Uploaded by Kazeem faruk


(Oke Balogun, Epe, Lagos State.)
MATRIC NO: 170221025
This report is dedicated to the Almighty God my creator, strong pillar and source of inspiration,
wisdom, knowledge and understanding.
I would like to express my special thanks of gratitude to my boss at the place of SWEP
placement, Mr. KUNLE for his able guidance, sincere support and corrections in completing my
I would also like to extend my gratitude to all the academic and non-academic staffs for their
assistance and support during the SWEP period.
Title Page
Table of Contents
Chapter One
About SWEP
Scope of SWEP
Aim and Objectives of SWEP
History and Background of the Company
Company Objectives and Scope of Service
Board of Director (if applicable)
Departments/Sections in the organization
Branches of the Company (if applicable)
Organizational Chart/Structure of the Company
Chapter Two
Engine generators and its modes of operation
Mode of operations
Sately precaution or rules and regulations of the company
Equipment, machines, tools, devices.
Chapter Three
Chapter Four
Summary of Attachment Activities
Challenges Encountered during the training
Personal Suggestions, Recommendations towards improvement of the SWEP in general
In this report, the writer has penned down a full review of his Students’ Work Experience
Program (SWEP) which was undertaken at Kunle Generator Repairs. The report contains details
of practical experiences gathered during the course of the program and theoretical principles on
which such practical experiences depend, gathered from both courses taught in the classroom
and personal research.
The report generally deals on generators which are electrical machines that convert mechanical
energy to electrical energy. However, a.c. generators which are fueled by gasoline (petrol) are
mostly dealt with as this is the area of specialization in the writer’s place of assignment. Some of
the things treated in the report include the evolution, working principles, and parts of a generator,
how to troubleshoot and repair these generators.
The report is organized as follows;
The introduction deals basically on general information on SWEP, my place of assignment, and
introduces the general experience gained during the course of the program.
In Chapter 1, Introduction.
Chapter 2 treats in details, engine generators and its modes of operation
Ch deals with the various systems and components of an a.c. (gasoline) generator.
The various faults in an a.c. generator, their causes and remedies are discussed in Chapter 3.
Also discussed in this chapter are troubleshooting and maintenance of a generator.
In Chapter 4, the various tools used to work on the generator are discussed.
Chapter 5 discusses the various practical skills learnt during the SWEP program.
Conclusions and recommendations were finally made in areas necessary for improvement of the
SWEP program in the future. A page for references has been included for further reading of
some issues discussed in this report. Care was taken to ensure that all that is written in this report
are accurate to the writer’s best understanding.
The Student Work Experience Programme (SWEP) is one designed to enable 300 level students
of the Faculty of Engineering, Lagos State University to acquire practical skills and experience at
the shop floor. It is part of the accepted practical skills training programme approved by the
National University Commission (NUC) as part of minimum academic requirement for the
award of degree in Engineering for Nigerian Universities.
The main objective of the programme is to bridge theory with practice by creating an avenue for
students to be exposed to real engineering jobs out there in the society and real time job
situations and environment. Another objective is that it prepares students for work situation they
will meet after graduation as well as expose students to work methods and various ways of
handling machinery and equipment which are not available in the school. This is to mention a
My Student Work Experince Programme (MEE 398) was done at Kunle Generator Repairs
located at Oke Balogun, Epe, Lagos State from the 12th day of July to the 12th day of August
2021 and it was done under the supervision of Mr. Kunle at Kunle Generator Repairs is a small
scale engineering firm
2.0 Introduction
An engine-generator (often referred to as just a generator) is one which comprise of both an
electrical generator and an engine (prime mover) mounted together to form a single piece of selfcontained equipment. The mostly used engine is piston engine but gas turbines are used
occasionally and there are even hybrid diesel-gas units, called dual-fuel units. Many different
forms of engine-generators are available - ranging from very small portable petrol-powered sets
to large turbine installations. The primary advantage of engine-generators is the ability to
independently supply electricity, and this allows the units to serve as backup power solutions.
This is the most popular kind of generator in Nigeria today and their kind would be the basis of
other analysis in this report.
2.1 Mode of Operation of a Typical Generator Engine
The needed shaft power for the alternator is supplied by the engine of the generator. The engine
comprises of the following; fuel tank, fuel pipes, carburetor (for small generator sets) or fuel
injectors (for large generator sets), cylinder, piston, connecting rods, engine block, connecting
gears and crankshaft. With small generator sets, fuel tanks are placed over the remaining
components of the generation compartment; while this may be otherwise in medium and larger
generator sets, such as placed either below or beside depending on how soonest and faster the
fuel is to reach the designated points.
In order to start a generator, set, you manually pull the starter handle to rotate the crankshaft for
small generators while in large generator set, you either apply the method above or press the
on/off button or by key-starter. Before doing this, this fuel tap must have being turned on to
allow fuel to run from the fuel tank into the carburetor where the fuel is mixed with air and the
mixture supplied to the combustion chamber in the cylinder. The rotation of the crankshaft about
its linear axis makes the piston move away from the cylinder.
Considering a gasoline operated engine, the spark plug is usually hung and fitted at the upper
housing of the cylinder in a gasoline piston-cylinder compartment and is charged through
capacitors. As gasoline fuel mixture reaches the cylinder compartment, sparks are introduced by
the spark plug. Generator engines operate in either of the following below;
AC generators (whether small, medium or large in size) comprise of various systems and
components and in other to understand the working and construction of these generators, there is
need to study the individual systems and components. This is the reason for this chapter.
The systems in an a.c. generator could either be mechanical or electrical and these systems
comprise of different components which work together to ensure the proper functioning of the
system. The various systems and their components are discussed below.
3.1 The Combustion System
The engine of a generator produces mechanical force and motion from the latent chemical
energy in the fuel burnt in its combustion chamber. Hence, it is called an internal combustion
engine. Various type of generator engines are designed to operate on different variety of fuels
such as diesel, gasoline, propane (in liquefied or gaseous form), or natural gas. Smaller engines
usually operate on gasoline while larger engines run on diesel, liquid propane, propane gas, or
natural gas. Some other engines can also operate on a dual feed of diesel and gas, kerosene and
gasoline in a bi-fuel operation mode.
The cycle employed in the engine of a generator could be four-stroke or two-stroke. There is one
power stroke for every four strokes of the piston movement (up-down-up-down) for a four-stroke
piston engine. The processes are intake stroke, compression stroke, combustion stroke and
exhaust stroke. During the intake stroke, combustible mixtures are placed in the combustion
chamber and these mixtures are placed under pressure in the compression stroke. While the
mixture is burnt with the hot mixture expanded and pressing on and moving parts of the engine
to perform useful work during the power stroke. Lastly, during the exhaust stroke, the cooled
combustion products are exhausted into the atmosphere.
Every typical two-stroke engine has one power stroke for every two strokes of the piston (updown). It is an internal combustion engine that completes the thermodynamic cycle in two
movements of the piston as compared to four movements for a four-stroke engine. Efficiency is
increased and is accomplished by using the beginning of the compression stroke and the end of
the combustion stroke to perform simultaneously the intake and exhaust functions.
Two-stroke engines are having different design types which vary according to the method of
introducing the charge to the cylinder, the method of scavenging the cylinder (exchanging burnt
exhaust for fresh mixture) and the method of exhausting the cylinder. Spark-ignition two-strokes
are small and light for their power output and mechanically very simple; however, they are also
generally less efficient and more polluting than their four-stroke counterparts.
The components of the combustion system for a four-stroke engine are discussed below:
Piston: This is usually situated in the cylinder of the cylinder block and its up-down movement
is enhanced by the ignition of the spark plug and the opening and closing of the valves. It has
grooves which houses its rings which are usually equal to or greater than 2 depending on the
design of generator). A piston ring is an open-ended ring that fits into a groove on the outer
circumference of a piston in a reciprocating engine and its main functions include;
A generator piston usually have 3 rings with the top two primarily meant for compression sealing
while also controlling oil and the lower ring for oil supply control to the liner which lubricates
the piston skirt and the compression rings (oil control rings).
Adequate supply of pressure in the combustion chamber is ensured by the piston rings. The
major problem encountered with use of piston is that carbon becomes deposited on the piston
head and its sides after being used for some time and it leads to low efficiency of generators. But
this can be fixed by removing the carbon or replacing the piston and piston rings as we always
did during my industrial training experience.
Piston with Rings, Basket Bearing, Connecting rods, and Key
Crankshaft: This component is usually forged from steel and it is the part of the engine which
translates the reciprocating linear piston motion into rotation. In order to do, the crankshaft has
"crank throws" (additional bearing surfaces whose axis is offset from that of the crank) to which
the "big ends" of the connecting rods from the cylinder attach. It typically connects to a flywheel,
to reduce the pulsation characteristic of the four-stroke cycle, and sometimes a vibration damper
at the opposite end thereby reducing the torsion vibrations often caused along the length of the
crankshaft by the cylinders farthest from the output end which acts on the tensional elasticity of
the metal.
The connecting rod of the crankshaft is held within the piston by a basket bearing. The
crankshaft is normally replaced when there is a problem with it as a result of bad ball bearing.]
Cylinder Block: This is the component that houses the combustion chamber and its component
parts include the cylinder- where the piston is housed, the inlet and exhaust valves, and the
cylinder cap- on which the spark plug is located.
Cylinder Block
Due to the heat from the combustion chamber, the cylinder block is shaped in a series of
radiating fins with a large area of metal to radiate heat away from the cylinder.
Governor: In gasoline generators, the governor regulates the amount of fuel admitted thereby
maintaining a near constant speed no matter the load or fuel supply condition. The governor can
usually be adjusted by turning a screw attached to the governor control. Hence, the output
voltage depends on the efficiency of the governor.
Fig. 3.4 Governor
Spark Plug: The spark plug is responsible for ignition in the combustion chamber of the
cylinder and as stated above, it is located on the cylinder cap. It causes the ignition of the air and
fuel mixture from the carburetor. The spark plug is present in any internal combustion engine
that makes use of fuel because its ignition enables piston movement. It should be noted that a
red-like spark or too bright spark is not usually suitable for ignition but a blue brownish-like
spark. The spark plug is replaced with a good one when bad.
Spark Plug
3.2 The Fuel Supply System
This system is one of the mechanical systems of a generator and comprises of two main
components-the fuel tank and the carburetor.
The Fuel Tank: The fuel tank houses the fuel (in this case, gasoline) for the engine. For small
and most medium size generator sets, the tank is usually located at the top with a hose
connecting its tap and the carburetor. The capacity of the tank vary with the size of the generator
starting from as little as 4 litres in the 950KVA generator which was the smallest gen-set we
worked on at the company. Some fuel tanks usually have a fuel gauge indicating how much fuel
is available at the time it‘s being checked.
Fuel tank and tap
Despite the fact that the fuel tanks usually come with filters, every of the tanks could sometimes
become dirty even though they come with filters and have their capacities reduced as a result of
water at the bottom of the tank. The dirts which accumulate at the bottom of the tank and the
water are usually transferred when an empty or partially full tank is being refilled and these
could gradually fill the tap and reduce the amount of fuel reaching the carburetor or even block
the tap entirely.
In order to resolve these problems, the tank is detached from the chassis so that the tap is
removed and the content of the tank is poured into a container. The water and dirt would be seen
at the bottom of the container. By so doing, the tank is flushed. The tap/sediment cap is also
cleaned and dried. The tap is fixed to the tank and then the unit is returned to the chassis.
Carburetor: The air and fuel mixture for combustion in the cylinder block is supplied in the
correct proportion by the carburetor. Some generators make use of one carburetor while others
use fuel injectors. The liquid fuel is atomized by the injector and the required amount of fuel
sprayed into the combustion chamber of the engine. The carburetor works on Bernoulli's
principle- the faster air moves, the lower its static pressure, and the higher its dynamic pressure.
The major parts of a carburetor include the fuel inlet, float pin, float chamber, float chamber
cover, hose and choke. When fuel flows into the float chamber cover of the carburetor, it gets
filled which causes it to push the float chamber up.
It exerts pressure on the float pin in the float chamber so that no more fuel comes into the float
chamber. The fuel evaporates through the fuel inlet to the cylinder block. When the pressure is
greatly reduced, the whole process is repeated. The choke of the carburetor plays a vital role in
starting the generator. When the engine does not start despite the starter being pulled, it is due to
the fact that fuel becomes less readily vaporizable. Hence, there is less fuel to air in the air and
fuel mixture supply to the cylinder. To provide the extra fuel, the choke is used. The choke is a
device that restricts the flow of air to the carburetor hereby enabling a rich air and fuel mixture
for ignition.
3.3 The Exhaust System
The incomplete combustion of carbonaceous fuel in the engine lead to pollution by the emission
of sulphur (IV) oxide, SO2, carbon (II) oxide, CO and so on. These air pollution emissions might
be fatal and exposure to the noise from the engine’s exhaust for a long time can lead to loss of
hearing. Therefore, the exhaust system must be installed in such a manner to prevent its
emissions from accumulating from the combustion chamber in the engine. The exhaust system
contains devices to control pollution, both chemical and noise pollution. In addition, for cyclic
combustion engines, the exhaust system is frequently tuned to improve emptying of the
combustion chamber. It is important to note that a generator must never be operated if it does not
have a full exhaust system.
Silencer: A silencer (Muffler) is a device for reducing the amount of noise emitted by the
exhaust of an internal combustion engine. Silencers are installed with the exhaust system of all
engine-generators although they not designed to serve any primary exhaust function. The
silencer is engineered as an acoustic sound proofing device designed to reduce the loudness of
the sound pressure created by the engine. This is done through destructive interference wherein
opposite sound waves cancel each other out. An unavoidable side effect of silencer use is an
increase of back pressure (resistance of a moving fluid) which decreases engine efficiency. This
is because the engine exhaust must share the same complex exit pathway built inside the
3.4 The Starter System
This system is part of the mechanical system of a generator and includes the following parts:
Starter: The starter has a small catcher, big catcher, washer, coiling spring, starter rope, starter
handle (with all made of plastic). Without this component, the generator cannot kick off. As soon
as the starter handle is pulled, the rope uncoils around the end of the crankshaft, spinning it to
crank the engine. This spinning action of the flywheel starts the engine. It is always important to
return the grip gently so as to avoid the rope being tangled in the mechanism thereby damaging
the starter. The rope is also liable to cut as time goes by but can be easily replaced.
In the case of large (and some medium) engine-generators, a key or on/off button could be used
as a means to start the generator in addition to the manual starter.
A Small Generator Starter
Battery: Batteries are only present in large and some medium generator. The key or on/off
button starter is operated by means of a battery and a battery charger is used to continuously
keep the battery charged by supplying it with a precise voltage. Battery chargers are usually
made of stainless steel to prevent corrosion. One problem with this method is the possibility of
the battery running down. When this happens, the recoil starter would have to be used to start the
Flywheel: This is a wheel or disc attached to the crank and which forms the inertial mass that
stores rotational energy. The flywheel is essential to carry energy over from the power stroke
into a subsequent compression stroke in single cylinder engines. In reciprocating engines, the
flywheel ensures smoothening out of the power delivery over each rotation of the crank while in
most automotive engines; the flywheel is used to mount a gear ring for a starter.
3.5 Cooling And Lubrication System
As the engine of a generator continues to work, the combustion in the internal combustion
engine generates a great deal of heat and some of this heat is transferred to the walls of the
engine. If the body of the engine is allowed to reach too high a temperature, failure will occur
either as a result of the engine physically failing or any lubricants used degrading to the point
that they no longer protect the engine. This brings about the need for cooling the generator
Cooling is a very important factor as it relates to the life and performance of the generator.
Under normal conditions, such cooling can be obtained through natural air circulation, but in
some cases it might be necessary to force fed air from atmosphere or another room to the
generator with the aid of the cooling fan of the alternator or the radiating fins of the cylinder
The moving parts in the of the internal combustion engine require lubrication so that they can
slide smoothly over each other. Insufficient lubrication subjects the moving parts of the engine to
metal-to-metal contact, friction, heat build-up, rapid wear which often culminates in parts being
friction welded together. Big end bearings seizing up will sometimes lead to a connecting rod
breaking and poking out through the crankcase. In a generator, engine oil is used
3.6 The Lighting System
The lighting system is the electrical system of the generator which ensures that the mechanical
energy is converted to electrical energy. It comprise of the following components discussed
Capacitor: This is a passive electrical component that is used to store energy in the electric field
between a pair of conductor (called plates). The process of storing charges is known as charging,
a process involves electric charges of equal magnitude, but opposite polarity building on each
plate. There are different types of capacitors which include paper capacitor, mica capacitor,
electrolytic capacitor and variable capacitor to mention a few. They supply the initial current to
excite the coils.
Commutator: It is a split metal ring mounted on the shaft of the armature which helps to
produce a steady flow of direct current. It is found in a DC generator to facilitate conversion of
alternating current induced in the armature to unidirectional current in the external load circuit
during each revolution. The two halves of the commutator rings are insulated from each other
and serve as the terminals of the armature coil.
Fixed brushes of carbon are held against the commutator as it revolves, connecting the coil
electrically to external wires. As the armature turns, each brush is in contact alternately with the
halves of the commutator, changing position at the moment when the current in the armature coil
reverses its direction. Thus there is a flow of direct current from the generator to the outside
circuit. DC generators are usually operated at fairly low voltages to avoid the sparking between
brushes and commutator that occurs at high voltage.
Rotor/Armature: It is the moving component and the current and voltage generated by the
generator depends on the spinning of this component. It produces a rotating magnetic field by
any of the following means:
– An exciter is a small source of direct current (DC) that energizes the
rotor through an assembly of conducting slip rings and brushes.
– These are known as brushless alternators and are usually used in large
– This is common in small alternator units
Stator/Field Coil: It is a stationary component which contains a set of electrical conductors
wound in coils over a laminated iron core. It is responsible for creating the magnetic field.
Top view of the field coil
The Alternator: The alternator is responsible for the energy conversion in a generator and
operates on the principle of Faraday‘s law of electromagnetic induction. The law states that
whenever a conductor cuts a magnetic flux, dynamically induce e.m.f is produced in it. This
e.m.f causes current to flow in the conductor circuit if it is closed.
Brush: This component is housed in a brush holder and mounted on a spindle. It is needed to
conduct current from the commutator. The amount of current to be conducted from the
commutator determines the number of brushes per spindle. It is usually made of carbon which is
why most people call it carbon brushes. It is mostly found in a brush-free alternator. It is
important to know that the coil of a rotor must be connected to complete the electrical circuit for
proper functioning of the generator. As a result of this, slip rings are affixed to the shaft, and
springs press brushes onto the rings which conduct the current. As the brushes are slowly
abraded, they have to be replaced. An alternator that does not use brushes requires less
maintenance and also produces cleaner power.
A typical carbon brush
Automatic Voltage Regulator (AVR): When a brush-free alternator is under load, an automatic
voltage regulator (AVR) is used for preventing the voltage from dropping and to keep it at a
stable level. Most generator uses capacitor while others uses the AVR but the 0.95KVA
generator only uses capacitor. The notable difference between capacitor and the AVR is that a
constant voltage is maintained (maximum voltage cannot be exceeded) for generator using AVR
while for those using capacitor, the voltage can be increased. A generator which uses diode and
resistor uses capacitor.
An Automatic Voltage Regulator
Diodes: A diode is a semiconductor device that allows current to flow in one direction only as a
result of which it is called a unidirectional device. The current from each of the three stator wires
is only allowed to pass in one direction with a special arrangement of the diodes. This
arrangement is manufactured as a single part and is referred to as the diode pack or diode trio.
Tools Used In Generators Workshops
There are so many tools used in the workshop for the assembling and disassembling, as well as
repair of generators. These workshop tools should always be handled with care to prevent
workshop hazards and damage to the tools and generator. The various tools used in the repair
and maintenance of a generator include;
Spanners: The standard name for spanner is wrench and it is a tool with which mechanical
advantage and grip is provided while applying torque to turn objects such as bolts and nuts. It is
also used at times to keep them from rotating. It is the most commonly used tool in a generator
repair and maintenance workshop. Most quality spanners are made from an alloy of chromium
and vanadium and are drop-forged. They could be chrome-plated to resist rusting and enhance
ease cleaning. They come in different forms and sizes and are as follows:
Socket spanner: This is a hollow cylinder which fits over one end of a nut or bolt head. It is
called so if it includes a handle otherwise; it is often just referred to as a socket. It can be used
with various drive tools to make it a spanner such as a ratchet a tee bar (sliding Tommy bar) bar
or a knuckle bar (single axis pivot). It normally has a six-point, eight-point or twelve-point recess
which may be shallow or deep, and may have a built-in universal joint.
Socket Spanner
Ring spanner: This is a one-piece spanner having an enclosed opening that grips the faces of
the bolt or nut. It is widely referred to as "the king of spanners”. The recess is generally a sixpoints or twelve-points opening for use with nuts or bolt heads which have hexagonal shape.
Usually, ring spanners are double-ended and usually with offset handles to improve access to the
nut or bolt.
Ring Spanner
Spark plug / tube spanner: This spanner is a six-sided socket on both ends which can be
turned with a short length of rod (Tommy bar or T-bar) inserted through two holes in the middle
of the tube. It is used for loosening and tightening of the spark plug on the cylinder cap.
Spark Plug Spanner
Combination spanner: A double-ended tool with one end being like an open-end wrench or
open-ended spanner, and the other end being like a box-end wrench or ring spanner. Usually,
both ends of the spanner generally fit the same size of bolt. I made use of spanners of sizes
ranging from 8mmto 32mm.
Flat/Open-ended spanner: It is a one-piece double ended spanner with each end having a Ushaped opening that grips two opposite faces of the bolt or nut. The ends are generally oriented
at an angle (about 150) to the longitudinal axis of the handle and this orientation allows a greater
range of movement in enclosed spaces by flipping the spanner over.
Fig. 5.4 Open-Ended Spanner
Allen key: This spanner is used to turn screw or bolt heads that are designed with hexagonal
sockets (recess) to receive the spanner. The spanner comes in two common forms-L-shaped and
T-handles. For the L-shaped spanners, they are formed from hexagonal wire stock while the T-
handles have in addition to the hexagonal wire stock, a metal or plastic handle attached to its
Allen Key
Pliers: This is called a two pin tool because of the teeth-end it has which is basically used to grip
and cut wires of different thickness. It can also be used in shaping or twisting wires and for
improvisation. For example, it is used to remove and fix the hose on the fuel tap and carburetor
and also to remove the key on the piston holding the rod in it firmly in place to the connecting
rod while servicing a 0.95KVA generator. A typical pliers have a pair of handles, the pivot (often
formed by a rivet), and the head section with the gripping jaws or cutting edges forming the three
File: This is mainly used to remove the carbon deposits from piston grooves and other suitable
generator parts. It is produced from hardened carbon steel with a soft tang to which the handle
can be fixed.
Rectangular File
When a file has a single series of teeth cut across its face, it is known as single-cut file and with
two sets of teeth cut across its face, and it is known as double-cut. The different kinds of files
used are half-rounded, file square file, round file, and triangle file which is based on nature of the
job at hand.
Screwdriver: This is a device that is specifically designed for inserting, tightening, loosening
and removing screws. The screw driver is at times used to remove carbon from a hole like the
grooves in the engine block. A typical hand screwdriver comprises an approximately cylindrical
handle of a size and shape held by a human hand and an axial shaft fixed to the handle. The tip is
shaped to fit a particular type of screw. The handle and shaft allow the screwdriver to be
positioned and supported and when rotated to apply torque or moment. It may be in form of
testers or just the ordinary.
Screw Driver (Flat and Star)
Hammer: This is the tool used when one intends to deliver an impact on an object. It is used for
fitting parts and breaking up objects and can also be used in straightening or beating metal sheets
into plain form. Its usual features are a handle and a head with most of the weight in the head.
There are different types of hammers used in the generator workshop but the common ones are
the ball-peen hammer and sledge hammer.
Multimeter: This tool is an electronic measuring instrument used to measure the output current
and voltage from the generator. It is also called Avometer and is of two forms – digial and
analog multimeter. A standard multimeter may include features such as the ability to measure
voltage, current and resistance. They are capable of measuring the capacitance, inductance and
temperature of an object.
A Digital Multimeter
Safety Rules Observed In Generators Workshops
One of the fundamental principles every engineer and technician should have at the back of their
mind when working is the fact that safety is first. This is very important in order to avoid
workshop hazards that could result in the loss of lives and property. As a result of this, I will be
listing some of the safety rules which must be adhered to while working in a generator
outbreak of fire since fuels like petrol are usually contained an used in the workshop.
Avoid touching the silencer when it is still hot especially while the engine is still running.
extremely flammable and may ignite after the engine has started.
Faults, their Causes and Remedies
Various faults occur in a generator which could be either minor or major. Minor faults include those
faults that occur outside the alternator or engine compartment and can be fixed easily while major
faults are those which occur inside the engine or alternator compartment and fixing such fault will
require dismantling the whole generator. Some of the common faults in gasoline generators, their
possible cause(s) and their remedies are discussed in the table below.
Possible Cause(s)
Generator Not Able a) Improper spark or
To Start
no ignition from the
spark plug
b) No lubricating oil
for generators with oil
c) Stiff crankshaft or
faulty armature
a) Spark plug washed
with fuel or replaced
b) Oil storage
compartment should
be gauged with oil
c) Crankshaft is fixed
but if the armature is
faulty, it is recoiled
Faulty Starter
a) In problems with
clearance, the
clearance is adjusted
to suit the ease of
pulling the starter
b) The component of
the starter is
reassembled for
detached rope.
a) Reduced clearance
between the valve
rocker and the valve
for loosed starter rope
b) For a stiff starter
rope, it occurs when
the clearance between
the valve rocker and
the valve could be too
c) When
is c) For faulty spring,
spring is
Unusual Engine Noise
a) Broken bearing key a) Bearing is replaced
b) Armature cover has b) Armature cover is
too much clearance
Unusual Smoking of Incomplete
combustion due to
a) Injected fuel not
well atomized
b) Engine overload
a) The injector is
checked with the
nozzle readjusted
b) Reduction in engine
a) The faulty AVR is
b) Readjust the
contacts of the circuit
breaker or replace it
c) Remove carbon
deposit blocking the
Oil Leakage
Voltage a) Faulty AVR
b) Faulty circuit
c) Bad spark plug
d) Blocked exhaust
cum silencer
a) Broken oil seal
b) Broken middle
parking / gasket
Excess Engine
In both cases, the
replaced with new
Oil a) Broken oil seal
a) The piston rings and
b) Clearance in the oil seal are replaced
cylinder caused by
piston movement with
poor ring functioning
When generators are brought for repair due to one fault or the other, it is necessary to determine
the fault in the generator so as such fault can be fixed. The process or series of steps taking to
ascertain the fault with a system is referred to as troubleshooting. In the case of generator
troubleshooting, it is the various steps taking to find the actual problem responsible for a
generator fault so as to fix and get the generator working properly again.
In order that troubleshooting is done smoothly without anything left aside, it is important to
develop a troubleshooting flowchart for each fault that could occur in a generator so that it will
serve as a guide. Fig 4.1 shows an example of a troubleshooting flow chart for a generator that
refuses to start.
According to the fig. 4.1, one of the steps in troubleshooting a generator which refuses to start is
to find out if the spark plug produces spark or not and the following steps below are followed:
nd the spark plug
While the following steps are used to determine if there is proper supply of fuel to the carburetor:
An Example of a Troubleshooting Flowchart
During the course of the SWEP program, I learnt a lot of practical skills which I will be sharing
in this chapter of my report. The most important practical skill learnt was the servicing of
gasoline generator of various sizes. The servicing of generators and many other skills learnt are
discussed as follows:
Servicing of Gasoline Generator
Servicing of a generator is deemed necessary when the generator’s efficiency reduces. Servicing
basically involves renewal and maintenance of a machine or its components. This becomes so
obvious when a generator fails to start, produces its low power output and so on. It requires
dismantling the components.
The following signs suggest that a generator needs servicing;
Majority of the jobs we handle daily in my place of placement are generator servicing. In every
10 jobs handled, servicing could be as much as 5. For medium and large gasoline generators,
servicing is deemed very easy and simple as it involves the changing of the lubricating oil,
checking of the spark plug and parts cleaning. But for the 0.95KVA generator, it involves a little
more work. The various steps taking during servicing is explained below:
Medium and Large Generators:
a) Open the oil storage compartment and empty the condemned oil in the compartment
b) Refill the compartment with a good product of fresh oil (e.g. Con-Oil) and gauge it before
closing the compartment.
c) Loosen the spark plug with the spark plug key and check if dirty or damaged.
d) Clean the spark plug if dirty or replace with new one if damaged. Make sure the spark plug is
tightened back using the spark plug key
e) Use fuel to clean the generator body parts.
Small (0.95KVA) Generator:
a) Loosen the bolt nuts to remove the fuel tank after detaching the fuel hose from the tap.
b) Loosen the exhaust silencer
c) Loosen the starter to have easy access to the cylinder block
d) The cylinder cap is removed as well as the cylinder block to get access to the piston
Loosening Bolts to Remove Cylinder Cap
e) The piston is then removed by removing the keys at both ends to allow the removal of the
f) The piston rings are removed and washed with fuel to remove carbon deposits. The piston is
also washed with fuel to remove the carbon content.
g) The cylinder cap is scrapped to remove carbon from it and the piston is fixed back and the key
replaced. The other parts are also reassembled.
h) The spark plug is removed and checked. It is replaced if bad beyond fixing otherwise; it is
washed with fuel and fixed back.
Various Activities During 0.95KVA Generator Servicing
Replacing Piston Rings
The worn piston ring will cause leakage in the cylinder, excessive consumption of lubricating oil
and fuel and reduction of the output of the engine. The steps we normally take to replace piston
rings are as follows;
rear cover of the crankcase is removed when dismantling with care taking not to damage
the rear cover gasket
nder bore from the cylinder head
-carbonized with a chip or brush
ng grooves are scraped off with a chip and
then piston is cleaned in fuel
-carbonized as well
liner about 20mm. If the gap is over 1mm, the ring is replaced.
installing into the cylinder. All the piston rings are then compressed in a guide tool and placed on
top of the liner before the assembling is tapped lightly into the cylinder liner with a wooden
Finally, the connecting rod cap is reinstalled, and the connecting rod bolts is tightened.
Adjustment of Valve Clearance
Without proper adjustment of valve clearance, the engine of a generator is likely not going to
start. So the intake and exhaust valve is normally adjusted to 0.1-0.2mm following the following
steps below;
air cowling
rench and the adjusting screw is turned on the rooker arm
with the screw driver
-0.2mm with the help of a feeler gauge
cylinder head cover is assembled.
Air Cleaner Service
This is another common generator problem that I learnt to fix during the SWEP program. When
the air cleaner of a generator is dirty, it will restrict air flow to the carburetor. In order to prevent
carburetor malfunction, the air cleaner should be serviced more frequently. If the engine is used
in extremely dusty areas, it is advised that the air cleaner should be serviced regularly. At the
company, petrol is usually used to clean the filter element which is risky as it can cause fire or
explosion. To prevent this, the element is thoroughly dried. Soapy water or a non-flammable
solvent is recommended.
Steps taking to service the air cleaner are as follows;
Thereafter, the element is removed.
the element, the engine will smoke during initial start-up.
e element is restored and the cover is reinstalled.
Fuel Sediment Cup Cleaning
For the carburetor to function properly, dirt and water which may be in the fuel tank needs to be
prevented from entering the carburetor. The fuel sediment cup performs this function and that is
why the sediment cup needs to be cleaned if the generator engine has not be run for a long time.
Steps taking to do this are as follows;
– ring and filter are
-ring, and filter are cleaned in petrol. Any non-flammable or high flash
point solvent will also do.
– ring, and sediment cup are reinstalled.
The Students’ Work Experience Program has helped me to apply my theoretical knowledge to
real practical situations. It opened my eyes to the various expectations from the engineer by the
society. I also learnt some of the challenges facing the profession and from experience, learnt
that safety is key in the profession.
The four weeks duration spent at Kunle Generator Repairs has provided me the opportunity to
master practical skills in servicing the petrol engine generator, especially the 0.95KVA
generator; as well as assembling and disassembling of internal combustion engine and alternator.
I also acquired practical skills in troubleshooting and fixing of faults in petrol engine generators.
I would rate my experience at Kunle Generator Repairs as worthwhile even though there seems
to be little relationship between my experience during the industrial training and class work.
Finally, I must congratulate my fellow colleagues and myself zealously participating in this
program. The skills and experience gathered during the course of this training cannot be
My recommendation is that renowned industries should be chosen for the industrial training as
this will enhance a better learning and ensure a secured environment for the students. Also, the
length of time of the training is rather short, if it can be elongated, the quantity and quality of
experience gained would be augmented.
Finally, SWEP should more flexible in the placement of students in industries so that students
will learn what truly interests them.