoming them;
- Transformer action under load and no-load conditions;
- Power transfer, efficiency, polarity markings;
- Calculation of line and phase voltages and currents;
- Calculation of power in a three phase system;
- Primary and Secondary current, voltage, turns ratio, power, efficiency;
- Auto transformers.

### 16. Filters

- Operation, application and uses of the following filters: low pass, highpass, band pass, band stop.

### 17. AC Generators

- Rotation of loop in a magnetic field and waveform produced;
- Operation and construction of revolving armature and revolving field type AC generators;
- Single phase, two phase and three phase alternators;
- Three phase star and delta connections advantages and uses;
- Permanent Magnet Generators.

### 18. AC Motors

- Construction, principles of operation and characteristics of: AC synchronous and induction motors both single and polyphase;
- Methods of speed control and direction of rotation;
- Methods of producing a rotating field: capacitor, inductor, shaded or splitpole.

### Objectives

None.

### Target Group

None.

### Aircraft Engine

None.

### Prerequisites

None.

### Examination

None.