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TECHNICAL REPORT ON INDUSTRIAL TRAINING (SIWES) BY FAGOROLA
ENIITAN OLAWOLE
Technical Report · March 2021
DOI: 10.13140/RG.2.2.21358.33605
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A
TECHNICAL REPORT
ON
STUDENT INDUSTRIAL WORK EXPERIENCE SCHEME
(S.I.W.E.S)
UNDERTAKEN AT
MAGZONIK INVERTER AND SOLAR CO.
LIMITED
ONDO STATE INDUSTRIAL PARK ONYEARUBULEM MARKET AKURE,
ONDO STATE, NIGERIA
COMPILED AND SUBMITTED BY
FAGOROLA ENIITAN OLAWOLE
EEE/14/1695
TO THE
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING,
FEDERAL UNIVERSITY, OYE-EKITI,
EKITI STATE, NIGERIA.
IN PARTIAL FUFILMENT OF THE REQUIREMENT FOR THE AWARD OF BACHELOR OF
ENGINEERING (B.ENG), DEGREE IN ELECTRICAL AND ELECTRONICS ENGINEERING,
APRIL, 2019.
1|Page
DEDICATION
I dedicate this write up to Almighty God who made this program a success for me and my
lovely parents for their support and words of encouragement rendered to me during my industrial
training. Also, the entire staff of Magzonik Inverter and Solar Co. Limited for accepting me with
arms wide open undoubtedly. May God bless and reward you all Amen.
2|Page
ACKNOWLEDGEMENT
To God be the glory for allowing me through a very successful training. I will like to
appreciate and acknowledge my industry based supervisor, Engr Dauda Tijani Ahmed for taking
his time in explaining everything I found difficult to understand throughout my training. I specially
appreciate the field engineer, and all staffs of Magzonik Inverter and Solar Co. Limited, also to all
my institution lecturers in the department of Electrical and Electronics Engineering. I will like to
specially appreciate my parent for their Love, kindness and disciplinary support. I thank God for
the lives of my friends and fellow IT students for helping me through a stress free industrial
Training.
3|Page
ABSTRACT
One of the major advantages of the “The Student Work Experience Scheme” is to expose
students to life in the industries. I had my industrial training experience at Magzonik Inverter and
Solar Co. Limited. This report highlights the major experiences that I acquired during the period of
the industrial exposure at all the Department and unit, I participated in the production of inverter,
Installation of inverter, production of solar streetlight, Maintenance of Battery Banks, house wiring.
Every chapters explained the experience gathered at the company of my placement.
Some of the challenges I was confronted with include marrying theory with practical which is often
not evident at times. This situation led me to make personal research on the internet, personal
contacts and others. At the end of the training I look back with satisfaction having acquired so much
experience.
4|Page
TABLE OF CONTENTS
TITLE PAGE………………………………………………………………………………...……1
DEDICATION................................................................................................................................. 2
ACKNOWLEDGEMENT.............................................................................................................. 3
ABSTRACT ..................................................................................................................................... 4
TABLE OF CONTENTS ............................................................................................................... 5
LIST OF FIGURES ........................................................................................................................ 7
LIST OF TABLES .......................................................................................................................... 7
CHAPTER ONE ............................................................................................................................. 8
1.0
GENERAL INTRODUCTION ....................................................................................... 8
1.1
ABOUT INDUSTRIAL TRAINING FUND (ITF)........................................................ 8
1.2
ABOUT STUDENT INDUSTRIAL WORK EXPERIENCE (SIWES) ...................... 8
1.2.1
OBJECTIVE OF SIWES ............................................................................................. 8
1.3.0
COMPANY PROFILE ............................................................................................. 9
1.3.1
MAGZONIK INVERTER AND SOLAR CO. LIMITED .................................... 9
1.3.2
SOME OF THE OBJECTIVES OF THE COMPANY......................................... 9
1.3.3 ORGANIZATIONAL CHART .................................................................................. 10
CHAPTER TWO .......................................................................................................................... 11
2.0
AREAS OF EXPERIENCE........................................................................................... 11
2.1
POWER INVERTER..................................................................................................... 11
2.2
INVERTER PRODUCTION ........................................................................................ 14
2.2.1
THE TRANSFORMER .......................................................................................... 15
2.2.2
TRANSFORMER DESIGN CORE ...................................................................... 15
2.2.3
TRANSFORMER WINDING PROCESS ............................................................ 17
2.2.4 CALCULATION USED IN DESIGNING POWER INVERTER
TRANSFORMER ................................................................................................................. 17
2.2.5
MAKING OF BOBBIN/FORMER ....................................................................... 21
2.2.6
WINDING OF THE COPPER COIL ................................................................... 21
2.2.7
TESTING OF THE WOUND TRANSFORMER................................................ 22
2.3
THE OSCILLATOR AND DRIVER UNIT ................................................................ 22
2.3.1
DRIVER SECTION ................................................................................................ 23
2.4
INVERTER AUTOMATIC TRANSFER SWITCH (CONTROL UNIT)................ 25
2.5
PRODUCTION OF PACKING CASING ................................................................... 25
2.5.1
PRIMING ................................................................................................................ 25
2.5.2
BASE SMOOTHING.............................................................................................. 26
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2.5.3
AUTOBASE PAINTING........................................................................................ 26
2.6
INSTALLATION PROCESS ........................................................................................ 27
2.7
MAINTENANCE, SAFETY AND PRECAUTION .................................................... 27
2.8
SOLAR PANELS, INSTALLATION AND SOLAR STREET LIGHT ................... 28
2.9
SOLAR PANEL ............................................................................................................. 28
2.9.1
TYPES OF SOLAR PANEL .................................................................................. 28
2.9.2 IMPORTANT FACTOR CONSIDERED WHEN INSTALLING SOLAR
PANEL. .................................................................................................................................. 29
2.9.3
2.10.1
INSTALLATION OF SOLAR PANEL ................................................................ 29
SOLAR POWERED STREET LIGHT .................................................................... 31
2.10.2 PRODUCTION OF SOLAR STREET LIGHT ................................................... 31
2.10.3 CHARGE CONTROLLER ................................................................................... 32
2.10.4
MOLDING OF THE BASEMENT FOR THE STREETLIGHT POLES ....... 33
2.10.5 INSTALLATION OF THE SOLAR POWERED STREET LIGHT ................ 34
2.11
STORAGE (BATTERIES) ........................................................................................ 35
2.11.1
TYPES OF BATTERIES ........................................................................................... 35
2.11.2
VRLA: -……………………………………………………………...……………40
2.11.3
FLOODED BATTERIES (AIR VENTED) ......................................................... 35
2.11.5 VARIOUS CONNECTION OF BATTERIES ..................................................... 36
2.11.6
VARIOUS APPLICATION OF BATTERY ........................................................... 37
2.11.7
REVIVING OF FLOODED BATTERIES.............................................................. 38
2.11.8
HYDROMETER .................................................................................................... 38
2.11.9 PROCESS OF REVIVING A FLOODED BATTERY ....................................... 40
2.11.10
TESTING OF BATTERIES .................................................................................. 40
2.11.11
BATTERY RACK .................................................................................................. 41
CHAPTER THREE ...................................................................................................................... 42
3.0
CHALLENGES/PROBLEMS ENCOUNTERED AND THEIR SOLUTIONS .......... 42
CHAPTER FOUR ......................................................................................................................... 43
4.0
APPRAISAL, RELEVANCE TO EEE DISCIPLINE, & CONCLUSION .................. 43
4.1
APPRAISAL AND CONCLUSION: - ......................................................................... 43
4.2
RECOMMENDATION: ................................................................................................ 44
4.3 RELEVANCE TO EEE DISCIPLINE: ............................................................................ 44
4.3
REFERENCES: ................................................................................................................. 45
6|Page
LIST OF FIGURES
FIGURE 1:ORGANIZATIONAL CHART OF MAGZONIK INVERTER AND SOLAR CO. ........................ 10
FIGURE 2: PICTURE OF THE COMPANY PRODUCED INVERTER ............................................... 11
FIGURE 3:PICTURE OF DIFFERENT OUTPUT WAVEFORM...................................................... 12
FIGURE 4: FUNCTIONAL BLOCK DIAGRAM OF A TYPICAL POWER INVERTER .............................. 14
FIGURE 5: TRANSFORMER CORE CONSTRUCTION TYPE ....................................................... 15
FIGURE 6: DIFFERENT LAMINATIONS SIZE AND FIGURE 7: PICTORIAL OF THE ARRANGED E & I
LAMINA………………………………………………………………………………………………………………16
FIGURE 8:CENTER-TAPPED TRANSFORMER AND FIGURE 9:COMPLETELY WOUND TRANSFORMER 17
FIGURE 10: COMPLETELY GLUED TOGETHER FIBER BOBBIN ................................................. 21
FIGURE 11:COMPLETELY WOUND TRANSFORMER WITHOUT LAMINATION AND A COPPER COIL ..... 21
FIGURE 12:ASSEMBLED OSCILLATOR AND DRIVER UNIT...................................................... 22
FIGURE 13: PRINTED CIRCUIT BOARD………………………………………………………………………….23
FIGURE 14: DATA SHEET OF A MOSFET……………………………………………………………………….24
FIGURE 15: PRIMING OF CASING……………………………………………………………………………….25
FIGURE 16:AUTOBASE PAINTED CASING………………………………………………………………….....26
FIGURE 17:SOLAR PANEL UNDER TEST CONDITION ........................................................... 28
FIGURE 18:DIFFERENT TYPES OF SOLAR PANEL ................................................................ 28
FIGURE 19: PICTURE SHOWING BEST POSITIONING OF SOLAR PANEL ..................................... 30
FIGURE 20:ROOF INSTALLED SOLAR PANEL…………………………………………………………………..30
FIGURE 21: FABRICATED SOLAR STREETLIGHT BEING INSTALLED ........................................... 31
FIGURE 22: ASSEMBLING AND INSTALLING OF A SOLAR STREET LIGHT .................................... 33
FIGURE 23: CROSS - SECTION OF FABRICATION OF THE SOLAR STREETLIGHT ............................. 34
FIGURE 24: A TYPICAL 200AH BATTERY……………………………………………………………………..35
FIGURE 25: BATTERY CONNECTION…………………………………………………………………………….36
FIGURE 26: AN HYDROMETER…………………………………………………………………………….... ...39
FIGURE 27: INNER VIEW OF AN HYDROMETER ................................................................. 40
FIGURE 28: BATTERY TESTING DEVICE……………………………………………………………………… …41
FIGURE 29: A FABRICATED BATTERY RACK…………………………………………………………………..41
LIST OF TABLES
TABLE 1: WIRE SWG AND CURRENT RATING .................................................................. 20
TABLE 2: SETTINGS DONE ON THE FINISHED PRODUCT ....................................................... 27
TABLE 3: VARIOUS APPLICATION OF BATTERY.................................................................. 38
7|Page
CHAPTER ONE
1.0
GENERAL INTRODUCTION
1.1
ABOUT INDUSTRIAL TRAINING FUND (ITF)
The Industrial Training Fund (ITF) was established in the year 1971 under Decree 47 of 8th
October 1971. The provision of the decree empowers the ITF to promote and encourage the
acquisition of skills in industry and commerce with a view to generating a pool of indigenous
trained manpower sufficient to meet the needs of the Nigerian economy.
The main purpose of the ITF services is to stimulate human performance, improve
productivity, and induce value-added production in industry and commerce. The Fund through its
SIWES, Vocational and Apprentice training programs, also builds capacity for graduates and youth
self-employment, in the context of small scale industrialization, in the economy.
1.2
ABOUT STUDENT INDUSTRIAL WORK EXPERIENCE (SIWES)
The Student Industrial Work Experience (SIWES) was established by the ITF in 1973. The
scheme was established to solve the problem of poor practical skills preparatory for employment in
industries by Nigerian graduates of tertiary institutions.
The scheme was designed to give undergraduates the skills needed to cope in the labour
market after graduation and designed for duration of 4 months for Polytechnics and Colleges of
Education students and 6 months for University students. During this period, students are expected
to acquire all necessary practical skill, together with theoretical knowledge gained from their
respective institutions and put them into field practice to solve real life problems.
In addition, the scheme also gives students the basis of technological advancement and
development of Engineering in the economy. Participation in the SIWES program has become a
necessary pre-requisite for the award of Diploma and Degree certificates in specific disciplines in
most institutions of higher learning in the country, in accordance with the Education policy of the
government.
1.2.1
OBJECTIVE OF SIWES
Some of the objectives of the scheme are listed below:
 It exposes students to industry based skills needed for smooth transition from the
classroom to work environment.
8|Page
 It enables students of tertiary institutions to be exposed to the needed experience in
handling equipment and machinery that are not available in schools.
 It gives firms the avenue to assess the quality of graduates of tertiary institutions both
practically and theoretically.
 The scheme helps the students in building their communication skills with staffs at work
and in human inter-relationship.
 It exposes students to work ethics in their chosen profession.
 It gives students the opportunity to implement practical ideas gained from laboratories
in institutions to solve real life problems.
1.3.0 COMPANY PROFILE
1.3.1 MAGZONIK INVERTER AND SOLAR CO. LIMITED
Magzonik inverter and solar co. Limited is a company envisioned towards providing renewable
energy system which includes solar integrated inverter, solar street light and general domestic
installation.
These services include:
 Production of uninterrupted power system(INVERTER)
 Production of solar streetlight
 Electrical domestic wiring
 Consultation on Renewable energy system
 Product development
 General electrical installation
1.3.2 SOME OF THE OBJECTIVES OF THE COMPANY
 One of the major objectives of the company is to provide a reliable renewable power
system
 They also serve as a great source of employment for both skilled and unskilled workers
 They also develop product the speaks well of great convenient to the general public
9|Page
1.3.3 ORGANIZATIONAL CHART
Figure 1:Organizational Chart of Magzonik inverter and solar co.
10 | P a g e
CHAPTER TWO
2.0
AREAS OF EXPERIENCE
During the course of my industrial training I was involved, taught and exposed to the process
entails in the production of an inverter which include winding of transformer, building of different
circuitry, assembling, fabrication of the packaging casing etc. I was also taught how to handle the
different machines use in the fabrication of an inverter casing which includes drilling machine,
cutting machine, hacksaw, jig-saw, welding machine etc.
2.1
POWER INVERTER
Figure 2: picture of the company produced inverter
A power inverter, or inverter, is an electronic device or circuitry that convert direct current (DC) to
alternating current (AC). The input voltage, output voltage and frequency, and overall power
handling depend on the design of the specific device or circuitry. The inverter does not produce any
power; the power is provided from the DC source. A power inverter is entirely electronic circuitry.
Circuitry that performs the opposite function, converting AC to DC, which in turns charge the
battery is called a rectifier. The inverter made by the company invert in other to produce power and
11 | P a g e
also rectify in other to charge the battery. A typical power inverter device or circuit requires a
relatively stable DC power source capable of supplying enough current in ampere-hour for the
intended power demands of the system. The input voltage depends on the design and purpose of
the inverter. Examples include: 12 V DC, for smaller consumer and commercial inverters that
typically run from a rechargeable 12 V lead acid battery or automotive electrical outlet. 24V DC,
36V DC and 48 V DC, which are common standards for home energy systems that I worked with.
The following are the designs specifications
 OUTPUT WAVEFORM
The two dominant commercialized waveform types of inverters are modified sine wave and
sine wave. There are two basic designs for producing household plug-in voltage from a lowervoltage DC source, the first of which uses a switching boost converter to produce a higher-voltage
DC and then converts to AC. The second method converts DC to AC at battery level and uses a low
frequency transformer to create the output voltage, the second method was the one used in our
production
Figure 3:picture of different output waveform
o SINE WAVE:
A power inverter device which produces a multiple step sinusoidal AC waveform is referred
to as a sine wave inverter. To more clearly distinguish the inverters with outputs of much less
distortion than the modified sine wave (three step) inverter designs, where power inverter devices
12 | P a g e
substitute for standard line power, a sine wave output is desirable because many electrical products
are engineered to work best with a sine wave AC power source. The standard electric utility
provides a sine wave, typically with minor imperfections but sometimes with significant distortion.
Sine wave inverters with more than three steps in the wave output are more complex and have
significantly higher cost than a modified sine wave, Switch-mode power supply (SMPS) devices,
such as personal computers or DVD players, function on quality modified sine wave power. AC
motors directly operated on non-sinusoidal power may produce extra heat,
o MODIFIED SINE WAVE:
The modified sine wave output of such an inverter is the sum of two square waves one of
which is phase shifted 90 degrees relative to the other. The result is three level waveform with equal
intervals of zero volts; peak positive volts; zero volts; peak negative volts and then zero volts. This
sequence is repeated. The resultant wave very roughly resembles the shape of a sine wave. Most
inexpensive consumer power inverters produce a modified sine wave rather than a pure sine wave.
The waveform in commercially available modified-sine-wave inverters resembles a square wave
but with a pause during the polarity reversal. When operating induction motors, voltage harmonics
are usually not of concern; however, harmonic distortion in the current waveform introduces
additional heating. Numerous items of electric equipment will operate quite well on modified sine
wave power inverter devices, especially loads that are resistive in nature such as traditional
incandescent light bulbs. Items with a switch-mode power supply operate almost entirely without
problems, but if the item has a mains transformer, this can overheat depending on how marginally
it is rated. However, the inductive loads may operate less efficiently owing to the harmonics
associated with a modified sine wave and produce a humming noise during operation.
 OUTPUT FREQUENCY
The AC output frequency of a power inverter device is usually the same as standard power line
frequency, 50 hertz
 OUTPUT VOLTAGE
The AC output voltage of a power inverter is often regulated to be the same as the grid line voltage,
typically 220 VAC at the distribution level, even when there are changes in the load that the inverter
is driving. This allows the inverter to power numerous devices designed for standard line power.
 OUTPUT POWER
13 | P a g e
A power inverter will often have an overall power rating expressed in voltage ampere{VA} or kilo
voltage ampere {KVA} This describes the power that will be available to the device the inverter is
driving and, indirectly, the power that will be needed from the DC source.
 BATTERIES
The runtime of an inverter powered by batteries is dependent on the battery power and the amount
of power being drawn from the inverter at a given time. As the amount of equipment using the
inverter increases, the runtime will decrease. In order to prolong the runtime of an inverter,
additional batteries can be added to the inverter. When attempting to add more batteries to an
inverter, there are two basic options for installation: this will be further discuss
2.2
INVERTER PRODUCTION
Figure 4: Functional Block diagram of a typical power inverter
During my training I learnt that the inverter consists basically the following
1. The transformer
2. The oscillator
3. The current driver / rectifier unit
4. The control unit
5. The packed case
14 | P a g e
2.2.1
THE TRANSFORMER
Transformer is an inductively coupled circuit used for transmitting alternating
current energy, it is used in power electronics applications normally serve to provide isolation from
the input mains and to reduce voltage stress on switching components by more closely matching
the operating voltage to the switch voltage ratings, during my industrial training, the center-tapped
transformer (usually called two anode transformer) was used for modified sine wave inverter
configuration, which is common in our production due to it cheap and non-complex setup. The
center-tapped transformer used in powering the inverter serves as a step-up transformer. The
number of turns on the primary winding is different from that of Secondary winding. The primary
and secondary windings of conventional transformer for electronic application are wound on
tubular bobbin usually called former (insulated spool that serves as a support for the coil) made of
plastic or fiber material. The wound bobbins(former) are then enclosed by iron or steel cores in the
shape of figure start of “E” and “I” shaped laminated metal sheets, assembled through and round
the wound bobbins. The laminations are then clamped down to form a rigid assembly; the
transformers have insulator paper shrouds to insulate the windings from each other and from the
core. Both primary and secondary windings are wound on the same bobbin.
2.2.2
TRANSFORMER DESIGN CORE
Figure 5: transformer core construction type
15 | P a g e
The two most common and basic designs of transformer construction are the Closed-core
Transformer and the Shell-core Transformer. In the “closed-core” type (core form) transformer, the
primary and secondary windings are wound outside and surround the core ring. In the “shell type”
(shell form) transformer, the primary and secondary windings pass inside the steel magnetic circuit
(core) which forms a shell around the windings as shown below.
During my training the shell-type construction was the one use in winding the inverter
transformer. Shell type transformer cores overcome leakage flux as both the primary and secondary
windings are wound on the same center leg or limb which has twice the cross-sectional area of the
two outer limbs. The advantage here is that the magnetic flux has two closed magnetic paths to flow
around external to the coils on both left and right hand sides before returning back to the central
coils. This means that the magnetic flux circulating around the outer limbs of this type of
transformer construction is equal to Φ/2. As the magnetic flux has a closed path around the coils,
this has the advantage of decreasing core losses and increasing overall efficiency.
Figure 6: different laminations size
Figure 7: pictorial of the arranged E & I lamina
16 | P a g e
Figure 8:center-tapped transformer
2.2.3
Figure 9:completely wound transformer
TRANSFORMER WINDING PROCESS
A transformer works on AC signals; it cannot work on DC signals, as a DC signal does not
generate mutual inductance. A transformer consists of two coils, which are wound each on
laminated core. It is made up of primary and secondary sides respectively. There are two types of
coils; these are:
- Primary coil and
- Secondary coil.
The coil to which the AC supply is applied is called the primary coil/winding. The coil in
which Electromagnetic field (EMF) is induced and the output is taken is called secondary
coil/winding. The secondary coil can have one or more windings. In the transformer, electric energy
is transferred from one circuit to another circuit. During this transfer, the current and the voltage
can be changed, that is they can be increased or reduced. There is no direct electrical connection
between the primary and the secondary coil in a transformer. When AC current flows in the primary
coil, there is change in the magnetic flux generated in the primary coil with induced EMF which is
transferred to the secondary coil. The voltage generated in the secondary coil depends on the ratio
between the number of turns in the primary coil and number of turns in the secondary coil.
2.2.4
CALCULATION USED IN DESIGNING POWER INVERTER TRANSFORMER
In a transformer, the relationship between voltage, current and number of turns in the coils
is given by: -
=
=
17 | P a g e
Where:
 V1 is the input voltage to the primary
 V2 is the output voltage from the secondary
 N1 is the number of turns in the primary coil
 N2 is the number of turns in the secondary coil
 I1 is the current in the primary coil
 I2 is the current in the secondary coil
Taking a 2KVA 12V-0-12V center-tapped inverter transformer as a case study for my write up,
the following are put into consideration: Taking the magnetic flux density to be 1.4Tesla (assumed value) constant of proportionality (K) =
1.0,
The power Rating for the Inverter transformer (KVA) =2.0KVA, E2=12V
Assuming the efficiency of transformer =80%
Then Input rating =output /Efficiency=2000VA×0.80=1600VA (this value will also be used to
determine the number of mosfet for the current driver unit)
2.2.4.1
DESIGN OF CORES:
(a)Voltage per turn Et =k
(
)
Where S = Output KVA (2.0kVA)
Choosing K=1, for shell type single phase transformer
Et= 1.414Volts per turn
18 | P a g e
(b) Net Core Area Ai=
=4,549.5mm2
.
(c) Magnetic Flux Ф =BmAi = 1.4×4.5495×10-3 = 6.3693×10-3Wb
Ai= 0.9Ag (stacking factor = 0.9) ,Ag =
Stack height =
=
.
.
= 5,055
= 94mm2
(f) Lamination pieces (n) =
For a thickness of 0.5, n = 188 laminations
2.2.4.2
DESIGN OF COIL
(a) Number of turns:
Primary turns N1 =
=
= 9 turns (7) this will be double because the transformer is center-
.
tapped
Secondary turns N2 =
=
.
= 155.6 turns (8)
Since the winding is wound twice on the primary side for both halves of the switching period,
the total primary winding will be N1= 18 turns
Total number of turns = 18+155.6 = 173 turns
(b) Winding calculations:
Primary Current I1 =
Secondary Current I2 =
=
kva rating
input voltage
= 166.7A
=
=9.09
19 | P a g e
The table below is used to choose the conductor size of the coil using the ampere of the individual
winding
CONDUCTOR
INSULATO
ELECTRICAL
PERMISSIBLE
PACKIN
R
CHARACTERISTI
CAPACITY@200
G
C
C
AW
INSULATO
REALST. MAX
AMPERE
MT/COIL
DIAMETE
R
(ohm/km)
R
THICK
(mm)
(mm)
24
0.61
0.55
97.60
5.00
100
23
0.69
0.55
93.33
6.99
100
22
0.78
0.55
88.60
8.73
100
21
0.84
0.55
70.50
10.99
100
20
0.92
0.55
62.50
13.,87
100
19
1.09
0.55
51.70
18.00
100
18
1.19
0.55
39.50
22.00
100
17
1.33
0.55
3.90
28.00
100
16
1.53
0.8
24.40
35.00
100
15
1.60
0.8
20.02
42.00
100
14
1.69
0.9
15.60
55.60
100
13
1.72
0.95
12.50
65.00
100
12
1.78
1.00
9.80
88.40
100
11
2.06
1.00
7.38
100.60
100
10
2.48
1.00
6.30
140.60
100
8
3.01
1.50
4.20
200.00
100
G
Table 1: wire SWG and current rating
20 | P a g e
The table above is being followed when considering the maximum burst current for a short period
of time, the table is also helpful when testing a transformer that is the secondary winding of the
transformer has a higher resistance, more number of turns and it wire gauge is smaller whereas
the primary winding of the transformer has a lower resistance, few number of turns and it wire
gauge is bigger because the current drawn from the battery is higher
2.2.5
MAKING OF BOBBIN/FORMER
Figure 10: completely glued together fiber bobbin
The bobbin is a piece on which the copper coils are wound, it is usually made of plastic. During my
training the bobbin is made from a recyclable fiber material which is sources from an ice block
machine factory within the industrial park, the E shaped lamina is used to measure the required
shapes on the fiber material, the shapes are cut using a jig-saw. the shapes are then glued together
which form the bobbin as show above.
2.2.6 WINDING OF THE COPPER COIL
Figure 11:completely wound transformer without lamination and a copper coil
21 | P a g e
The copper coil is manually tensioned and wound round the bobbin/former, a liquid varnish (chilak)
is poured into the wound coil to make it stick together and also help to filled air space that cause
vibration when the transformer is loaded, thereafter the two coil are separate with an insulator paper
The iron sheet laminations are then arranged into the wound bobbin
2.2.7 TESTING OF THE WOUND TRANSFORMER
The following are checked when testing a wound transformer
1.
Winding Resistance: Winding resistance can be represented by the resistances of the copper coil used in the
windings, R1 and R2 for primary and secondary, respectively. This can be tested using the
ohmmeter on the digital multimeter.
2.
Winding voltage: The transformer’s secondary terminal is connected to a 220VAC and the output voltage at
the primary terminal is measured using a voltage meter, this will give a 12VAC range for a 12volt
inverter ,24volt range for a 24volt inverter and 48volt range for a 48volt inverter, this depends on
the size of the lamination and copper coil that was used
2.3
THE OSCILLATOR AND DRIVER UNIT
Figure 12:assembled oscillator and driver unit
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The oscillator and driver unit are assembly on a ready-made printed circuit board. The components
datasheet plays an important role in identifying the various component that can be use and their
characteristics The oscillator uses an SG3524 with other component to generate the 50Hz
frequency required to generate AC supply by the inverter.
2.3.1 DRIVER SECTION
Mosfet drive signal from pins of the SG3524 are coupled to base of transistors. This result in the
separation of the signal into two different channels and an amplification of the signal to a sufficient
output level from the transistors collector. The resulting MOSFET drive signal at collector is
coupled to the gate of each MOSFET in the first and second MOSFET channels respectively. The
driver section made up of the MOSFETS AND RESISTORS are incorporated with the oscillator
on the printed circuit board . Heat sinks are attached to the back of the of the driver unit
Figure 13: printed circuit board
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The capacity of an inverter is a function of:
 The type and number of power MOSFETs used
 The size and capacity of the power transformer used for AC Power Supply
The driver unit configuration consists of an array of MOSFETs connected in parallel. The MOSFET
commonly used by the company in the driver design has its path number as IRFP260N, IRFP250.
the following datasheet parameters is for IFRP250:
- Current rating = 39A
- Voltage rating = 100V
- Power factor (pF) = 0.75
- Power rating = 190W
The Total number of MOSFET is given by:
Number of MOSFETSs = Actual Power of the design/ Power rating of the MOSFET:
That is; 1500/190 = 7.89 Hence, 8 MOSFETs were used; with 4 on each parallel channel, boosting
the current to drive the transformer.
Figure 14: data sheet of a Mosfet
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2.4
INVERTER AUTOMATIC TRANSFER SWITCH (CONTROL UNIT)
the control unit function as the medium or controller that tells the inverter what to do at a
point in time. The control unit consist of the following circuitry for
1. Low battery
2. Overload
3. Mains detector
4. Automatic change over.
2.5
PRODUCTION OF PACKING CASING
Packaging of the constructed product was done to achieve a good looking and presentable
product. During the packaging, some factors were considered; these include: -The durability of the
material to be used in the packaging, materials like wood, plastic or metal could be used but for this
product, metal sheet was used; this is to ensure easy dissipation of heat to the environment. The
ventilation of the package was also considered; this is to help in control of the temperature of the
system since most of the components in the construction are heat-generating components.
The packaging process involved fabrication of the casing using a metal steel plate in case
of a 2KVA inverter, angle bar and metal steel plate in case of other KVA’s
2.5.1 PRIMING
Priming is the process of covering the raw metal plate or angle bar with raw glossy paint
Figure 15: priming of casing
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2.5.2 BASE SMOOTHING
Base smoothing is the process of smoothing the surface of the primed metal work, this is done by
using a silicone paper and water.
This make the surface to be smoothed before laying the auto base paint
2.5.3
AUTOBASE PAINTING
Figure 16:autobase painted casing
Material used for autobase painting
1. Autobase Paint
2. Hardener
3. Slow Thinner
4. Thinner
5. Spirit
6. Oil
7. Shiner (silver colour)
Priming, base smoothing and autobase painting are the procedures followed to prevent the metal
casing from rusting and also to beautify the end product and labeling of the required information
After finish assembling of the product the following setting are done on the inverter
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Inverter output voltage
220volts
Inverter frequency
50Hz
Minimum battery voltage
10.0volts
Minimum A.C. input voltage
180V
Maximum A.C. input voltage
250V-
Table 2: settings done on the finished product
2.6
INSTALLATION PROCESS
 the batteries were arranged into the battery rack and connected in series and parallel as
required for the inverter system
 the inverter is then place on the battery rack, connect to the battery and it is powered on
for testing and off immediately
 the charge controller is installed close to the battery, as directed by the manufacturer
 output of the battery and the output from the solar panel are then connected to the controller
consequentively
 all the connection is properly checked and tested using multimeter
 trunking system of wiring are majorly been used during installation expect for exceptional
cases where conduit system of wiring has already been laid
 the load to be powered be the inverter are isolated from the distribution board are
connected to the output of the inverter
 Lastly, the system is then powered on and loaded
2.7
MAINTENANCE, SAFETY AND PRECAUTION
The following maintenance practices and safety precautions are followed to improve the life span
of the system and prevent hazards to the users.






1. Dead batteries should not be used with the inverter
2. The battery terminals should not be removed too often. When it is removed, replacement
of correct polarity must be ensured.
3. The inverter must be put in a moderate temperature environment.
4. The inverter should always be shut down when not in use
5. The inverter should always be partially loaded (not more than 80% of its maximum
capacity will be enough).
 6. The input plug of the inverter should be plugged to a three-pin, properly earthed socket
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2.8
SOLAR PANELS, INSTALLATION AND SOLAR STREET LIGHT
2.9
SOLAR PANEL
Figure 17:solar panel under test condition
Solar systems are an environmentally friendly way of producing electricity for domestic usage, the
technology relies on photovoltaics (PV) cells to turn sunlight into electricity
2.9.1 Types of solar panel
1. Mono-crystalline: - mono crystalline are solar panel that is made entirely of a single crystal
structure, it is usually made of silicon which are form into bars and are cut into wafer. It is
usually dark in colour
2. Poly-crystalline: - poly crystalline is produced by making use of a crystal of silicon
manufactured by melting many fragment of silicon and other material together to form the
wafers for the solar panel example of material used are: - copper indium gallium
selenide(CGIS). It is blueish in colour
Figure 18:different types of solar panel
Three (2) common connections type of photo voltaic system design
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1. The system is connected to the utility grids and has battery storage to provide the power
need for consumption.
2. The system is connected to a battery storage to provide emergency power back up.
Solar panel installation accessories include
1. Aluminium solar rack
2. Bot and nut
3. Nail
4. Connecting wires
5. Binding wire
2.9.2 IMPORTANT FACTOR CONSIDERED WHEN INSTALLING SOLAR PANEL
The following factor are considered before installing a solar panel are as follows
1. Location: - when installing the solar panel, it must not face the direction of either sunrise
or sunset, in order to achieve an optimized energy, form the solar panel, therefore the solar
panel must face the direction of the sun path
2. Seasons: - solar panels receive more direct ultra-violet ray of the sunlight during the
summer (dry season) than in the rainy season even though the panel was often set to the
latitude of an angle equal to the latitude
3. Climate: - solar arrays are most efficient in the brightest day. Direct sunlight efficiency can
dramatically be reducing if the sky is overcast
4. Obstacle or shade: - anything that blocks the sunlight from falling on the solar panel will
reduce the efficiency of the array, which include shadows from nearest building, tree
branches, leaves, dust and other debris
2.9.3 INSTALLATION OF SOLAR PANEL
The azimuth angle of the square solar cells is the angle of south direction and Vertical plane of the
square, which is the direction during installation of the solar panels. In general, efficiency of the
solar cell is highest when the square faces south (i.e. azimuth angle of 0 °). The declining angle is
the angle between the surface of the solar cell and the horizontal plane which is the best declining
angle that the square can make the maximum generating capacity per year. The optimum declining
angle is related to the local latitude and with the raise of the latitude, the inclination will also
increase.
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.
Figure 19: picture showing best positioning of solar panel
Two ways in which solar panel is been installed
1. Rooftop installation: - this is the type of installation whereby the solar panel is been
installed on the roof of a building, installing mounting rack or angle bar iron are used to nail
the panel to the roof in other to prevent the solar panel from damages from the wind. During
my training, this was the major mode of solar panel installation that I was vividly involved
in
Figure 20:roof installed solar panel
2. Ground mount or standalone installation: -this is the type of installation whereby the
panel is being installed on a special made and design shed, here the installing rack are going
to be in a conjoining ways which is going to be capable of carrying heavy load
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2.10.1 SOLAR POWERED STREET LIGHT
Figure 21: fabricated solar streetlight being installed
2.10.2 PRODUCTION OF SOLAR STREET LIGHT
The solar street light does not need to set up the transmission line or route the cable and no
any special management and control are required. It can be installed in the entire public place such
as the square, the parking lot, the campus, the street or the highway etc.
According to principle of photovoltaic effect, the solar panels receive solar radiation during
the day time and then convert it into electrical energy through the charge and discharge controller,
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which is finally stored in the battery. When the light intensity reduced to about 10 lx during night
and open circuit voltage of the solar panels reaches at a certain value, the controller has detected
voltage value and then act, the Battery offer the energy to the LED light to drive the LED. the LED
emits visible light at a certain direction. Battery discharges after certain time passes, the charge and
discharge controller will act again to end the discharging of the battery in order to prepare next
charging or discharging again A good LED street lighting system is characterized with high
efficiency, energy-saving, long-life, high color rendering index and environmental protection,
which not only has a great significance on energy-saving of the city lighting
The following basic requirements on a qualified solar LED street light system shall meet during
design process:
(1) Learn general information of the meteorological conditions in the area.
(2) Select the cost-effective solar panel, the controller, the battery and a series of components.
(3) Adopt effective measures to protect the system.
The system consists of:
(1) Solar panel
(2) LED lamps
(3) Light pole
(4) Control box (charger controller, battery
(5) wires and cables
2.10.3 CHARGE CONTROLLER
The charge controller is the intelligent core of the whole solar streetlight system and inverter
system, in the street light system the charge controller controls the entire system's normal operation
and automatically prevents the battery's overcharge, or over discharge. Its basic functions must also
have light control, time control and anti-reverse connection etc. The controller generally has a
simple measurement function.
Automatic switch of lamp
The LED lights automatically turn on in the evening and automatically turns off power
supply at dawn or certain time, this is the time control function of the controller. It should be noted
that: In the evening and dawn, the ambient light changes slowly, the brightness still varies during
this process. In general, we can add a delay circuit (A few minutes) in the light control circuit. Thus,
when the lights turn on or turn off, there will be no flicker phenomenon.
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During design of the controller, such as Load Terminal Short-circuit Protection, AntiLightning Protection, Battery Reverse Polarity Protection and other technical requirements are
also necessary selection of the solar street light battery
Figure 22: assembling and installing of a solar street light
2.10.4 MOLDING OF THE BASEMENT FOR THE STREETLIGHT POLES
Our casting operation was built by masonry under our supervision to certify the basic survey
requirements were met. 1 Bags gravel, 3 bags of sand and 1 bags of cement were mixed together
and our pole was erected in the paste and plumed to obtain a 90oC vertical angle from the ground.
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Figure 23: cross - section of fabrication of the solar streetlight
2.10.5 INSTALLATION OF THE SOLAR POWERED STREET LIGHT
The solar street light is installed on the dry molded basement guided with a rope and are bolted
down on the molded concrete which can either be made on site or pre-cast at the company work
shop
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2.11
STORAGE (BATTERIES)
Figure 24: A typical 200Ah battery
It is a direct current power source to electrical or electronic equipment or devices that make
use of it. Battery is being made available as direct source of energy. It is therefore necessary to
select a reliable battery for optimum performance
2.11.1 TYPES OF BATTERIES
2.11.2 VRLA: - technology VRLA stands for Valve Regulated Lead Acid, which means that
the batteries are sealed. Gas will escape through the safety valves only in case of overcharging or
cell failure. VRLA batteries are maintenance free for life.
1. Sealed (VRLA) AGM Batteries AGM stands for Absorbent Glass Mat.
2. Sealed (VRLA) Gel Batteries Here the electrolyte is immobilized as gel. Gel batteries in general
have a longer service life and better cycle capacity than AGM batteries. VRLA batteries can
therefore be stored for up to a year without recharging, if kept under cool conditions.
2.11.3 FLOODED BATTERIES (air vented)
2.11.4
ADVANTAGES OF FLOODED BATTERIES
 initial cost that are easy is considerable
 water or electrolyte can be manually added when required
 good for high current application
 excellent tolerant of improper recharge voltages
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 easy replacement
 some of the available designs are even good for deep cycle application
 excellent for working at extreme cold weather condition
2.11.5 VARIOUS CONNECTION OF BATTERIES
The runtime of an inverter powered by batteries is dependent on the battery power and the amount
of power being drawn from the inverter at a given time. As the amount of equipment using the
inverter increases, the runtime will decrease. In order to prolong the runtime of an inverter,
additional batteries can be added to the inverter. When attempting to add more batteries to an
inverter, there are three basic options for installation:
Figure 25: battery connection
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Three (3) major ways in which batteries are connected are: 1) SERIES CONNECTIONS: - this is the type of connection in which the configuration of the
battery is added up in the end to end (positive terminal to negative terminal), Series
configuration If the goal is to increase the overall voltage of the inverter,
2) PARALLEL CONNECTIONS: - this is the type of connection in which the configuration of
the battery is added up in the linear end to end (positive terminal to positive terminal and
negative terminal to negative terminal) parallel configuration If the goal is to increase the
overall ampere hour of the inverter
3) INTER SERIES AND PARALLEL CONNECTION: - this is the type of connection in
which the configuration of the batteries is inter woven between series and parallel connection,
this configuration is made to either increase voltage and current
2.11.6
VARIOUS APPLICATION OF BATTERY
Batteries are made for different application
CYCLE USAGE: when a battery is being used as a power source on a regular basis and it is being
discharge and subsequently recharged the battery is considered to be in a cyclic use, this
determining factor in the life of this battery is the number of charge and discharge cycles that can
be completed. In t cyclical application of battery up to 1,000 charge and discharge cycle can be
expected depending on the average depth of discharge (DOD)
STANDBY USAGE: standby usage is meant to act as an emergency power source where the main
power source has failed due to some reason. consequently, standby batteries are always keep fully
charge so that they can serve as reserve. In standby use of battery, the battery is expected to last
longer than a cycle use battery, during my training, most of the inverter installation I was involved
in are either based on cyclic usage or standby usage, depending on the client, also all cyclic usage
is integrated with solar based system, which help to compensate the inverter system during the day
time
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The Table Below Shows Various Application of Battery
Standby use
Cycle use
Emergency light and the guide light Cable television
Uninterrupted power supply( ups)
Portable measuring instruments
Computer peripheral terminal
Power tools
Marine equipment
Electrical powered bicycle
Solar power system
Medical equipment
Security and alarm system
Garden lighting
Telecommunication systems
Off grid inverter system
Table 3: various application of battery
2.11.7
REVIVING OF FLOODED BATTERIES
During my industrial training I was introduced to how to revive the flooded battery
popularly called wet cell battery using simple and easy to do method.
2.11.8
HYDROMETER
A hydrometer is an instrument used to measure the specific gravity or relative
density of liquids, that is, the ratio of the density of the liquid to the density of water
Hydrometer is usually made of a sealed hollow glass tube and consist of a cylindrical stem and a
bulb weighted with a heavy material (lead or mercury) to make it float upright. liquid to be tested
is poured into a hydrometer cylinder or a plastic bowl and the hydrometer is gently lowered into
the liquid and the liquid is sucked into the hydrometer by squeezing the rubber ball at the top which
make the liquid to float freely.
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Figure 26: an hydrometer
The point at which the surface of the liquid touches the stem of the hydrometer correlates
to relative density and this point is used to determine or measure of its state of charge, this help to
test to quality of the sulphuric acid in a flooded
The hydrometer makes use of Archimedes principle: a solid suspended in a fluid is buoyed
by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid ,
the lower the density of the fluid ,the deeper a hydrometer of a given weight sinks the stem is
calibrated to give a numerical reading
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Figure 27: inner view of an hydrometer
2.11.9 PROCESS OF REVIVING A FLOODED BATTERY
 the battery voltage was first tested using the multimeter to determine it voltage
 the battery was then tested with a battery load tester to determine if it still have a cranking
ampere. Which is expected to high if the battery is still good and which is expected to be
low if the battery needs reviving.
 If the battery needs revive, the battery will be open up and the hydrometer will be used to
test its electrolyte state of charge and also this will help to determine if the battery cells are
still good
 The sulphuric acid(H2SO4) will be mixed one part to three part of distilled water, NOTE:
care must be taking during these period while handling the acid, the acid must be pour into
the water very slowly as large amount of heat will be generate when pouring the acid, also
the container used in mixing must be made of plastic, as metal will be corroded by the acid
 The diluted mixture must be left to cool for up to 12 hours, then the quality of the mixture
will be tester using the hydrometer which must be on the green label if the mixture is of
good quality
 The diluted mixture is poured into the battery cells one after the other and charged with a
very low amperage charging system
2.11.10
TESTING OF BATTERIES
Battery load tester is an electronic device used for testing the state of an electric battery, it is used
to determine the cranking ampere of the battery to be tested
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The battery to be tested must be well charge and left for up to 12hrs before using a battery load
tester to test it, the battery load tester work by powering a heating element in the tester, this drawn
a lot of ampere from the battery, these depend on the rating of the battery load tester and the testing
period must not be more be than 60 seconds
Figure 28: battery testing device
2.11.11
BATTERY RACK
A battery rack is a housing that is used to arrange batteries adequately for storage
Figure 29: A fabricated battery rack
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CHAPTER THREE
3.0
CHALLENGES/PROBLEMS ENCOUNTERED AND THEIR SOLUTIONS
During the first quarter of my industrial training, the following challenges were
encounter
o HANDLING OF WORK TOOLS:
I found it difficult to handle some of the machines used in fabrication
process, due to vibration and directional motion of the machines.
o SOLDERING:
soldering is a day to day activity in the workshop, I handled some of the
soldering of the component to the printed circuit board, this made my soldering to
be rough and defective.
o BATTERIES
The net weight of a 200Ah batteries makes it difficult to be carried or moved
from one place to another especially during installation.
o HEIGHT
During the installation of solar panels, some of the installation were done at higher
height to the ground level, this bring about the use of safety devices such as safety belt and
ropes
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CHAPTER FOUR
4.0
APPRAISAL, RELEVANCE TO EEE DISCIPLINE, & CONCLUSION
4.1
APPRAISAL AND CONCLUSION: My experience during the period of industrial attachment has been an enriching and
innovative one. The SIWES scheme is indeed an innovative concept and looking back I am glad
that worked at “MAGZONIK INVERTER/SOLAR CO. LTD”. The experiences have been far
rewarding and the report summarizes the details. From the full details on the experience which I
had during the training program which gave me the privilege to relate with senior professionals and
other students from different institutions. The knowledge acquired is not only academic or technical
skill as the case may be, I was also made to understand the importance of other fields of study and
ultimately appreciate the roles they play to the success of any industry. The experience makes me
appreciate the nature, benefits and intricacies of my chosen field of study both in the classroom and
in the larger society
The program increases the potentials of a student at the same time helps me to adapt a
disciplined attitude that will guide me after school when offered an opportunity to put to practice
what I had gotten all through my stay in the University. It gives University students the opportunity
to put into practice what they have been learning theoretically all through their stay in school. It
exposes the student to a working environment experience and acts as a guide to the student when
he or she finally graduates and goes into the business industry to start up working. Students should
know what aspect of their course they want to specialize. Either they want to go into Electrical,
Telecommunications, Electronics, Manufacturing. etc. This will act as a guide to the student to
know what company to seek placement. Students should take maximum use of the opportunity
given to them to learn and make use of the resources at their disposals and not just be bench warmers
in their organization.
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4.2
RECOMMENDATION:
In view of my experience during my industrial training, the following recommendations
are made to the students, university, industrial training fund (I.T.F) and the companies:
 Students should personally ensure that they get a good placement for the program in time
to commence and gain the best from the six-months.
 Students should make sure that the entire period for the attachment is completed before
bowing out of the program.
 Also, student should have a focused mind and interest as it will help them get the maximum
knowledge attainable from the company attached to.
 Not all students have the opportunity of getting good industrial training placement, so the
university should ensure they establish good relationships with companies, firms and
organizations capable of assisting in the SIWES program on a yearly basis thereby helping
the less privileged students.
 On the part of I.T.F, Student supervision should also be intensified to make the program
more effective.
 The firms should ensure that a well-structured program for the period of training is spelt out
and be seriously adhered to, so that students can benefit.
 Also, the firms should see their role in the program as one of contributing to the nation’s
educational system and not as a means of exploiting I.T students as cheap labor.
4.3 RELEVANCE TO EEE DISCIPLINE:
The relevance of the experience gained can be linked to the following courses:
o Electrical service design
o Renewable energy
o Power electronics
o Electromagnetic field and waves
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4.3
REFERENCES:
 www.wikipedia.com/power inverter
 www.brighthubengineering.com/diy-electronics-devices/96783-designing-your-owntransformer/
 Magzonik inverter manual
 Forrest, M. (2000). Getting Started in Electronics (2nd Edition).
 www.datasheetcatalog .com
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