Apply intermediate principles of marine electrotechnology

This unit involves the skills and knowledge required to explain intermediate marine electrotechnology principles and perform intermediate electrical calculations.


This unit applies to the work of a Marine Engineer Class 2 on commercial vessels greater than 3000 kW and forms part of the requirements for the Certificate of Competency Marine Engineer Class 2 issued by the Australian Maritime Safety Authority (AMSA).


Not applicable.

Elements and Performance Criteria


Apply concepts of resistivity, resistance and capacitance to series and parallel AC and DC circuits


Calculations are performed to solve problems related to resistance, voltage drop, current and power in series and parallel circuits


Calculations are performed to solve problems related to temperature coefficient of resistance and change of resistance of a conductor with a change of temperature


Basic relationships that give total equivalent capacitance for capacitors arranged in series and parallel combinations are derived


Relationships that give total equivalent capacitance to solve numeric problems involving alternating current (AC) and direct current (DC) circuits are applied


Explain how principles of electrolytic action apply to electrical cells and batteries


Kirchhoff’s circuit laws are explained


Calculations to solve problems involving currents, voltage drop and terminal potential difference for cells connected to form batteries in series and in parallel are performed


Calculations to solve secondary cell charging and discharging problems are performed


Calculations to solve problems related to the efficiency of cells are performed


Analyse a magnetic circuit


Key parameters of magnetic circuits are identified


Formula for calculating the amount of flux generated by a multi turn solenoid coil carrying a current to give the B/H relationship is applied


Significance of the varying slopes in the B/H curves for a solenoid coil with air, cast iron, cast steel and mild steel cores is explained


How a magnetic circuit may be created by using a toroidal core within the solenoid coil is shown


Calculations to solve problems relating to magnetic circuits using different materials in different parts of their cores, including air gaps, are performed


Effect on flux density of applying an alternating magnetising force to an iron core is shown diagrammatically


Interpret electromagnetic consequences of a conductor moving relative to a magnetic field


Faraday’s and Lenz’s Laws are applied to solve problems relating to the electromagnetic induction of EMF and current


Generation of EMF is illustrated by a simple, single loop conductor rotating in a uniform magnetic field and how this EMF may be tapped to an external circuit as either AC or DC is explained


How alternating electrical quantities may be represented by rotating phasors is illustrated and explained


Relationships between instantaneous, maximum, average and RMS values of sinusoidally alternating electrical quantities is derived


Mathematical problems are solved by applying relationships between instantaneous, maximum, average and RMS values of sinusoidally alternating electrical quantities


Analyse circuits that incorporate combinations of resistive, inductive, and capacitive elements


Time constant for different circuit combinations subjected to DC EMF’s is defined


Calculations are performed to solve problems involving time constants in DC circuits with changing rates of current in resistive/inductive elements and changing voltages through resistive/capacitive circuit elements


Differentiation is made between inductive reactance, capacitive reactance and impedance as applied to AC circuits


Effects of inductive and capacitive reactance upon phasor relationships between applied AC voltage and current are shown


Concept of total impedance is applied to solution of problems involving single phase AC quantities in the presence of both resistive/inductive and resistive/capacitive circuit elements, arranged in either series or parallel


Power factor is defined and concepts of real and reactive power usage are applied to solution of problems involving RL and RC elements


Analyse operation of polyphase AC circuits


How three phase AC may be developed out of simple single phase AC is explained


Voltage and current relationships between line and phase in both Star and Delta 3 phase connections are derived


Standard Star to Delta and Delta to Star conversion relationships for current and voltage are derived


Numeric problems involving both balanced and unbalanced circuit loads are solved


Relationships between kW, kVA and kVAr for 3 phase AC circuits is derived


Calculations are performed using the relationship between kW, kVA and kVAr to solve problems in 3 phase AC circuits


Describe basic operating principles of shipboard DC machinery


Schematic circuits are prepared for separately excited, series, shunt and compound connected generators and motors to illustrate wiring arrangements used with DC machines


EMF equation for a DC generator to solve shipboard problems is applied


Torque equation for a DC motor to solve shipboard problems is applied


Expression linking back EMF parameters for a DC motor is derived and used to solve shipboard problems


Various losses that can occur in DC motors and generators are calculated


Perform calculations related to operation of AC generators


Construction features of the AC synchronous generator are explained


EMF equation for an AC generator is derived, taking into account distribution and pitch factors


Expression for the magnitude and speed of the rotating flux generated by a three-phase supply is derived


Voltage regulation for synchronous generator is defined


Effect of power factor on load characteristic of an AC generator is illustrated


Perform calculations related to operation of three-phase AC induction motors


Construction features of the AC induction motor are explained


Expression for slip of an induction motor rotor is derived and applied to frequency of its rotor EMF and current


Expression for magnitude of rotor EMF and current is derived, taking into account distribution and pitch factors


Relationships between rotor torque, rotor losses and slip indicating factors that affect torque are outlined


Significance of torque/slip curves for an induction motor is explained


Relationship between starting torque and applied voltage is established and consequences of this upon starting methods are outlined


Explain operating principles of basic electrical instrumentation


Schematic circuit diagrams are prepared that illustrate the main features and applications of moving coil and moving iron voltmeters and ammeters


Schematic circuit diagrams are prepared that illustrate the main features and applications of air and iron cored dynamometer type wattmeters


Dangers associated with current and voltage transformers on high current and voltage systems are identified

Required Skills

Required Skills:

Assess own work outcomes and maintain knowledge of current codes, standards, regulations and industry practices

Explain intermediate principles of marine electrotechnology

Explain Faraday’s and Lenz’s Laws of Electromagnetic Induction

Identify and apply relevant mathematical formula and techniques to solve problems related to marine electrotechnology

Identify and interpret numerical and graphical information, and perform mathematical calculations such as the relationship between starting torque and applied voltage in three phase AC induction motors

Identify, collate and process information required to perform calculations related to marine electrotechnology

Impart knowledge and ideas through verbal, written and visual means

Read and interpret written information needed to perform intermediate electrical calculations

Use calculators to perform mathematical calculations

Required Knowledge:

AC induction motors

AC principles


Circuit diagrams

DC motors

Difference between AC and DC




units of measurement




Intermediate electrical circuits

Kirchhoff’s circuit laws

Magnetic circuits

National and international maritime regulations, IMO Conventions and Codes applicable to the operation of electrical and electronic control equipment on vessels of typically unlimited propulsion power

Ohm’s Law

Polyphase AC circuits

Principles of:

electrical safety

electrolytic action


Parallel circuits

Principles and procedures for electrical and electronic measurement

Series circuits

Shipboard DC machinery

Work health and safety (WHS)/occupational health and safety (OHS) requirements and work practices

Evidence Required

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria, the required skills and knowledge, the range statement and the Assessment Guidelines for the Training Package.

Critical aspects for assessment and evidence required to demonstrate competency in this unit

The evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the Elements, Performance Criteria, Required Skills, Required Knowledge and include:

making accurate and reliable calculations

solving problems using appropriate laws and principles.

Context of and specific resources for assessment

Performance is demonstrated consistently over time and in a suitable range of contexts.

Resources for assessment include access to:

industry-approved marine operations site where intermediate principles of marine electrotechnology can be applied

electrical diagrams, specifications and other information required for performing intermediate electrical calculations

technical reference library with current publications on intermediate marine electrotechnology

tools, equipment and personal protective equipment currently used in industry

relevant regulatory and equipment documentation that impacts on work activities

range of relevant exercises, case studies and/or other simulated practical and knowledge assessments

appropriate range of relevant operational situations in the workplace.

In both real and simulated environments, access is required to:

relevant and appropriate materials and equipment

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

Method of assessment

Practical assessment must occur in an:

appropriately simulated workplace environment and/or

appropriate range of situations in the workplace.

A range of assessment methods should be used to assess practical skills and knowledge. The following examples are appropriate to this unit:

direct observation of the candidate applying intermediate principles of marine electrotechnology

direct observation of the candidate applying relevant WHS/OHS requirements and work practices.

Guidance information for assessment

Holistic assessment with other units relevant to the industry sector, workplace and job role is recommended.

In all cases where practical assessment is used it should be combined with targeted questioning to assess Required Knowledge.

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

Range Statement

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below.

Key parameters of magnetic circuit may include:



Flux density

Magnetising force

Magneto motive force

Circuit combinations may include:



Losses may include:

Copper losses

Iron losses or magnetic losses

Mechanical losses


Not applicable.

Employability Skills

This unit contains employability skills.

Licensing Information

Not applicable.