Elements describe the essential outcomes. | Performance criteria describe the performance needed to demonstrate achievement of the element. |
1 | Explain how material properties affect resistance of electrical conductors | 1.1 | Terms and symbols used in the formula for resistivity are used correctly |
1.2 | How resistance varies with changes in conductor length and cross sectional area is outlined |
1.3 | How resistance varies with temperature is outlined |
1.4 | Calculations are performed that illustrate how material properties affect resistance of electrical conductors |
2 | Apply Ohm’s Law to electrical circuits | 2.1 | Main sources of EMF are identified |
2.2 | Terms and symbols used in Ohm’s Law are used correctly |
2.3 | Calculations are performed using Ohm’s Law to solve problems involving internal, external and variable resistances in both series and parallel circuits |
2.4 | Calculations are performed to determine power required and /or energy expended by electrical devices |
2.5 | Circuits for a wheatstone bridge and a slide wire bridge are sketched and their application on a ship is outlined |
2.6 | Calculations are performed dealing with resistances, currents and voltage drops in bridge circuits under null or balanced conditions |
3 | Apply principles of electrolytic action to electrical cells | 3.1 | How the theory of electrolytic disassociation when applied to common electrolytic solutions and electrode materials explains the generation of EMF from chemical sources, is outlined |
3.2 | Primary cells are distinguished from secondary cells |
3.3 | Calculations are performed to solve problems involving currents, voltage drops and terminal potential difference of cells connected to form batteries in series and in parallel |
3.4 | How capacity of a battery is measured is explained |
3.5 | Construction of typical batteries used in marine environments is outlined |
4 | Apply principles of electromagnetism to EMF generation | 4.1 | Form and properties of the magnetic fields surrounding single conductor and multi-turn solenoid coils when carrying an electrical current are compared and contrasted |
4.2 | Terms and symbols used in Faraday’s and Lenz’s laws of electromagnetic induction are used correctly |
4.3 | Calculations are performed using Faraday’s and Lenz’s laws of electromagnetic induction to solve problems related to electromagnetism and EMF generation |
4.4 | Fleming’s Right Hand Rule is outlined |
5 | Explain operation of direct current rotating machinery | 5.1 | Construction and methods of maintaining and repairing typical direct current (DC) machines are illustrated |
5.2 | Principle wiring arrangements used with DC machines are outlined |
5.3 | Action of the commutator in DC generators is outlined |
5.4 | Significance of Back EMF (Eb) in the operation of DC motors is outlined |
5.5 | Mathematical formula are applied to show relationships between operational parameters of DC motors |
5.6 | Calculations are performed to solve simple problems relating to power output and efficiency in DC motors |
6 | Explain operation of AC rotating machinery | 6.1 | How three-phase AC may be developed out of simple single phase AC is explained |
6.2 | Difference between Star and Delta connections is outlined |
6.3 | How a three-phase supply can generate a rotating magnetic field is explained |
6.4 | Construction of an AC synchronous generator is outlined |
6.5 | Construction of an AC induction motor is outlined |
6.6 | Calculations are performed to show how driving torque is produced in an induction motor |
7 | Explain parallel operation and load sharing of generator | 7.1 | Load/voltage curves of AC and DC generators are compared |
7.2 | Main requirements for satisfactory power sharing between both AC and DC generators are outlined |
7.3 | Sequences that occur when load changes on two DC generators working in parallel without an equaliser connection are outlined |
7.4 | Effect of varying power factors on the load/voltage curve of an AC generator is outlined |