This unit involves the skills and knowledge required to solve problems in polyphase electronic power control circuits.

It includes preparing and solving problems in polyphase electronic power control circuits. It also includes testing and documenting solutions.

Typical polyphase electronic power control problems are those encountered in meeting performance requirements and industry compliance standards, revising control operating parameters and dealing with control malfunctions.

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) alternating current (a.c.) or 120 V direct current (d.c.).

Competency development activities in this unit are subject to regulations directly related to licensing. Where a licence or permit to practice is not held, a relevant contract of training, such as an Australian Apprenticeship, is required.

Additional and/or other conditions may apply in some jurisdictions subject to regulations related to electrical work. Practice in the workplace and during training is also subject to work health and safety (WHS)/occupational health and safety (OHS) regulations.

ELEMENTS

PERFORMANCE CRITERIA

Elements describe the essential outcomes.

Performance criteria describe the performance needed to demonstrate achievement of the element.

1

Identify problems in polyphase electronic power control circuits

1.1

WHS/OHS requirements and workplace procedures are identified and applied

1.2

Hazards are identified, risks are assessed and control measures implemented

1.3

Extent of polyphase electronic power control problems are determined from performance specifications, situation reports and consultations with relevant person/s

1.4

Work activities are planned to meet scheduled timelines in consultation with relevant person/s

1.5

Tools, equipment and testing devices needed for work are obtained in accordance with workplace procedures and checked for correct operation and safety

2

Solve problems in polyphase electronic power control circuits

2.1

WHS/OHS risk control measures and workplace procedures for carrying out the work are followed

2.2

Polyphase electronic power control devices, circuit operation characteristics and applications are applied to developing solutions to control problems

2.3

Parameters, specifications and performance requirements in relation to each polyphase electronic power control problem are obtained in accordance with workplace procedures

2.4

Solutions to polyphase electronic power control problems are evaluated to determine most effective resolution

2.5

Unplanned situations are responded to in accordance with workplace procedures in a manner that minimises risk to personnel and equipment

2.6

Problems are resolved using sustainable energy practices and principles without wasting materials, damaging apparatus, the surrounding environment or services in accordance with workplace procedures

3

Test and document solutions to polyphase electronic power control problems

3.1

WHS/OHS risk control measures and procedures for carrying out the work are followed

3.2

Solutions to polyphase electronic power control problems are tested to determine effectiveness and modified, as required

3.3

Solutions are documented, including instructions for implementation, incorporating risk control measures

3.4

Solutions used to solve polyphase electronic power control problems are justified and documented in accordance with workplace procedures

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions on at least two separate occasions and include:

applying relevant work health and safety (WHS)/occupational health and safety (OHS) requirements, including implementing risk control measures

applying sustainable energy principles and practices

dealing with unplanned events/situations in accordance with workplace procedures in a manner that minimises risk to personnel and equipment

determining the extent of the polyphase electronic power control problem

developing, evaluating and testing solutions to polyphase electronic power control problem

documenting justification of solutions implemented in accordance with workplace procedures

following scheduled timeframes

obtaining electronic device and circuit parameters, specifications and performance requirements appropriate to each problem

resolving problems in polyphase electronic power control circuits

testing and documenting solutions to polyphase electronic power control circuits.

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions and include knowledge of:

job safety assessments or risk mitigation processes, including risk control measures

three phase rectifier circuits, including:

three phase circuit configurations

resistive/inductive loads

output voltages/waveforms

ripple voltage/frequency

peak reverse voltages

freewheeling diodes

measurement of rectifier output parameters

three phase half wave-controlled rectifiers, including:

phase control

purpose/operation of half wave-controlled rectifiers

circuit configuration

rectifier performance and operation - resistive loads

output voltage resistive load

rectifier performance and operation - inductive loads

rectifier output waveforms

applications and limitations

advantages and disadvantages three phase half wave-controlled rectifiers

three phase half-controlled bridge rectifier, including:

purpose/operation of a half-controlled bridge rectifiers

circuit configuration and connections

rectifier output - resistive loads

output voltage resistive loads

rectifier output - inductive loads

output voltage - inductive loads

flywheel diode

output voltage calculations

applications and limitations

advantages and disadvantages three phase half-controlled bridge rectifiers

three phase fully controlled bridge rectifier, including:

purpose/operation of a fully controlled bridge rectifiers

circuit configuration and connections

rectifier output - resistive loads

output voltage resistive loads

rectifier output - inductive loads

output voltage - inductive loads

flywheel diode

output voltage calculations

applications and limitations

advantages and disadvantages three phase fully controlled bridge rectifiers

three phase alternating current (a.c.) controllers, including:

circuit configurations

circuit operation

triacs and silicon controlled rectifier (SCR) circuits

triggering requirements

output voltage and waveforms

determination of output voltage

applications

advantages and disadvantages

direct current (d.c.) converters, including:

purpose and operation of d.c. converters

circuit configurations

voltage control methods

forced commutation methods

calculation of load voltage

output voltage/waveforms

applications

advantages and disadvantages

cyclo-converters, including:

purpose/operation of a cyclo-converter

basic circuit configurations

measurement of output voltage

calculation of load voltage

output voltage/waveforms

applications and limitations

advantages and disadvantages

inverters, including:

purpose/operation of an inverter

basic circuit configurations

measurement of inverter outputs

output voltage

applications and limitations

advantages and disadvantages

thyristor protection, including:

power control devices failure

protection techniques

snubber networks

series inductors

amp trap high rupturing capacity (HRC) fuses

gate pulse suppression

installation of thyristor devices and circuits, including:

need for heat sinking of power thyristor devices

heat sink features and types

installation methods for all types of thyristor packages

basic thermal model, only to demonstrate the effect of different heat sink

types and profiles and installation methods on thyristor junction temperature

series and parallel thyristor connections, including:

purpose of series/parallel connection

series connections

reasons

operational problems

parallel connections

reasons

operational problems

fault finding three phase thyristor circuits, including:

fault finding procedures

typical faults power and trigger circuits

characteristics displayed by common faults

comparison of test data with expected data (voltage/current waveforms)

location and replacement of faulty components

problem-solving techniques

relevant manufacturer specifications

relevant tools, equipment and testing devices

relevant WHS/OHS legislated requirements

relevant workplace documentation

relevant workplace policies and procedures

sustainable energy principles and practices.

Assessors must hold credentials specified within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must satisfy the Principles of Assessment and Rules of Evidence and all regulatory requirements included within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must occur in workplace operational situations where it is appropriate to do so; where this is not appropriate, assessment must occur in simulated workplace operational situations that replicate workplace conditions.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

Resources for assessment must include access to:

a range of relevant exercises, case studies and/or other simulations

relevant and appropriate materials, tools, equipment and personal protective equipment (PPE) currently used in industry

applicable documentation, including workplace procedures, equipment specifications, regulations, codes of practice and operation manuals.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

Range is restricted to essential operating conditions and any other variables essential to the work environment.

Non-essential conditions may be found in the UEE Electrotechnology Training Package Companion Volume Implementation Guide.

Solving electrical problems in polyphase electronic power control circuits must include at least four of the following:

polyphase electronic power control circuits

Electrotechnology

Instrumentation & Control