Final draft GRADED UNIT REPORT 5THMAY (1) (1) (1) (Repaired) - for merge

RENEWABLE ELECTRICAL LIGHTING SYSTEM NICOLA COCHRANE
Renewable Electrical
Lighting System
Graded Unit 2 Project Report
Nicola Cochrane 5/21/15 HND Electrical Engineering

Renewable Electrical Lighting System Nicola Cochrane
1
SUMMARY
A renewable electrical lighting system is required for implementation in a small
caravan or motor home. The renewable energy will be sourced through the
application of a wind turbine and a PV cell which will operate to charge a 12V
battery. The battery, which acts as an energy storage device, will drive a
230/240V AC, 50Hz lighting circuit. The system also incorporates a full wave
bridge rectifier with regulator circuit, a DC to AC inverter circuit, a consumer
unit, a two-way switch and a small lighting circuit consisting of two junction
boxes and two light fittings.

2
TABLE OF CONTENTS
Summary .......................................................................................................1
Introduction ...................................................................................................5
Project Brief...................................................................................................6
Project Specification.......................................................................................7
Electrical Parameters...................................................................................7
Three Phase 12 V Wind Turbine Output Voltage .......................................7
12 V PV Cell Output Voltage...................................................................7
Full wave Bridge Rectifier with Regulator Circuit Input / Output Voltages..7
12 V Battery Input / Output Voltages........................................................7
DC to AC Inverter Circuit Input / Output Voltages ....................................7
DC to AC Inverter Circuit Frequency .......................................................7
230/240 V AC Lighting Circuit ................................................................7
Environmental Parameters...........................................................................8
Safety.....................................................................................................8
Waterproofing.........................................................................................8
Physical Characteristics...............................................................................8
Size ........................................................................................................8
Power Indicator.......................................................................................8
Battery Connections ................................................................................9
PV Cell...................................................................................................9
Wind Turbine..........................................................................................9
Project Objectives and Schedule ....................................................................10
Solution Analysis and Justification ................................................................12
Block Diagram .............................................................................................14
Technical Description ...................................................................................15
Three Phase to Single Phase Conversion ....................................................15
Power Rectification...................................................................................15
Voltage Regulation ...................................................................................15
Power Inversion........................................................................................15
Power Distribution....................................................................................15

3
Wind Turbine ...........................................................................................16
Three Phase to Single Phase Conversion ....................................................16
PV Cell....................................................................................................16
Full Wave Bridge Rectifier Circuit w/ Regulator & Smoothing Capacitor.....17
Battery.....................................................................................................17
DC to AC Inverter....................................................................................17
Lighting Circuit ........................................................................................18
Implementation ............................................................................................19
Overcoming Problems...............................................................................19
DC to AC Inverter Circuit .........................................................................20
Implementation Checklist..........................................................................21
Progress Reports...........................................................................................22
Verification Strategy.....................................................................................25
Full Wave Bridge Rectifier........................................................................25
Battery.....................................................................................................26
DC to AC Inverter....................................................................................26
Costing ........................................................................................................28
Materials..................................................................................................28
Labour and Service ...................................................................................28
Safety..........................................................................................................29
Main Operational Safety Standards ............................................................29
Safety Devices..........................................................................................29
MCB....................................................................................................29
RCD.....................................................................................................30
Discussions and Conclusions .........................................................................31
Acknowledgements ......................................................................................32
References ...................................................................................................33
Appendices ..................................................................................................34
Appendix 1 – Three Phase to Single Phase Conversion................................35
Appendix 2 – Full Wave Bridge Rectifier Output Waveform .......................36

4
Appendix 3 – Mosfet Output Waveform.....................................................37
Appendix 4.0 – Original DC to AC Inverter Schematic Including Mosfets
(Designed on Express PCB).......................................................................38
Appendix 4.1 – Re-designed DC to AC Inverter Schematic Excluding Mosfets
................................................................................................................39
Appendix 5 – DC/AC Inverter – IC chip – Logic Table ...............................40

5
INTRODUCTION
My client Charlie Watson, a member of the Caravan Club, approached my
employer, Green Electrical Installations requesting an electrical lighting system
powered by renewable energy sources for a small caravan or motor home.
Mr. Watson, who is in the early stages of retirement, is in the process of planning
an extended caravan vacation. As an environmentalist who owns a completely
passive, energy-efficient home, Mr. Watson is seeking to make adjustments to his
motor home in order to reduce his carbon footprint further.
My client has highlighted severalstipulations in relation to the design parameters
of the installation;
 System must be efficient
 System must be safe
 Energy source must be renewable i.e. Wind or solar
 Installation must include a minimum of two luminaires with room for
expansion

6
PROJECT BRIEF
In order to produce a safe and sustainable system, sufficient safety features,
power rectification, voltage regulation and power inversion must be incorporated
along with a storage device to ensure safe,efficient operation of the installation
and security of supply.
Renewable wind and solar energy are required to charge a 12 V battery which in
turn must safely operate a lighting circuit, requiring a power input of around 230
V AC at 50 Hz.
As project engineers, my colleague, Martin McNulty and I have been assigned
and are responsible for the design, construction and testing of the renewable
electrical lighting system as agreed with Mr. Watson.
Mr. Watson is satisfied with our proposal and stipulated a budget of £2,000. The
total cost of the project has come under budget at £1652.36, with materials priced
at £ 552.76 and labor charged at £999.60, presenting a budget reduction of
£347.64. My client requires the project to be completed by 05/06/15.

7
PROJECT SPECIFICATION
This specification details the main electrical and environmental parameters of
the renewable electrical lighting system. All systemcomponents must ONLY be
operated within the following specified parameters to ensure that the installation
functions safely and without posing risk to systemusers.
ELECTRICAL PARAMETERS
Three Phase 12 V Wind Turbine Output Voltage
The turbine output voltage will vary dependant on wind speed, ranging from 6 V
– 15 V. However,under optimum operating conditions the turbine will emit 12 V
AC (±5%).
12 V PV Cell Output Voltage
The PV cell will have restricted operating times as due to its necessity for solar
energy, the cell will only function during daylight hours, producing a constant 12
V DC output under normal operating conditions.
Full wave Bridge Rectifier with Regulator Circuit Input / Output
Voltages
The full wave bridge rectifier circuit will require an input voltage range of
between 10 V – 30 V AC in order to perform rectification and regulation to
provide the desired output voltage of 12 V DC (±5%). The input voltage must
not exceed 35 V as the regulator will cease to function correctly beyond this
voltage.
12 V Battery Input / Output Voltages
The battery will require a constant 12 V DC (±5%) input voltage to charge
effectively and emit an output voltage of 12 V DC (±5%) under normal
operating conditions. The output voltage may vary, outside of normal operating
conditions, according to the charge level of the battery.
DC to AC Inverter Circuit Input / Output Voltages
The inverter circuit requires a minimum input voltage of 12 V DC (±5%) to
function correctly and provide an output of 240 V AC (±5%). The input voltage
must not fall below 10 V DC or exceed 14 V DC for full functionality of the
circuit under normal operating conditions.
DC to AC Inverter Circuit Frequency
The inverter requires a frequency of 50 Hz to operate effectively under normal
operating conditions.
230/240 V AC Lighting Circuit
The lighting circuit requires a minimum input voltage of 230 V AC at a
frequency of 50 Hz but can continue to operate efficiently, energising the 15 W
light bulbs with an input of 240 V AC.

8
ENVIRONMENTAL PARAMETERS
Safety
The consumer unit which hosts the live, neutral and earth connections for the
lighting circuit is fitted with several safety features including supply switches,
MCBs (miniature circuit breakers) and RCDs (residual current devices) all of
which can operate to interrupt the circuit under fault conditions. These safety
devices provide over current and earth leakage protection to system components
and protection against electric shock to system users.
Two switches are also incorporated in the system as safety features and are
connected between the following system components to permit interruption of
the circuit out with normal operating conditions or for maintenance purposes:
- Full wave bridge rectifier circuit and battery
- Battery and inverter circuit
The system has been designed and constructed in accordance with all relevant
safety standards of BS 7671: 2008.
Waterproofing
The wind turbine and PV cell are both designed specifically for use in external
applications such as caravan installations, therefore hold certification indicating
waterproof protection which can be identified on the label of each component.
The PV cell selected for the system includes a protective enclosure which will be
mounted internally and contain the 12 V battery, along with the switches and full
wave bridge rectifier circuit. Mounting internally provides protection from bad
weather conditions and permits ease of access. The container has a door that is
key operated, which will help to minimise unwanted interference of the system in
the event that someone unknown/unskilled attempts to access/alter it.
The inverter circuit complete with heat sinks and transformer will be housed in a
separate protective enclosure which also includes a key-operated door and will
also be mounted internally for additional protection from severe weather
conditions and to allow ease of access.
PHYSICAL CHARACTERISTICS
Size
The protective PVC casing in which the full inverter circuit including the
transformer will be housed, is 400 mm long, 300 mm wide with a depth of 200
mm.
Power Indicator
The inverter circuit includes a power indicator in the form of an LED (light
emitting diode) which illuminates during operation and de-energises when the

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circuit is not conducting. The unit in which it is encased has a small window
through which the power indicator can be visually identified.
Battery Connections
Battery connections are formed using crimpled ring terminals for secure
connections. The cables are insulated and colour coded to avoid confusion, black
for the anode and red for the cathode.
PV Cell
The PV cell itself will be mounted flat and externally on the roof of the caravan.
Wind Turbine
The turbine will also be mounted externally on the roof of the caravan by means
of a nut and bolt. This is sufficient due to the small yet highly ergonomic
proportions of the turbine.

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PROJECT OBJECTIVES AND SCHEDULE
 Locally accessible components and materials will be utilised to modify
the researched inverter and rectifier circuits.
 Initial energy to operate the system must be renewable.
 The system is constructed to utilise renewable energy in order to provide
230-240 V AC at a frequency of 50 Hz when powered by a 12 V DC
source.
 Each system component must be tested and improved until it satisfies the
client’s requirements.
 All project operations must be conducted safely and in accordance with
the IET Wiring Regulations BS7671, the Electricity at Work Act 1992,
the Health and Safety at Work Act 1974 and all other relevant safety
standards.
 The project must be completed and submitted to the client within the
agreed timescale.
 The total project cost must exist within the client’s specified budget.
 The project must be completed in accordance with Electrical
Engineering: Graded Unit 2. Graded Unit Code: DN3X 35.
 The final project submission must include a project report, a log book
and a presentation, all of a very high standard to present to potential
future employers.

11

12
SOLUTION ANALYSIS AND JUSTIFICATION
The main parameters stipulated by my client are the utilization of renewable
energy to produce 230 V AC at 50 Hz for operation of a lighting circuit. The
system must be operable in remote settings, without dependence on a mains
power supply and must function efficiently with appropriate safety features.
The main system components have remained the same apart from a few
additional electronic components and some minor changes to circuit designs and
layouts. However there have been severaloptions to deliberate in regard to the
energy source required to operate the system. Subsequently, a hydroelectric
system was considered along with a windmill powered motor system that
incorporated a dump or diversion load. The selected renewable system
incorporating a wind turbine and PV cell was also considered.
To ascertain which system would be selected for the application, the following
parameters were identified, revised and explored in some detail with the client:
 Eco-friendly
 Efficiency
 Cost
 Suitable for implementation in a caravan
 Reliability
 Safety
 Discreet operation
 Aesthetically pleasing
 Portability
Extensive discussion with the client revealed that the necessity for portability of
the system is more important than initially discussed. The client has recently
been approached by a fellow member of the Caravan Club with an exceptional
financial offer for the purchase of his motor home. Although the client has
postponed the possibility of the sale for one year, this deems the requirement of a
portable system vital. Immediately, this eradicates the hydroelectric system from
potential options as that would remain static in the site in which it would be
erected. To determine which system adheres most appropriately to the specified
parameters,a resolution table shall be constructed.

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Parameters Windmill Wind turbine & PV cell
Eco-friendly 10 10
Efficient 5 8
Cost 7 8
Caravan suitability 8 10
Reliability 7 8
Safety 6 9
Discreet operation 7 9
Aesthetically pleasing 4 10
Portability 5 8
Total 59 80
The analysis clearly demonstrates that the combined system of a wind turbine
and PV cell is favorable as it gains the greatest number of points. The table
assists in determining a convenience factor which strongly supports the wind
turbine and PV cell option due to high ratings for all parameters,especially
portability, eco-friendliness and caravan suitability. Although the windmill
powered system is eco-friendly, it does not hold enough merit for efficiency,
safety and portability. This indicates potential power losses, a lack of safety
features which could result in damage to equipment or harm to system users and
an inability to relocate the system intact from one caravan to another. In terms of
aesthetic value, the windmill would also be fairly obtrusive compared to the
alternative system.
The wind turbine and PV cell system has been selected as it matches the criteria
set by the client more substantially than the other options.

14
Wind
Turbine
BLOCK DIAGRAM
PV Cell
Full Wave Bridge
Rectifier with
Regulator Circuit
Battery
DC to AC Inverter Circuit
Consumer Unit and Lighting Circuit

15
TECHNICAL DESCRIPTION
Please referto references [1-11] and appendices foradditional information.
THREE PHASE TO SINGLE PHASE CONVERSION
o The wind turbine is connected in star and provides a three phase output.
The connections are rewired into a delta configuration and with the aid of
a terminal slip, a capacitor is added across two phases to convert the
output from three phase to single phase.
POWER RECTIFICATION
o The wind turbine provides an output of approximately 10-12 V AC. This
passes through the full wave bridge rectifier chip which encases the 4 x
diode bridge rectifier formation and produces a rough 10-12 V DC.
o The added smoothing capacitor yields a higher output voltage and creates
a more constant and consistent DC output voltage, also known as a ripple
voltage.
VOLTAGE REGULATION
o The 7812 Regulator chip incorporated in the rectifier circuit regulates the
voltage, providing the desired output of 12 V DC required to charge the
battery.
POWER INVERSION
o The DC to AC inverter, designed on Express PCB software, will be
powered by 12 V DC from the battery. The circuit utilizes an IC
(Integrated Circuit) chip which acts as a controller, generating the duty
cycle of the mosfet components which are attached to separate heat sinks.
A step-up transformer completes this circuit, inverting the input voltage
to around 230 V AC at 50 Hz.
POWER DISTRIBUTION
o The consumer unit will safely distribute around 230 V AC at 50 Hz to
each lamp.

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WIND TURBINE
[1] Wasser Generator Wind Turbine. Manufactured by Ista Breeze.
 Model – i-500G
 Rated Output – 400 W
 Peak Output – 500 W
 Rated Voltage – 12 V AC
 Rated Charging Current – DC 41.7 A
 Operating Temperature Range (℃) – From -40° to 60°
 Over speed Control – Electromagnetic brake with Controller
 Generator type – Brushless 3-phase PMA with high performance
Neodymium Magnets
 Weight – 2kg
 Product Life – 15 years
 Warranty – 2 years
THREE PHASE TO SINGLE PHASE CONVERSION
(Appendix 1)
 Capacitor - 10𝜇F
 Terminal slip
PV CELL
[2] 10 W Solar System. Manufactured by Connexa.
 Rated Output – 10 W

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 Rated Voltage – 12 V DC
 25 years limited power output warranty
 Cells are laminated with TPT and EVA
ensuring longer life and maximum
performance
 Battery included
 High transparent low-iron, tempered glass
 Heavy-duty anodized frames
 Outstanding low-light performance
 Rugged design to withstand high wind pressure,hail and snow
FULL WAVE BRIDGE RECTIFIER CIRCUIT W/REGULATOR &
SMOOTHING CAPACITOR
 Vero board
 Bridge Rectifier Chip – KBP2008G [5]
 Regulator Chip – 7812 [7]
 Smoothing Capacitor – 100𝜇F
BATTERY
[6] Included in the solar system.
 12 V DC,18 A
DC TO AC INVERTER
(Refer to Appendix 4 for original and re-designed schematics.)
 PCB
 IC Chip: CD 4047 [9]
 Capacitors: 2200 𝜇𝐹, 0.1 𝜇𝐹
 Resistors: 33 kΩ, 330 Ω, 1 kΩ, 2 x 220 Ω
 Potentiometer: 100 kΩ
 Diodes: IN4007, LED
 Mosfets: 2 x IRF540 [8]

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 Transformer: Step-up, turns ratio - 1:20
 Flying leads
 Fixing pins
 Heat sinks: MDF, 2 x aluminium plates.
LIGHTING CIRCUIT
 Consumer unit: Wylex - 230 V AC 50Hz [3]
 Two-way switch
 2 x Light fittings [4]
 2 x 15 W light bulbs
 2 x junction boxes [10]
 Twin and earth cable

19
IMPLEMENTATION
In order to ensure efficient operation of the project in all stages,my colleague
and I demonstrated our organizational skills by dividing the tasks equally
between us both. On encountering a problem we worked as a team to carry out
research from a range of sources including books, websites, research papers and
advice from other engineers, enabling us to resolve issues competently and
rapidly. We implemented the knowledge gained from research by developing our
project. My colleague and I have maintained a high level of communication with
each other and the client throughout the duration of the project by arranging and
attending regular meetings. This has enabled us to discuss the project
development and also the problems we have encountered in order to fully agree,
with the client, on each of the steps taken to resolve them. We have remained
focused on the projects objectives, taking into account any suggestions or
alterations proposed by the client.
The following table highlights how the main tasks were distributed between both
my colleague and I;
Component Nicola Cochrane Martin McNulty
Lighting circuit Design/Construction Construction
Rectifier/Regulator Design Construction
PCB (1st
attempt) Construction Design
PCB (2nd
attempt) Construction Design
PCB (3rd
attempt) Construction Design/Construction
All minor electronic and electrical components required for construction of the
project were made readily available to us in the Green Electrical Installations
workshop. The heat sinks were hand-crafted using recycled materials.
OVERCOMING PROBLEMS
We encountered a variety of problems throughout the construction phase of the
project. Each issue we tackled assisted us in establishing an understanding of
unfamiliar components and a greater understanding of other known topics.
LIGHTING CIRCUIT
The first issue we encountered was unwanted power reduction in the lighting
circuit. We recognized there was a problem as during testing, the light bulbs were
not illuminating fully. After researching lighting circuits we understood that the
reason for this was due to the fact that we had connected the circuit in series.
Series lighting circuits distribute power by dividing the power equally by the
number of luminaires; therefore the more luminaires present in the circuit, the
dimmer the illumination from each lamp will be. To rectify this issue we re-

20
connected the lighting circuit in parallel which eradicated the unwanted power
reduction and allowed maximum power to flow to each luminaire.
DC TO AC INVERTER CIRCUIT
There were severalproblems with this circuit due to our unfamiliarity of several
of the electronic components.
Our initial problem arose from the wrong pin configuration of the IC CD4047
chip on the originally designed PCB. Having constructed the circuit and soldered
the components, we began testing with a logic probe. The logic probe identified
an issue with the pin configuration as we were not achieving the results expected
for each individual pin. To overcome this problem, we researched the CD4047
pin configuration on a variety of websites to ensure accuracy then my colleague
re-designed the PCB.
Secondly, after I started to solder the components into the re-designed PCB,we
were advised by an electronics engineer to create heat sinks for the mosfet
components to allow for heat dissipation. The heat sinks could not be attached to
the mosfets whilst connected to the PCB as we had not factored this possibility
into the design process,so there was not sufficient space to do so. We managed
to resolve this problem by constructing separate heat sinks from MDF and two
aluminium plates, creating a larger surface area for heat dissipation. Aluminium
was selected for its low resistivity and high dissipation values. We then excluded
the mosfets from the third and final PCB design.
Our final issue with the DC to AC inverter circuit occurred post construction and
soldering of the circuit. Upon testing the output voltage, frequency and waveform
of the circuit with an oscilloscope, we identified that the frequency was
extremely high, around 1.2 kHz and the voltage was exceptionally low at
approximately 500 mV. Such a high frequency would create harmonics through
the transformer when on load which is highly undesirable. We determined that
the 390 kΩ resistor was the cause of such a high frequency, so we replaced this
with a decade resistor in order to vary the resistance and achieve the desired
frequency of 50 Hz at around 12 V AC (prior to connection of the transformer).
From this, we were able to distinguish that the resistance required in place of the
390 kΩ resistor was 33 kΩ. We then replaced the decade resistor with a 33 kΩ
resistor and tested the outputs again with an oscilloscope. Fortunately we
achieved the ideal results.

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IMPLEMENTATION CHECKLIST
1 Reports and discussions with the client are clear and well
informed.
2 Progress reports identify completed tasks,progress made and
goals for future work.
3 Effective action is taken when feedback is received from the
client.
4 Additional expertise is identified and acquired when
necessary.
5 Adjustments are made to the schedule when appropriate and
with the agreement of the client.
6 Clear documents including the log book are maintained.

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PROGRESS REPORTS

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PROJECT ENGINEER: Nicola Cochrane
Project Supervisor: Charlie Watson
PROJECT TITLE Renewable Electrical Lighting System. Date 05/05/15
No. Item Checked
1
Progress to Date:
Full system construction is complete along with testing. First half of
report is also complete.
2 Actions since last Report:
Altered the time constant by changing the value of resistor in order to
achieve a frequency of 50Hz. Removed MOSFETS from PCB and
connected to heat sinks. Simulating Turbine.
3 Problems Overcome and Outstanding:
Frequency out from the MOSFETS was too high but the problem was
overcome. Addition of switches for safety
4
Next Actions and Goals:
Complete report and presentation.
5
Log Book up to Date:
Yes
6
Current Documentation Provided:
Log Book
7 Supervisor’s Comments:

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PROJECT ENGINEER: Nicola Cochrane
Project Supervisor: Charlie Watson
PROJECT TITLE Renewable Electrical Lighting System. Date 20/01/15
No. Item Checked
1
Progress to Date:
Selected project, researched circuits, built full bridge wave rectifier
circuit with smoothing capacitor and regulator, started construction on
lighting circuit, altered DC to AC inverter circuit.
2 Actions since last Report:
N/A
3 Problems Overcome and Outstanding:
Initially connected lighting circuit in series but power to the lights was
reduced so rearranged and connected in parallel, to avoid this problem.
4
Next Actions and Goals:
Finish constructing lighting circuit, order parts for the inverter and
design the wind turbine.
5
Log Book up to Date:
Yes
6
Current Documentation Provided:
Log Book
7 Supervisor’s Comments:

25
VERIFICATION STRATEGY
Testing and evaluation are vital aspects of every engineering project. These
processes are consistent throughout the development of the project as every stage
must be compared with and adhere to the project objectives and the customer’s
specifications.
The verification strategies and results of each component of the project were as
follows:
Methods of testing included:
 Visual inspections of each circuit at every stage of construction.
 A multimeter was utilized for testing continuity and output voltages.
 An oscilloscope was used to verify the output waveforms and frequency
of the circuits.
 A logic probe was utilized to test the IC chip.
FULL WAVE BRIDGE RECTIFIER
Results for each test were as follows:
o Visual inspections – Ensured that components were positioned correctly
and soldered to a good standard, allowing for full functionality and safe
operation of the circuit.
o Continuity tests were performed prior to any testing which involved the
multimeter. All continuity tests were successfulas the multimeter
measured 0Ω of resistance each time.
o Rectifier/Regulator Output Voltage – 12.25 VDC:
This demonstrates that the circuit is operating correctly as 12 V AC is
flowing into the circuit, there is a 1.4 Voltage drop across the rectifier as
each diode has a volt drop of 0.7 V and two diodes operate at any one
time. This brings the voltage to around 10.6 V DC (±5%) which then
passes through the smoothing capacitor yielding a higher output voltage
and finally through the regulator which emits a constant DC voltage of
12 V (±2.5%).
o Rectifier output waveform:As expected: [11] (Appendix 2)

26
o Regulator output waveform: As expected:Constant 12 V DC output.
BATTERY
The output voltage of the battery was tested with a multimeter:
Output voltage – 12.53 VDC:This demonstrates that the battery is fully
charged and is operating correctly.
DC TO AC INVERTER
Results for each test were as follows:
o Visual inspections – Ensured that components were positioned correctly
and soldered to a good standard, allowing for full functionality and safe
operation of the circuit.
multimeter. All continuity tests were successful as the multimeter
o Logic probe test results table for IC CD4047: (Appendix 5)
Results were as expected.
o Dummy load – Prior to connection of the center-tapped transformer, the
inverter was tested by connecting a dummy load consisting of two 330Ω
resistors in series across the output. The resultant output was around
13.85 V as expected. This enabled us to verify that the circuit was
operating safely. Please refer to Appendix 3 for mosfet output waveform.

27
Figure 1.0 – Inverter testing with dummy load
o Inverter Input / Output Voltages:
Input voltage – 12.24 VDC
Output voltage – 168 Vrms AC
The output voltage measurement was taken from the live and neutral of
the consumer unit. In order to calculate the peak voltage (Vp) the rms
voltage must be multiplied by √2 as follows:
Vp = 168 x √2
= 238 Vp AC
Since the voltage required to operate the lighting circuit is 230-240 Vp
AC, 238 V AC is ideal and as expected.
LIGHTING CIRCUIT
Test results were as follows:
o Visual inspections – Ensured that components were wired correctly and
corresponding safety devices were positioned appropriately, allowing full
functionality and safe operation of the circuit.
multimeter. All continuity tests were successfulas the multimeter
o Live to Neutral – 170.8 VAC – 240 Vp AC As expected.
o Live to Earth – 0 V – As expected. The circuit is operating safely.
o Neutral to Earth – 0V – As expected. The circuit is operating safely.

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COSTING
The overall charge for the installation will be calculated and invoiced to the
client on completion of the project.
The costs involved in manufacturing the prototype can be divided into two main
parts:
 Materials
 Labour and service
MATERIALS
Green Electrical Installations are happy to subsidize the cost of minor
components as an incentive for our new client to approach us in the future with
any further renewable concepts.
The following table lists the price of each component and the total cost of
materials that will be charged to the client:
Component Price
Wind Turbine £98.50
PV Cell £445.50
Rectifier £1.99
Regulator £0.36
IC CD4047 £0.53
Mosfets £1.35
Lamps £3.48
Junction boxes £1.05
TOTAL £552.76
LABOUR AND SERVICE
These costs will be broken down into two parts,company cost and physical
labour charge.
Green Electrical Installations will charge a service cost of £100 due to the
necessity for a prototype to be created prior to production of the finalized system.
This installation required additional time and attention compared to our pre-
fabricated systems which validates the service cost.
My colleague and I are paid an hourly rate of £14.28 and spent 35 hours each
working on the installation. The total cost of labour is calculated as £999.60.
This brings the overall cost of the project to a total of £1652.36, which has been
agreed fully with the project supervisor and the client.

29
SAFETY
As an employer, Green Electrical Installations are fully liable for ensuring that all
employees operate within the boundaries of current safety legislation and adhere
fully to all IET Wiring Regulations.
MAIN OPERATIONAL SAFETY STANDARDS
Throughout the construction phase of the project, my colleague and I abided
strictly by the following fundamental safety standards:
 Goggles must be worn during participation in any drilling/soldering
activities and also when operating in close vicinity of such activities.
 Earth wrist strap must be worn when handling components.
 Power supply to workshops and labs must be switched off if unattended.
 All components must be tested prior to implementation.
 All circuits must be tested individually and appropriately post
construction.
 Circuits must not be energized until testing is complete and satisfactory.
 Battery must remain isolated until testing and full system constructions
are complete.
The project supervisor signed off every stage of construction to verify that each
one was conducted safely and suitably.
SAFETY DEVICES
The consumer unit incorporates two different safety features which are detailed
below.
MCB
An MCB (Miniature Circuit Breaker) is an electromechanical device that
operates to protect the circuit and equipment from overload and fault conditions.
Figure 1.1 - MCB
The thermal operation of an MCB is achieved with a bimetallic strip in the event
that over current flows through the MCB, the bimetallic strip is heated and
deflects by bending. The deflection of the bimetallic strip releases a mechanical

30
latch. As the latch is attached with an operating mechanism, it opens the MCB
contacts. However,if a short circuit occurs, there will be a sudden increase of
current which causes electromechanicaldisplacement of the plunger associated
with the solenoid part of the MCB. The plunger strikes the trip level, resulting in
the release of the latch which again opens the contacts.
RCD
A residual current device is an electrical wiring device that operates to provide
protection to system users from electric shock. These devices can also be used as
a form of system protection against excessive heat.
Figure 1.2 – RCD schematic
These devices operate by detecting and interrupting earth fault currents that
equate to 50% or more of the rated tripping current.
The key component in these devices is a current transformer upon which the live
and neutral conductors are wound in opposite directions. There is a third winding
on the transformer which acts as a detector or search coil. If no fault current
flows then the live and neutral conductors will carry the same currents. Therefore
there will be no resulting flux in the current transformer for the detecting coil to
generate a current. When a fault current flows, a potential difference will exist
between the live and neutral conductors. This will generate a resultant flux which
will induce a current in the search coil. This, in turn, operates a relay or trip coil
which opens the main RCD contacts.

31
DISCUSSIONS AND CONCLUSIONS
The design process of the prototype broadened my understanding of design
software and my ability to simulate electronic circuits. I was also introduced to
severalelectronic components that I was previously unfamiliar with and gained
skills in implementing electronic circuits from schematic diagrams.
I gained a lot of valuable practical experience throughout the construction phase
of the system. This included installation of a small domestic lighting circuit,
constructing and soldering electronic and electrical components and fault finding
techniques, of which my knowledge has vastly increased. The use of a log book
to retain ideas, make notes and document results proved to be an important
reference guide.
My initial attempt at soldering left a lot to be desired. To improve my soldering
skills I approached the college technician for advice and was directed in how to
progress. Thereafter,I practiced soldering simple circuits onto vero board
including a relay and my technique improved substantially in a short period of
time. I was then a lot more confident in my approach to solder and continued to
complete the electronic circuits without any difficulties. I am now considering
purchasing my own soldering equipment to practice as a hobby.
Due to my unfamiliarity of certain components, I found electronics and fault
finding to be the most challenging aspects of the project as a whole. I found it
difficult to understand the operation of certain electronic components and
therefore, how to rectify faults from these components. However,with research
and good advice and direction from my lecturer, Charlie Watson, I was able to
gain a better knowledge and understanding of said components and how to detect
faults. From this experience I have achieved a greater ability to find and fix faults
using equipment such as logic probes.
Overall, I thoroughly enjoyed the project and I am satisfied that Martin McNulty
and I have successfully designed, constructed and tested a fully operational
system which adheres to the project objectives and specification. We
implemented our collective knowledge from modules such as; Electrical
installation design, DC/AC principles, Application of power electronics, Energy
overview, Digital electronics as well as the practical experience we gained in
completing an SVQ level 2 in Performing Engineering Operations last year, to
aid us throughout the whole process.
The knowledge and skills I have gained, both practically and theoretically, are
vital to my progression into University and ultimately into the engineering
industry on completion of my studies. I now have the confidence in myself as an
engineering student that I lacked prior to commencement of the project. This has
reaffirmed my passion for engineering and my motivation to succeed as an
engineer in the near future.

32
ACKNOWLEDGEMENTS
First and foremost I would like to thank my colleague, Martin McNulty for his
collaboration and support throughout the project.
I would also like to thank the all talented Charlie Watson. As client, lecturer, and
project supervisor, Mr. Watson had several roles in our project and fulfilled each
one expertly. Thanks for your guidance, confidence and perseverance Charlie.
Thank you to Gary Murray, the college technician, for all of his advice and
assistance throughout the difficult stages of the build and also for my new and
vastly improved soldering technique.
I would also like to thank Stuart Logan for his recommendations and reassurance
at severalpoints throughout the project completion.
Finally, thank you to all of the lecturers who have contributed to my progression
through the HNC and HND in Electrical Engineering. The knowledge and skills I
have gained with your assistance have enabled me to produce a successfulgraded
unit project.

33
REFERENCES
[1] Wind Turbine:
http://www.istapower.net/en/home/12-wassergenerator-windturbine-
istabreeze.html
[2] PV Cell:
http://www.cannonwater.net/Solar_Power_System_10watt.aspx
[3] Consumer Unit:
http://uk.rs-
online.com/web/p/product/569603/?grossPrice=Y&cm_mmc=UK%7CShopping-
_-Google+PLA-_-Wylex%7CConsumer+Units-_-
569603&kpid=&kpid=569603&istCompanyId=f7e7b05b-2daf-4c0e-8825-
3633baf8113b&istItemId=xwimtxtww&istBid=tzit&gclid=CKGmj9r3ncUCFQz
HtAodpWwA4w
[4] Light fittings:
http://www.diy.com/departments/crabtree-gloss-urea-batten-lamp-
holder/241874_BQ.prd
[5] Rectifier:
http://html.alldatasheet.com/html-
pdf/625893/JUXING/KBP2008G/217/1/KBP2008G.html
[6] 12V Battery:
http://www.slingsby.com/Workshop-Maintenance987/Power-
supply924/Batteries641/Rechargable-sealed-lead-acid-
batteries_386639.htm?gclid=CMjn5fT5ncUCFQcTwwodmL0ARA
[7] Regulator:
http://www.hobbytronics.co.uk/voltage-regulator-l7812
[8] Mosfets:
http://www.irf.com/product-info/datasheets/data/irf540n.pdf
[9] IC CD4047:
http://uk.farnell.com/texas-instruments/cd4047be/ic-4000-cmos-4047-dip14-
18v/dp/1106105
[10] Junction boxes:
http://www.diy.com/departments/marbo-20a-4-terminal-black-junction-
box/213554_BQ.prd
[11] Rectifier waveform:
https://www.sonoma.edu/users/m/marivani/es231/units/experiment_05.shtml

34
APPENDICES

35
APPENDIX 1 – THREE PHASE TO SINGLE PHASE CONVERSION
Figure 1.0 – Configuration from Star to Delta
Fig 1.1 – Re-wiring Star to delta
Fig 1.1 demonstrates how the star connections will be re-configured to a delta
formation. The delta configuration will continue to emit a three phase output. In
order to convert the output to single phase, a capacitor will be connected across
two of the three phases. This a better alternative to removing a phase as it ensures
prevention of power loss to the load. Great care must be taken in the selection of
a suitably rated capacitor, failure to do so may result in thermal damage of the
windings or in extreme cases,fire.
The capacitor will be connected to complete the three phase to single phase
conversion with the aid of a terminal block as demonstrated below:
Three phase in
Single phase out Capacitor connection

36
APPENDIX 2 – FULL WAVE BRIDGE RECTIFIER OUTPUT
WAVEFORM
This variation of the output voltage is called a Ripple. This particular ripple is
ideal as it flows smoothly without excessive variation. The ripple varies
depending on the load and also the value of capacitor used for smoothing
purposes. If the circuit is under heavy load and the load is demanding a large
current, the ripple will vary more, creating an excessive ripple effect. The same
excessive ripple will also occur if the value of capacitor is too small.

37
APPENDIX 3 – MOSFET OUTPUT WAVEFORM
The above waveform was measured from the output of the Metal-oxide-
semiconductor field-effect transistors, commonly known as mosfets during
operation of the system. The waveform demonstrates emission of an AC supply
from these voltage controlled switches. The square wave represents the on and
off switching periods according to the duty cycle set by the controller (IC chip) in
order to obtain the desired output voltage. The slightly sloping tops and bottoms
rare caused by low primary inductance, however this is not an issue as the slopes
are less than a few volts.

38
APPENDIX 4.0 – ORIGINAL DC TO AC INVERTER SCHEMATIC
INCLUDING MOSFETS (DESIGNED ON EXPRESS PCB)

39
APPENDIX 4.1 – RE-DESIGNED DC TO AC INVERTER
SCHEMATIC EXCLUDING MOSFETS

40
APPENDIX 5 – DC/AC INVERTER – IC CHIP – LOGIC TABLE
Pin Logic
1 Pulsating
2 Pulsating
3 Pulsating
4 Pulsating
5 Pulsating
6 Pulsating
7 Lo
8 Lo
9 Lo
10 Pulsating
11 Pulsating
12 Lo
13 N/A (No connection)
14 Pulsating

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