This unit involves the skills and knowledge required to ascertain correct operation of single and three phase alternating current (a.c.) circuits and solving circuit problems as they apply to servicing, fault finding, installation and compliance work functions.
It includes safe working practices, multi-phase circuit arrangements, issues related to fault protection, power factor and multiple earthed neutral (MEN) systems and solutions to circuit problems derived from calculated and measured parameters.
The skills and knowledge described in this unit require a licence or permit to practice in the workplace where work is carried out on electrical installations which are designed to operate at voltages greater than 50 volt (V) a.c. or 120 V direct current (d.c.).
Assessment tasks will be designed to reinforce & extend knowledge and skill competence within set & controlled parameters in accordance with each unit’s learning outcomes & performance criteria requirements, incl the setting of work based practical application tasks designed to provide evidence of competence outcomes, within periodic and scheduled timelines.
Students will be expected to demonstrate the following required skills:
*applying relevant work health and safety (WHS)/occupational health and safety (OHS) requirements Including:
*implementing OHS/WHS workplace procedures and practices, including risk control measures
*safely measuring the parameters for the whole or any part of a circuit
*measuring instantaneous, peak, peak-to-peak values and the period of a sinusoidal waveform
*the phase angle between two or more alternating quantities from a given sinusoidal waveform diagram
*the fault-loop impedance of typical circuits
*the branch currents and voltages in a series and parallel resistance inductance capacitance (RLC) circuit and use a phasor diagram to determine the total current and phase angle between circuit voltage and circuit current
*determining phase relationship between two or more sinusoidal waveforms from a given diagram
*the impedance, current and voltages and phase angles for a series and parallel resistance capacitance (RC), resistance inductance (RL), and RLC circuit given the resistance, capacitance, inductance and supply voltage
*comparison of current limiting characteristics of inductors and resistors
*the relationship between inductive reactance and capacitive reactance and frequency
*difference between true power, apparent power and reactive power and the units in which these quantities are measured
*the root-mean-square (rms) value of line and phase, voltage and current given any one of these quantities
*the effects of a high impedance in the neutral conductor of a three phase four wire system supplying an unbalanced load where multiple earthed neutral (MEN) earthing is employed
*the value of neutral current in an unbalanced three phase four wire systems given line currents and power factors
*how the power factor of a three phase installation can be improved
*fault loop impedance using resistance and reactance values from relevant industry standards
*voltage, current and resistance from measured or given values of any two of these qualities
*the phase sequence of a three phase supply
*drawing and labelling the following:
*the power triangle to show the relationships between true power, apparent power and reactive power
*the typical combinations of three phase interconnected systems using star and delta connection
*the impedance triangle for a series RC, RL and RLC circuit
*the equivalent circuit of a practical inductor
*phasor diagrams to show:
*the relationship between two or more alternating current (a.c.) values of voltage and/or current, including 'in-phase', 'out-of-phase', 'phase angle', lead' and 'lag'
*a series and parallel RC, RL, and RLC circuits
*calculating:
*rms value of voltage generated in each phase given the maximum value
*terms in relation to a sinusoidal waveform from values of root-mean-square (rms) value, frequency, peak voltage, period and instantaneous value
*capacitive reactance and inductive reactance for a given capacitor and inductor
*total impedance for a series and parallel RLC circuit
*connecting a three-phase star and delta load
*setting up and connecting a single-source resistive a.c. circuit and taking voltage and current measurements to determine the resistance
*applying sustainable energy principles and practices
*completing workplace documentation
*voltage, current and reactance of inductive and capacitive reactance by applying Ohm's law in purely inductive and capacitive a.c. circuits given any two quantities
*altering an existing circuit to comply with specified operating parameters
*developing circuits to comply with a specified function and operating parameters
*determining conditions causing an existing circuit to be unsafe
*dealing with unplanned events.
The qualified trainer and assessor will provide teaching and learning materials as required in the form of workbooks produced by Victoria University and/or via the Victoria University e-learning system.
This unit is studied as part of the following course(s):