DIRE DAWA UNIVERSITY

INSTITUTE OF TECHNOLOGY
SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
ELECTRICAL POWER ENGINEERING STREAM
WEEKLY INTERNSHIP REPORT
HOSTING COMPANY NAME
THE MOTOR AND ENGINEERING COMPANY OF ETHIOPIA
S.C ( MOENCO)
ADVISOR: Mr. DAWIT A. (M.sc)

KALEAB BELETE E/613/10

 Table of contents
Content page no
Abstract ……………………..………………………
1. Chapter 1 the company
1.1 Introduction
1.2 Company history
1.3. Mission and vision statements……………….
1.4. Company service…………………………….
2. Chapter 2 internship description………………….
2.1. Introduction ………………………….
3. Chapter 3 Overview of the experience………………
Acknowledgment

First of all, I would like to thank almighty GOD for helps me in all aspects from
the start to the end. Secondly, I would like to express thankfulness to all those who
gave this opportunity to complete this internship specially , Dire Dawa
University School of Electrical and Computer Engineering to get some reference
and I would like to express deepest gratitude and profound thanks to Mr. Dawit A.
(Ms.c) for him tremendours effort to contribute for me by giving his positive
idea , constant encouragement and show direction how to follow my work in a
good way, and counseling up to the end of this internship.
Next, I want to express mine gratitude to my hosting company MOENCO ,
Management of moenco and HR(human resource) of company for allowing me
through this internship program. Also, special recognition to many staff
employees in the company for their hospitality and sharing knowledge.
 Declaration

I understand declare that this weekly internship is mine own work. I

confirm that: this work was done mainly for internship student at DIRE
DAWA UNIVERSITY institute of technology.

In this internship program I have seen /working in the main company

and branch, in main company in electric department work on electrical
system of vehicles repair and diagnose fault by using diagnostic trouble
code (DTC).And also repair alternator. The branch company work on
repair huge machinery for example construction machine, agricultural
machine, road making machine. So, in branch machinery working on
repair generator and repair all electrical machinery.
In this internship I am working/see -
- Working principle of generator & repair ,
- Repair & working principle of induction motor
& Alternator
- Working principle Electrical hoiest
Chapter 1 THE COMPANY

1.1. INRODUCTION
MOENCO is a subsidiary company of Inchcape PLC, a London based company
engaged in global distribution & retail leader in the premium and luxury
automotive sectors.

1.2. Company History

The motor and engineering company of Ethiopia (MOENCO) was established in
January, 1959. The founding members were: -Mr. Y.D Lappine, Imperial
Insurance Company, Ato Menassie Lemma (the Governor of the National Bank)
and other members.

Nine years later, MOENCO took over the TOYOTA franchise business for
Ethiopia when Inchcape, a London based international organization, became a
major shareholder and injected a considerable amount of capital. This was a
milestone moment in the firm’s journey to become the MOENCO of today

MOENCO Today
Today MOENCO is the largest automotive company in the country, with 12
sub-dealers in
,different locations of the country, almost in each region and eight branches in
Ethiopia representing over 20 brands. MOENCO has grown both in terms of size
and in terms of the modernization of its service shops and parts distribution
centers, which display a passion for creating the ultimate customer experience.
1.3. Mission and Vision Statements
Vision
To become the world most Trusted automotive distributor & retailer
Mission
Providing vehicle sales, parts and service in the world-class purpose-built center.
Providing Excelling service and many magic moments by customer friendly
service, Advisor, sales people, Toyota certified technician and support staff.
Minimizing time for the service of Toyota vehicle by using special service Shop,
genuine spare parts and sophisticated equipment.
1.4. SERIVIES PROVIDED BY THE COMPANY
MOENCO represents TOYOTA one of the great Automobile Company in the
world. Service that are given by MOENCO include PDI Service, Free Service
Check-up, Express Maintenance Service, General Repair, Body & Paint
Repair Service, Automotive and Machineries’ sales, Automotive and
Machineries’ part sales Annual Vehicle Inspection, Towing Service.

PDI Service (pre delivery Inspection)

Before delivering a new vehicle to the customers the pre delivery inspection is
done.
Periodic maintenance
MOENCO suggests Every vehicle to be periodically maintained in every 5,000km
or by the intervals of 3 months. Periodic maintenance will insure reliability,
high resale value, long life and maximum performance. To feel safe and to
have peace of mind bring your car to periodic maintenance and feel all the
peace you need.
Body and Paint Repair
MOENCO through a continued in-house and overseas training program and using
the state-of-the-art equipment manages to develop full-fledged Body and Paint
technicians who can correctly trouble shoot and carry out major and minor
Body & Paint repairs to mint condition.
General Repairs
General Repair Service comprises of units overhauling (like engines, automatic
and manual transmissions/transaxles, fuel injection pumps, differentials,
steering gearboxes, vane pumps, starters, alternators, etc.), and diagnosis &
repair of any malfunctions on the vehicle using the state-of-art equipment and
tools available in the Service Centers.
Other services

Annual vehicle inspection

MOENCO Provides annual inspection service to all Toyota, Daihatsu, Suzuki and
Lexus vehicles.
Automotive and machineries sales
MOENCO is the biggest automotive supplier for TOYOTA, DAIHATSU, LEXUS
& SUZUKI Vehicles. Furthermore, they supply different agriculture,
construction, industrial and other machineries to both private and public
sectors throughout the country.
Some of supplied vehicles
Machineries supplied
Parts Sales
 MOENCO also provides genuine parts for TOYOTA, SUZUKI, LEXUS
vehicles and other machineries
Towing Service
Free service Check up

MOENCO also provides free service checkup for vehicles that were
purchased from MOENCO for every 1,000 km & 5,000 km. Customers Only
need to pay for replacement of components like lubricant and filters
 Work Flow

Each part of the department works individually or they may work together when a
vehicle needs several works to be done. So, there is a work flow starting from
reception to delivery. The entire work flow can be shown on the following diagram

,Maintenance and repair services work flow

Express Station

The express station mainly gives services to new and relatively new vehicles.
Meaning only vehicles under 150,000 mileages get service at the express station.
Since most of the work at this station involved new vehicles, the only tasks were
Services Type A-to-D.
Most of the work I participated in was type A&B services. Which involved oil
change, oil filter change brake pad and shoe cleaning (with water and sandpaper)
and handbrake adjusting. During type a service we did a visual inspection on the
brake pads before removing the tires.
Service types
Each service type is given at this specific kilometer
Service type A @= 5/15/25 /35/45/ 55/65/75,000 km
Service type B @= 10,000/30,000/ 50,000 and 70,000km
Service type C @= 20,000 and 60,000 km
Service type @ D= 40,000 and 80,000 km
Maintenance Station

At the maintenance station most of the services tasks are similar to the express
station but with the difference in the milage of the vehicles. As all machines, when
a vehicle is used for a longer time the parts that need service also increase due to
aging. At the maintenance station vehicles that have a milage between 150,000 and
300,000 are given both repair work and basic service.

Fig Maintenance station, tools used

Repair AB

The repair station is a place where vehicles with milage greater than 300,000 kms
get repaired and also given maintenance work.
since most of the vehicles in this section have been in used for substantial amount
of time, they require several types of services and repairs for every vehicle. At
repair station a Type C&D Services are most common

Body repair department

Under the body department there two stations

 chassis alignment, wheel alignment station and

 The chassis alignment station uses a machine called car-o-liner

used to repair damage to the inner frame of vehicle from
collisions, to restore it to its original shape. It enables vehicles
bodies to be repaired to their original shape with a very small
tolerance (+_ 3mms)
the Body workshops
Electric

This is where the electrical part of the car is checked and repaired. Some of the
activities are:

 Check and maintenance of all the lighting

system
 Check and replacement of car battery
 Check and repair of alternator and starter
 Check and repair of Air conditioning
system
 Check and maintenance of all the
electrical system inside the car.

1. Some of the work I have participated include:

 Refilling AC refrigerant.
 Fixing starter motor of a car.
 Install alarm system of a car.
 Replace head and tail light bulbs.
 Fix ABS, window motor, central door lock, horn assembly.
 Fix the dash board (gauge, entertainment system).

Chapter 3 Experience gained

Summary of the experiences gained throughout our internship program

Hard Skills
* Understanding of different electrical components (stator , rotor, relay …
and power flow elements).
* Understanding basic electrical installation
* Hybrid vehicles
* Electrical machine
* Automotive Repair Electric
* Electrical hoist

Soft skills
* Teamwork
* Problem-solving
* Decision-making
* Critical thinking
* Time management
* Communication
* Networking
* Leadership
* Decision-making
An Executive Summary of the Internship Report

The industrial internship report written by us in detail contains the fundamental

job and activities that had been able to model it as tangible activities and
performance. Also various activities were recorded that we were able to perform
them by ourselves at the end of internship duration (period). In addition to these,
different activities that are thought in the company by our supervisor and mentor
were included. Although all details information (data) those have been observed
and understood had not been mentioned, major points were tried to be written.
Some information’s were not explained in this report, because of their complexity
and interconnection with other fields of study. Generally, this report focused on
what the company looks like and the activities during internship including overall
organization of the MOENCO, work flow of the MOENCO, and overall benefit of
internship.
 How Does a Generator Create Electricity? How Generators Work

Generators are useful appliances that supply electrical power during a power
outage and prevent discontinuity of daily activities or disruption of business
operations. Generators are available in different electrical and physical
configurations for use in different applications. In the following sections, we will
look at how a generator functions, the main components of a generator, and how a
generator operates as a secondary source of electrical power in residential and
industrial applications.

How does a generator work?

An electric generator is a device that converts mechanical energy obtained from an
external source into electrical energy as the output.

It is important to understand that a generator does not actually ‘create’ electrical

energy. Instead, it uses the mechanical energy supplied to it to force the movement
of electric charges present in the wire of its windings through an external electric
circuit. This flow of electric charges constitutes the output electric current supplied
by the generator. This mechanism can be understood by considering the generator
to be analogous to a water pump, which causes the flow of water but does not
actually ‘create’ the water flowing through it.

The modern-day generator works on the principle of electromagnetic induction

discovered by Michael Faraday in 1831-32. Faraday discovered that the above
flow of electric charges could be induced by moving an electrical conductor, such
as a wire that contains electric charges, in a magnetic field. This movement creates
a voltage difference between the two ends of the wire or electrical conductor,
which in turn causes the electric charges to flow, thus generator electric current.

Main components of a generator

The main components of an electric generator can be broadly classified as follows:

 Engine
 Alternator
 Fuel System
 Voltage Regulator
 Cooling and Exhaust Systems
 Lubrication System
 Battery Charger
 Control Panel
 Main Assembly / Frame

A description of the main components of a generator is given below.

Engine
The engine is the source of the input mechanical energy to the generator. The size
of the engine is directly proportional to the maximum power output the generator
can supply. There are several factors that you need to keep in mind while assessing
the engine of your generator. The manufacturer of the engine should be consulted
to obtain full engine operation specifications and maintenance schedules.

(A) Type of Fuel Used – Generator engines operate on a 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. Certain engines can also operate on a dual
feed of both diesel and gas in a bi-fuel operation mode.
(B) Overhead Valve (OHV) Engines versus non-OHV Engines – OHV engines
differ from other engines in that the intake and exhaust valves of the engine are
located in the head of the engine’s cylinder as opposed to being mounted on the
engine block. OHV engines have several advantages over other engines such as:

• Compact design
• Simpler operation mechanism
• Durability
• User-friendly in operations
• Low noise during operations
• Low emission levels

However, OHV-engines are also more expensive than other engines.

(C) Cast Iron Sleeve (CIS) in Engine Cylinder – The CIS is a lining in the
cylinder of the engine. It reduces wear and tear, and ensures durability of the
engine. Most OHV-engines are equipped with CIS but it is essential to check for
this feature in the engine of a generator. The CIS is not an expensive feature but it
plays an important role in engine durability especially if you need to use your
generator often or for long durations.

Alternator

The alternator, also known as the ‘genhead’, is the part of the generator that
produces the electrical output from the mechanical input supplied by the engine. It
contains an assembly of stationary and moving parts encased in a housing. The
components work together to cause relative movement between the magnetic and
electric fields, which in turn generates electricity.
 
(A) Stator – This is the stationary component. It contains a set of electrical
conductors wound in coils over an iron core.
(B) Rotor / Armature – This is the moving component that produces a rotating
magnetic field in any one of the following three ways:

(i) By induction – These are known as brushless alternators and are usually used in
large   generators.
(ii) By permanent magnets – This is common in small alternator units.
(iii) By using an exciter – An exciter is a small source of direct current (DC) that
energizes the rotor through an assembly of conducting slip rings and brushes.

The rotor generates a moving magnetic field around the stator, which induces a
voltage difference between the windings of the stator. This produces the alternating
current (AC) output of the generator.

The following are the factors that you need to keep in mind while assessing the
alternator of a generator:

(A) Metal versus Plastic Housing – An all-metal design ensures durability of the
alternator. Plastic housings get deformed with time and cause the moving parts of
the alternator to be exposed. This increases wear and tear and more importantly, is
hazardous to the user.
(B) Ball Bearings versus Needle Bearings – Ball bearings are preferred and last
longer.
(C) Brushless Design – An alternator that does not use brushes requires less
maintenance and also produces cleaner power.

Fuel System
The fuel tank usually has sufficient capacity to keep the generator operational for 6
to 8 hours on an average. In the case of small generator units, the fuel tank is a part
of the generator’s skid base or is mounted on top of the generator frame. For
commercial applications, it may be necessary to erect and install an external fuel
tank. All such installations are subject to the approval of the City Planning
Division.  Click the following link for further details regarding fuel tanks for
generator.

Common features of the fuel system include the following:

(A) Pipe connection from fuel tank to engine – The supply line directs fuel from
the tank to the engine and the return line directs fuel from the engine to the tank.
(B) Ventilation pipe for fuel tank – The fuel tank has a ventilation pipe to prevent
the build-up of pressure or vacuum during refilling and drainage of the tank. When
you refill the fuel tank, ensure metal-to-metal contact between the filler nozzle and
the fuel tank to avoid sparks.
(C) Overflow connection from fuel tank to the drain pipe – This is required so that
any overflow during refilling of the tank does not cause spillage of the liquid on
the generator set.
(D) Fuel pump – This transfers fuel from the main storage tank to the day tank.
The fuel pump is typically electrically operated.
(E) Fuel Water Separator / Fuel Filter – This separates water and foreign matter
from the liquid fuel to protect other components of the generator from corrosion
and contamination.

(F) Fuel Injector – This atomizes the liquid fuel and sprays the required amount of
fuel into the combustion chamber of the engine.

Voltage Regulator
As the name implies, this component regulates the output voltage of the generator.
The mechanism is described below against each component that plays a part in the
cyclical process of voltage regulation.

(1) Voltage Regulator: Conversion of AC Voltage to DC Current – The voltage

regulator takes up a small portion of the generator’s output of AC voltage and
converts it into DC current. The voltage regulator then feeds this DC current to a
set of secondary windings in the stator, known as exciter windings.
(2) Exciter Windings: Conversion of DC Current to AC Current – The exciter
windings now function similar to the primary stator windings and generate a small
AC current. The exciter windings are connected to units known as rotating
rectifiers.
(3) Rotating Rectifiers: Conversion of AC Current to DC Current – These rectify
the AC current generated by the exciter windings and convert it to DC current.
This DC current is fed to the rotor / armature to create an electromagnetic field in
addition to the rotating magnetic field of the rotor / armature.
(4) Rotor / Armature: Conversion of DC Current to AC Voltage – The rotor /
armature now induces a larger AC voltage across the windings of the stator, which
the generator now produces as a larger output AC voltage.
This cycle continues till the generator begins to produce output voltage equivalent
to its full operating capacity. As the output of the generator increases, the voltage
regulator produces less DC current. Once the generator reaches full operating
capacity, the voltage regulator attains a state of equilibrium and produces just
enough DC current to maintain the generator’s output at full operating level.

When you add a load to a generator, its output voltage dips a little. This prompts
the voltage regulator into action and the above cycle begins. The cycle continues
till the generator output ramps up to its original full operating capacity.

Cooling & Exhaust System

(A) Cooling System
Continuous usage of the generator causes its various components to get heated up.
It is essential to have a cooling and ventilation system to withdraw heat produced
in the process.

Raw/fresh water is sometimes  used as a coolant for generators, but these are
mostly limited to specific situations like small generators in city applications or
very large units over 2250 kW and above. Hydrogen is sometimes used as a
coolant for the stator windings of large generator units since it is more efficient at
absorbing heat than other coolants. Hydrogen removes heat from the generator and
transfers it through a heat exchanger into a secondary cooling circuit that contains
de-mineralized water as a coolant. This is why very large generators and small
power plants often have large cooling towers next to them.  For all other common
applications, both residential and industrial, a standard radiator and fan is mounted
on the generator and works as the primary cooling system.

It is essential to check the coolant levels of the generator on a daily basis. The
cooling system and raw water pump should be flushed after every 600 hours and
the heat exchanger should be cleaned after every 2,400 hours of generator
operation. The generator should be placed in an open and ventilated area that has
adequate supply of fresh air. The National Electric Code (NEC) mandates that a
minimum space of 3 feet should be allowed on all sides of the generator to ensure
free flow of cooling air.

(B) Exhaust System

Exhaust fumes emitted by a generator are just like exhaust from any other diesel or
gasoline engine and contain highly toxic chemicals that need to be properly
managed. Hence, it is essential to install an adequate exhaust system to dispose of
the exhaust gases.  This point cannot be emphasized enough as carbon monoxide
poisoning remains one of the most common causes for death in post hurricane
affected areas because people tend to not even think about it until it’s too late. 

Exhaust pipes are usually made of cast iron, wrought iron, or steel. These need to
be freestanding and should not be supported by the engine of the generator.
Exhaust pipes are usually attached to the engine using flexible connectors to
minimize vibrations and prevent damage to the generator’s exhaust system. The
exhaust pipe terminates outdoors and leads away from doors, windows and other
openings to the house or building. You must ensure that the exhaust system of your
generator is not connected to that of any other equipment. You should also consult
the local city ordinances to determine whether your generator operation will need
to obtain an approval from the local authorities to ensure you are conforming to
local laws a protect against fines and other penalties.

Lubricating System
Since the generator comprises moving parts in its engine, it requires lubrication to
ensure durability and smooth operations for a long period of time. The generator’s
engine is lubricated by oil stored in a pump. You should check the level of
lubricating oil every 8 hours of generator operation. You should also check for any
leakages of lubricant and change the lubricating oil every 500 hours of generator
operation.

Battery Charger
The start function of a generator is battery-operated. The battery charger keeps the
generator battery charged by supplying it with a precise ‘float’ voltage. If the float
voltage is very low, the battery will remain undercharged. If the float voltage is
very high, it will shorten the life of the battery. Battery chargers are usually made
of stainless steel to prevent corrosion. They are also fully automatic and do not
require any adjustments to be made or any settings to be changed. The DC output
voltage of the battery charger is set at 2.33 Volts per cell, which is the precise float
voltage for lead acid batteries. The battery charger has an isolated DC voltage
output that does interfere with the normal functioning of the generator.
Control Panel
This is the user interface of the generator and contains provisions for electrical
outlets and controls. The following article provides further details regarding the
generator control panel. Different manufacturers have varied features to offer in
the control panels of their units. Some of these are mentioned below.
(A) Electric start and shut-down – Auto start control panels automatically start
your generator during a power outage, monitor the generator while in operation,
and automatically shut down the unit when no longer required.
(b) Engine gauges – Different gauges indicate important parameters such as oil
pressure, temperature of coolant, battery voltage, engine rotation speed, and
duration of operation. Constant measurement and monitoring of these parameters
enables built-in shut down of the generator when any of these cross their respective
threshold levels.
(c) Generator gauges – The control panel also has meters for the measurement of
output current and voltage, and operating frequency.
(d) Other controls – Phase selector switch, frequency switch, and engine control
switch (manual mode, auto mode) among others.

Main Assembly/Frame
All generators, portable or stationary, have customized housings that provide a
structural base support. The frame also allows for the generated to be earthed for
safety.

Induction motor

An induction motor (also known as an asynchronous motor) is a commonly used

AC electric motor. In an induction motor, the electric current in the rotor needed
to produce torque is obtained via electromagnetic induction from the rotating
magnetic field of the stator winding. The rotor of an induction motor can be a
squirrel cage rotor or wound type rotor. Induction motors are referred to as
‘asynchronous motors’ because they operate at a speed less than their
synchronous speed
Synchronous Speed
Synchronous speed is the speed of rotation of the magnetic field in a rotary
machine and it depends upon the frequency and number poles of the machine.
An induction motor always runs at a speed less than synchronous speed because
the rotating magnetic field which is produced in the stator will generate flux in
the rotor which will make the rotor to rotate, but due to the lagging of flux
current in the rotor with flux current in the stator, the rotor will never reach to its
rotating magnetic field speed.
Rotating Magnetic Field
When a 3-phase winding is energized from a 3-phase supply, a rotating magnetic
field is produced. This field is such that its poles do not remain in a fixed position
on the stator but go on shifting their positions around the stator. For this reason,
it is called a rotating field. The magnitude of this rotating field is constant and is
equal to 1.5 Φ m. where Φ m is the maximum flux due to any phase.
Working Principle of Induction Motor
The motor which works on the principle of electromagnetic induction is known as
the induction motor. The electromagnetic induction is the phenomenon in which
the electromotive force induces across the electrical conductor when it is placed
in a rotating magnetic field. When the three phase supply is given to the stator,
the rotating magnetic field produced on it. The figure below shows the rotating
magnetic field set up in the stator. The polarities of the magnetic field vary by
concerning the positive and negative half cycle of the supply. The change in
polarities makes the magnetic field rotates. The conductors of the rotor are
stationary. This stationary conductor cut the rotating magnetic field of the stator,
and because of the electromagnetic induction, the EMF induces in the rotor. This
EMF is known as the rotor induced EMF, and it is because of the electromagnetic
induction phenomenon
Construction of Induction Motor
A three phase Induction motor mainly consists of two parts called as the Stator
and the Rotor. The stator is the stationary part of the induction motor, and the
rotor is the rotating part. The construction of the stator is similar to the three-
phase synchronous motor, and the construction of rotor is different for the
different machine. Construction of Stator The stator is built up of high-grade alloy
steel laminations to reduce eddy current losses. It has three main parts, namely
outer frame, the stator core and a stator winding. Outer frame It is the outer body
of the motor. Its main function is to support the stator core and to protect the
inner parts of the machine. For small machines, the outer frame is casted, but for
the large machine, it is fabricated.
Stator Core
The stator core is built of high-grade silicon steel stampings. Its main function is
to carry the alternating magnetic field which produces hysteresis and eddy
current losses. The stampings are fixed to the stator frame. Each stamping are
insulated from the other with a thin varnish layer. The thickness of the stamping
usually varies from 0.3 to 0.5 mm. Slots are punched on the inner side of the
stampings to accommodate stator winding.
Stator windings

The core of the stator carries three phase windings which are usually supplied
from a three-phase supply system. The six terminals of the windings (two of each
phase) are connected in the terminal box of the machine. The stator of the motor
is wound for a definite number of poles, depending on the speed of the motor. If
the number of poles is greater, the speed of the motor will be less and if the
number of poles is less than the speed will be high. As the relationship between
the speed and the pole of the motor is given