Page 1 of 5
Title / Demonstrate knowledge of a.c. electric motor control and installation
Level / 4 / Credits / 8
Purpose / This unit standard covers the starting, speed control, and installation and commissioning of alternating current (a.c.) electric motors. It is intended for use in the training of electricians and related trades.
People credited with this unit standard are able to:
–demonstrate knowledge of motor starters;
–demonstrate knowledge of motor speed controllers;
–connect and test three-phase induction motor starters;
–connect and test motor speed controllers; and
–install and commission induction motors.
Classification / Electrical Engineering > Electrical Installation and Maintenance
Available grade / Achieved
Explanatory notes
1This unit standard has been developed for learning and assessment off-job.
2Achievement of this unit standard does not by itself imply that trainees may legally perform prescribed electrical work in their own right. Until they are registered and licensed under the Electricity Act 1992, trainees are assisting, and must work under the supervision of a Supervisor of Electrical Work when carrying out prescribed electrical work. If the prescribed electrical work in question is carried out for reward the Supervisor of Electrical Work must hold a valid practising licence.
3References
Electricity (Safety) Regulations 2010;
Health and Safety in Employment Act 1992;
AS/NZS 3000:2007, Electrical installations (known as the Australian/New Zealand Wiring Rules), including Amendment 1;
AS/NZS 3760:2010, In-service safety inspection and testing of electrical equipment, including Amendment 1;
and all subsequent amendments and replacements.
4Definitions
The term current regulations and standards is used in this unit standard to refer to the requirements of the above.
The term safe and sound practice relating to the installation of electrical equipment is defined in AS/NZS 3000:2007.
5Demonstration of safe working practices, and installation in accordance with safe and sound practice are essential components of assessment for this unit standard.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of motor starters.
Evidence requirements
1.1The advantages of using motor starters are explained.
Rangereduced voltage and current during starting, reduced transients.
1.2Protective features incorporated in starters for common faults are described.
Rangeover current, no-volt, phase reversal, phase failure, mechanical stress.
1.3Motor starters are described with the aid of diagrams, with reference to principles of operation.
Rangeblock diagram of electronic starter;
circuit diagrams of – direct-on-line, star-delta, auto-transformer, primary resistance, secondary resistance.
1.4Characteristics of motor starters are compared.
Rangemotor starters – direct-on-line, star-delta, auto-transformer, primary resistance, secondary resistance, electronic;
characteristics – starting current and torque, full load current and torque, relative cost.
Outcome 2
Demonstrate knowledge of motor speed controllers.
Evidence requirements
2.1Operational requirements of motor speed controllers are described.
Rangestep-less or continuous control, minimum losses, minimum harmonic and radio-frequency interference.
2.2Properties of motors suitable for speed control are stated.
Rangedesigned for varying speeds, adequate cooling system.
2.3Motor speed controllers are described with the aid of diagrams.
Rangeblock diagrams – block diagram for variable voltage and variable frequency electronic speed controllers, circuit diagram for secondary resistance speed controller.
2.4Characteristics of motor speed controllers are compared.
Rangespeed controllers – secondary resistance, pole changing, electronic;
characteristics – efficiency, smoothness, torque, continuous control, relative cost.
Outcome 3
Connect and test three-phase induction motor starters.
Rangedirect on line (DOL) starting – cage induction motors with two and three-wire control and remote start-stop stations;
plus two of – auto transformer, star-delta, secondary resistance, DOL forward and reversing.
Evidence requirements
3.1Connections are made in accordance with safe and sound practice.
3.2Circuits are tested in accordance with current regulations and standards.
3.3Starting and stopping operations are verified against design.
3.4Motor protection is tested for effectiveness and calibrated to suit the motor.
Rangeover-current, overload, phase failure.
Outcome 4
Connect and test motor speed controllers.
Rangespeed controllers – secondary resistance and electronic types;
motors – universal single-phase, plus either three-phase cage induction, or three-phase slip ring induction.
Evidence requirements
4.1Connections are made in accordance with safe and sound practice.
4.2Motor is tested in accordance with current regulations and standards.
4.3Operation of speed controller is verified against design.
Outcome 5
Install and commission induction motors.
Rangeone single-phase and one three-phase induction motor.
Evidence requirements
5.1Electrical connections are made to the machine, including cabling, glands, terminations, and accessories, in accordance with specifications, and current regulations and standards.
5.2Control and protection equipment is installed in accordance with specifications, and current regulations and standards.
5.3Testing confirms that all requirements of current regulations and standards have been met, and that the machine and control equipment are safe to connect.
5.4Commissioning includes tests, adjustments, and confirmation of operation of control equipment in accordance with specifications.
Rangecontrol equipment may include, but is not limited to – switch gear, metering, over-temperature, open-circuit, short-circuit, overload protection;
adjustments include, but are not limited to – phase rotation, polarity.
5.5Commissioning confirms off-load and on-load operation of machine in accordance with specifications.
Rangedirection of rotation, vibration, temperature rise, current draw.
Replacement information / This unit standard has been replaced by unit standard 29444.This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.
Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 26 May 2005 / 31 December 2021
Rollover and Revision / 2 / 15 March 2012 / 31 December 2021
Revision / 3 / 15 January 2014 / 31 December 2021
Review / 4 / 21 July 2016 / 31 December 2021
Consent and Moderation Requirements (CMR) reference / 0003
This CMR can be accessed at
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.
The Skills OrganisationSSB Code 100401 / New Zealand Qualifications Authority 2018 / / New Zealand Qualifications Aut