BTEC Assignment Brief
Pearson BTEC Level 3 National Extended Certificate in Applied Science
Pearson BTEC Level 3 National Foundation Diploma in Applied Science
Qualification
Pearson BTEC Level 3 National Diploma in Applied Science
Pearson BTEC Level 3 National Extended Diploma in Applied Science
Unit number and title Unit 15: Electrical Circuits and their Applications
C: Examine AC and DC production and health and safety aspects in
Learning aim
domestic and industrial applications
Assignment title AC/DC
Assessor
Issue date
Hand in deadline
You are a trainee laboratory technician working for a local aluminium
smelting works. Like many large industries, the smelting works is a
huge consumer of electricity and has its own electrical generating
plant in the form of a hydroelectric plant. This sends excess
Vocational Scenario or electricity to the National Grid which, in turn, distributes it to local
Context homes. The plant also has an induction furnace to produce
aluminium ingots after the aluminium has been smelted. As part of
your training, you have been asked by the Health and Safety
committee of the company to develop an electrical safety awareness
booklet for their employees.
Prepare a booklet titled ‘Electrical Safety Awareness’ that has the
following sections:
Section 1 – AC and DC current
Explain the differences and similarities of the properties of AC and
DC current in simple circuits
Use diagrams based on simple laboratory experiments to
Task illustrate how both AC and DC electricity are produced
Carry out simple practical activities to produce both DC and AC
electricity and record your findings.
Explain, using diagrams, how Fleming’s Left-Hand Rule (FLH)
applies to electric motors and how Fleming’s Right Hand Rule
(FRH) applies to AC generators.
Discuss the need for a split ring commutator in a DC motor.
Describe how DC electricity can be stored.
Illustrate, with a fully labelled graph, the difference between
AC and DC electricity as seen using an oscilloscope.
Using your AC graph, add an appropriate scale on the
vertical axis and label the ‘peak voltage value’ and ‘RMS
voltage value.’ Explain why RMS voltage value is more
useful than the peak value. Show, by calculation, the peak
voltage value if the effective voltage value in the UK is
230V.
Section 2 - Effects of AC and DC electricity on the human
, physiology
In the context of the dangers of working with electricity, use a
diagram of the body to illustrate specific points and supplementary
notes to explain:
The typical resistance values or current pathways in the
body. What are the implications of this and is it different for
AC compared to DC electricity?
The consequence of skin resistance in different conditions
e.g., in contact with the ground, when moist
The effect of the length of current exposure time and the
amount of electrical current. How is this different for AC
compared to DC electricity?
The safe levels of DC voltage
How the heart responds to electric shock and how is this
applied to the principles of a defibrillator
Section 3 - The National Grid
Explain, with the aid of diagrams, how AC electricity is produced in an
electrical generator facility for use in homes and industry. Apply the
fundamental aspects of Fleming’s right hand rule for the generator in
the power station. You should include:
a reasoned argument as to why a high voltage AC generator
should be used rather than a low voltage turbine driven
dynamo
Describe how AC electricity is transferred from the hydroelectric plant
to homes and industry.
Mathematically account for the need of transformers and high
voltages. You should include:
the required voltage for applications of AC electricity around
the home and at the smelting plant.
the mathematical comparisons of energy/power loss of
transmitting electricity at different voltages
Produce a qualitative, reasoned argument which identifies why:
the voltages used to transmit electricity through the national
grid for a variety of uses, have been selected and why they
may be different at different points in the transfer system
components such as transformers are required in specific parts
of the national grid and connections between the hydroelectric
plant and the National Grid.
4) Using AC and DC electricity around the home
Discuss the principles of the ring main circuit found in houses. You
should include:
what is the purpose of the residual current and earth leakage
circuit breakers (RCCB and ELCB), and how do they operate?
kettles and hairdryers are often ‘double insulated,” what is the
significance of this?
how do fuses and miniature circuit breakers (MCB’s) work in
domestic appliances and why are they necessary?
when using DC equipment such as tablets, games consoles and
mobile phones, discuss the principles behind ‘charging them
up’ from the AC mains supply.
what are the dangers and inbuilt safety? (NB whilst these
questions give guidance to the range of considerations you
, should discuss, you must present this in a coherent way.)
Section 5 - Using AC and DC electricity in industry
It is essential that the smelting works protects its workers by applying
the Electricity at Work Regulations 1989. Discuss the specific actions
that should be taken and the safety devices that should be used to
protect workers when operating and repairing the AC and DC
equipment in the plant.
Checklist of evidence An electrical safety awareness booklet that has the following content:
required An explanation of the differences and similarities of the
properties of AC and DC current in simple circuits.
A comparison of the route means square (RMS) and peak
voltage for AC electricity in a simple circuit.
An explanation of the effects and dangers of AC and DC
electricity on human physiology.
An evaluation of the principles of AC production and
transmission for safe use in the context of providing AC
electricity for suitable uses in the home and aluminium
processing plant via the National Grid and its connection to the
hydroelectric facility.
A discussion of procedures and practices used to minimise risk
when working with electricity in the home and industry.
Criteria covered by this task:
Unit/Criteria
To achieve the criteria, you must show that you are able to:
reference
Evaluate the principles of AC production and transmission for safe use in suitable
C.D2
applications
C.M3 Compare RMS and peak values of AC electricity
Discuss procedures and practices used to minimise risk when working with
C.M4
electricity
C.P3 Explain the similarities and differences of AC and DC electrical circuits
Explain the dangers of working with electricity and its effects on human
C.P4
physiology
Sources of information http://www.hse.gov.uk/pUbns/priced/hsr25.pdf
to support you with
this Assignment http://www.inbrief.co.uk/employees/electricity-at-work/
Centres are encouraged to include local employers in delivery by
asking them to give guest lectures and provide opportunities for
industrial visits and work experience.
Other assessment n/a
materials attached to
this Assignment Brief
Alternating current – when the current goes back and forth changing direction
Direct current – when the current flows in one direction
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