How to judge skills and knowledge ?
Perspective theoretical knowledge of project-report exam no. 1 chapter 2
Electricity Sources.
What is Electricity Sources?
Electricity sources are areas of high electrical potential. This means that the region/area has a net negative charge, that is to say high number of free electrons. Electricity is created when these areas of potential discharge their electrons into neighbouring areas of lower potential because it is by definition the flow of electrons from high to low potential. Most man-made electricity is created using some form of generator.
Generators are devices that convert mechanical energy into Electrical energy. Typically, this is done by rotating high powered magnets inside tightly coiled copper wiring. The magnet essentially tears electrons off the copper atoms creating high negative potential within the wire. The resulting flow of electrons out of the generator through wiring to areas of less potential is electricity.
In nature we see electricity when high negative potential builds within storm clouds because friction between water droplets tears electrons free. The negatively charged clouds discharge into the ground below in the form of lightening which is dangerous to the flats and storage buildings. Solution for this lightening is solved by installing lighten protection unity.(most of the information is got from http;//en.wikipedia.org/wiki/Electrical generator, power generator)
Basic Electricity Energy concepts.
What are the basic Electricity Energy concepts?
A basic understanding of Electricity Energy concepts is necessary before undertaking any Electricity Energy source system installation and design.
Energy is referred to as the ability to work. It is measured in units called joules (j), in watt hours (wh).Ampere hours (Ah).
Power is the rate at which energy is supplied ( or energy per unit time), and is measured in watts (w).
Efficiency is the ratio of output energy to input energy. In case of solar electric systems,the input energy is the energy received from the modules and the sun by the modules and the output energy is the electricity available for lights and appliances. An energy- efficient device uses less energy to perform a given task. Efficiency is measured as a percentage; the higher the percentage, the more efficient the transfer is.
The types, function and construction of Electricity source?
What are the types, functions and construction of Electricity sources?
The types, functions and construction of each Electricity sources are as follows;-
Water- Hydroelectric power energy;-
is produced when water falls from a high place to a low place. Hydroelectric power energy contains a turbine driven by falling water from a dam.
''DAM'';- is a barrier that is built or constructed across a river in order to stop the water from flowing, used especially to make a reservoir to produce electricity. The turbine drives the generator. This form of energy produces little pollution; it does not ruin the water. The water still can be used for other purposes.
What are the advantages of hydroelectric power energy?
The advantages of hydroelectric power energy are;
Hydroelectric power energy does not cost any more than fossils fuels.
It provides rapid growth of economy and development in the country.
It creates high employment opportunity in the country.
It promotes information and communication technology system of the country easily.
It promotes fishing activities in the lake it creates.
Another, advantage is that, there are rivers where a dam can be built or constructed in the countries and the world at large to produce hydroelectric power energy.
What are the disadvantages of hydroelectric power energy?
The disadvantages of Hydroelectric power energy are;-
It needs high senior technical know how’s to the construction of Hydroelectric power dam.
It is very expensive in constructing dam.
When a dam is built or constructed, a huge area is flooded and create a lake, which in turn displaces the people and animals living within the area.
Fish such as salmon, can not climb over the dam, so the dam changes the environment.
In Southern Sudan, such sites were observed and spotted in river Nile are two, one is Fulla falls at Nimule, magwe county eastern equatorial state, another is at lologo, juba county, central equatorial state and last which needs renovation at maridi western equatorial state. These dams were plan and fund for construction was also been proved by Government of national unity under national project development.
Chemical reaction-Nuclear power energy or uranium-nuclear coal.
Is made by fusion and fission. It is produced in the reactor of a nuclear power station. The energy turns water into steam, which drives a turbine that powers a generator. Nuclear power produces lots of energy and can be made to power major cities to avoid load shading, (load shading means that, removing of fuse from transformer in order not to supply an area). This energy, unlike other sources, produces lots of radio active waste.
If that waste gets released, it could devastation to a large area. It warms its waste water, so fish in the nearby lake might lay their eggs at any time of years in the warmed spot. Some fish such as trout can not live in warm water.
This type of Electricity source is not there in south Sudan and probably in the Africa continent at large. Except in the develop countries such as USA, Japan and so many others.
Wind power energy.
Is produced by the wind turning a turbine, wind power, through using windmill, has been know for many centuries. This source of energy produces almost no pollution. Some people think that the fields of some other people are bothered by the noise generated by windmill. Also in order to be effective, the wind speed at a power site has to be over 12km/hr.
Finally, this source of power is costly and requires special equipment. Also, probably it is not there in South Sudan.
Fossil fuels.
Is a material that can be burned and that comes from the fossils remains of animals and plants, such as long-dead dinosaurs. Some examples of fossil fuels are coal, nature gas and petroleum. It is not dependent upon the weather. This source is currently available in the developt countries and is not there in Southern Sudan.
What are the disadvantages of fossil fuel?
- Fossil fuel causes pollution.
- It is not renewable resource.
- It needs to be mined from the earth.
- It causes acid precipitation which destroys life in lakes.
Sun light-solar energy.
What is a solar Electricity?
A solar electricity is electric power generated from sun light by using devices called solar cell modules.
Or it is the electricity source of energy that comes from the sun captured by solar panels.
How is solar cell modules generate solar electricity from sun lights?
Solar cell modules generates solar electricity from sun light by using solar radiation.
This solar radiation is composed of millions of tiny high energy particles called photons.
Each photon carries a quantity of energy, some have more than others.
When a photon of sufficient energy strikes a silicon atom in a solar cell, it pushes the outermost silicon electron out of its orbit around the nucleus, freeing it to move across the cell's electric field.
Solar cells rely on the special electric property of the element silicon (or other semiconductor materials) which enables it to act as both an insulator and a conductor. Specially-treated pieces of silicons ''sort'' electrons dislodge by solar energy in one direction to produce an electric current.
If a load is connected between the negative and positive side of the cell, the electrons flow as a current. Thus, solar energy ( in the form of photons) continuously dislodge silicon electrons from their orbital and '' pushes'' the electrons through the wires. More intense sun light gives a stronger current. If the lights stops striking the cell, the current stops flowing immediately.
How much Energy does a solar module produce?
The maximum amount of energy that a solar module produces per day varies from locations or sites where they needed to be installed, especially in Southern Sudan states. This can be estimated roughly, multiplying the peak power rating of the module by the number of peak sun hours received by module over the course of the day. The actual energy output will be less, depending on how near to the peak power point the module is operated.
Note the following.
Peak power rating;- of the module is the amount of power a solar cell module can be expected to deliver at noon on a sunny day when it is facing directly towards the sun at STC, that is to say Standard Test Conditions which are 1000w/metre square of solar irradiance, a temperature of 25 degree Celsius, and an air mass of 1.5.
while peak sun hours;- is the number of hours per day during which solar irradiance average 1000w/metre squared at the site.
Maximum energy produce by a module = peak power rating x peak sun hours at site
(in watt hours per day) (in WP)
but in the field work, we take inquire on appliances needed and location of the site, which will show you clear decision of adding the number of batteries and solar panel and the types which will fit for the particular location.
What are the advantages of solar Electricity?
The advantages of solar electricity are as follows.
- Solar electricity system consumes no fuel. Solar cell modules convert freely available sunlight directly into electricity without being used up.
- They produce electricity quietly, without giving off exhaust gases or other pollutants.
- Compared to conventional generators, solar electric systems require very little maintenance. Solar modules have no moving parts and last for over 20 years.
- Solar electric systems are economical for many small applications. While the price of oil has steadily risen over the past few years, the price of solar cells has been falling. In the long term, it is often cheaper to power lights, small tools, stereo systems and televisions with solar energy than it is to power them with dry cells, lead-acid batteries or generators.
- Solar electric systems can be tailored to the power needs of individual applications from tiny electric calculators, to small radios televisions and lights, to electric boreholes pumps.
- Solar electric systems can be expanded easily by adding more modules and batteries.
- Properly installed solar electric systems are safe.
- A risk of electric shock is small because of the low system voltage.
- Fire risks are lower in homes and schools lit by solar electricity than those lit with kerosene lanterns.
What are the disadvantages of solar Electricity?
The disadvantages of solar Electricity are;-
- The initial cost of solar electric system is relatively high by rural standards. Even if a solar lighting system is more economical over its life time than kerosene or generators, it is still very difficult for many people to raise the cash to buy systems all at once.
- Solar electric systems require batteries for energy storage. Batteries must be carefully maintained. The performance of system is dependent on the quantity of batteries available on the local market or the availability of imported batteries.
- Appliances and lamps which run on low voltage are not as readily available as those that run on mains power. However, as more and more people install solar electric systems, the supply of 12 volt DC appliances is increasing.
- There is a lack of trained technicians to design and install solar electric systems. Because of this, poorly designed systems are sometimes installed by untrained individuals, reflecting badly on the solar electric technology. (most of the information is got from small solar Electric system for Africa)
Magnetism-Generators.
What is magnetism?
Magnetism is a force of attraction or repulsion that acts at a distance due to a magnetic field, which is caused by moving electrically charged particles or is inherent in magnetic objects such as a magnet. (www.school-for-champions.com/science/magnetism.htm)
What are generators?
In Electricity generation, an electric generators are devices that converts mechanical energy into electrical energy. (http;/en.wikipedia.org/wiki/Electrical generator)
How do Generators work?
Generators work by spinning a copper coil between two magnets, to create a steady flow of electrons. Generators are fueled by burning a variety of fuels, primarily natural gas.
What types of fuels do generators use?
Generators can be powered by natural gas, propane, gasoline(petrol), LP(fuel. liquefied petroleum gas) gas, diesel and bio diesel. But in Southern Sudan mostly, people are using diesel generators very few are using gasoline(petrol)
What types of Generators are there?
Generators rang from portable to industrial size, ranging in wattage from a few hundred watts to 30kw. Generators differ in physical size and amount of noise it makes. Some generators can sense power outages and will restore power.
Note. A power outage ( also blackout or power failure) is a short- or long term loss of the electric power to an area.(en.wikipedia.org/ wiki/ Power-outage)
This type of generator is there in Southern Sudan but mostly been used by Telecommunication companies at their anternar receive stations.
There are two types which commonly being used in South Sudan;-
Gasoline-power Generator and Natural gas Generator.
Gasoline- power Generator;- is a simple, fairly cheap solution. It rang from 250 watt ( 2.5kw)- 3500watt( 3.5kw) generators that could run lights and appliances in many homes, office to mention but few.
What are the advantages and disadvantages of gasoline-power generators?
The advantages of gasoline-power generator are;-
it is very cheap to afford.
It is portable.
It is easy to operate.
It does not need bleeding when fuel run out of it.
The disadvantages of gasoline-power generator are;-
Gasoline Generators are noisy.
They pollute environment.
They are increasingly expensive in maintenance.
It needs to be turn on, if the main power goes off.
It needs to be switch off, if once needed to sleep.
They only use petrol.
It limits in using electrical appliances.
It doe not fit in factories and small industries.
Gasoline generators run more than six hours above.
Natural gas generator.
Are cleaner and quiter than gasoline engines. Some will even sense a power outage, safely restoring power in less than a minute. Many natural gas generators will also run on liquefied petroleum gas(LP).
In South Sudan, the only type of generator is nonsense power outage restoring power generator.
What are the advantages and disadvantages of Natural gas generator?
The advantages of Natural gas generators are;-
Natural gas generators supplies electrical energy in large areas if transformer is used.
It can be operated when the operator is well instructed.
If it is well serviced can run for 24 hours.
If it is well installed, it will generate good electrical energy.
Some can run under rain without causing electrical short circuit.
The disadvantages of Natural gas are;-
Natural gas generators need a trained personal to install and operate it.
It is very cost when buying and maintaining it.
It needs daily checking before starting any fuel generator.
Mechanical and electrical faults occur at any time when the generator is running or after running.
How to generate electricity?
Electrons are part of every atom, electricity is what results when electrons are flowing through a conductor. Ultimately, all that is needed to generate electricity is a metal wire for a conductor and a catalyst to start the electrons flowing.
How does a conductor produce electricity?
The most common method for generating electricity is moving a magnet around a conductor.
When talking about different sources of electricity , it refers to the different types of fuel or power used to generate electricity, but except for solar power, they all involve spinning a copper wire between magnets.
When a magnetic field is in motion relative to a copper wire it triggers the flow of electrons in the wire, creating electricity.
Electrical generators use large magnets posited on a shaft called an armature-spinning inside large quantities of copper wiring at very high speeds. This process gets electricity moving through the copper wires. Electricity can also be generated by spinning lots of wire inside of big magnets. The more coils they are and the faster they spin, the more current is produced by the generator.
In power plants, most often the armature is turned by the force of water or steam. Electrical generators are most often powered by natural gas.
Steam turbine generators, gas turbine generators, diesel engine generators, nuclear power and alternate energy systems, all follow this principle, each providing a unique way to spin the armature.
Still improvement is needed for this process in search of energy solutions that carry the least cost when both the expense of generating it and the cost of damage to the health of people and the environment.
An Electrical generator is identical to a motor, when electricity is created by spinning the shaft is called a generator, when an electric current is hooked to it the electricity forces the wires to spin the shaft it will be called motor.
This is my major interest of learning in Bachelor's Degree programme in Technical Vocation Education for Teacher upper Nile university- Malakal.
Perspective Documentation of skills Performance in the
Electrical installation work.
What is Electrical installation work am I able to do in the Electrical installation work?
Electrical installation work which I can able do are;-
Generating Electrical energy from mechanical energy in generators, then transmitting this Electrical Energy into step up transformer and again into step down transformer and distributing this Electrical Energy to the consumers premises. Not only these, I can also be able to do Electrical installation wiring of conference halls, offices, Guest houses and commercial buildings or shops.
In construction of Roads and bridges camp sites, I can also be able to do Electrical installation wiring in caravans, mechanical workshop and temporary houses within the camp site where Electrical power is needed.
I am here going to take Electrical installation wiring in Guest house, caravans and office for next subheading.
Skill by skill in electrical installation wiring in brick wall.
Electrical installations wiring in the guest houses, offices and caravans have difference and similarities.
What are the differences and similarities of Electrical installation wiring in guest houses, offices and caravans?
The differences and similarities of Electrical installation of following;-
Guest house;- is a residential types of building which contains different electrical installation wiring from its working drawings which includes room sizes such as master's bedroom self contain, family room, visitors room, boy's room, sitting room, dinning room, garage, kitchen, toilet and bath room.
Positioning of electrical accessories such as single pole switches, two way switches, switched socket outlets, unswitched socket outlet, wall lighting points, water heater, water heater switch, cooker control unit, wall fans, decorated lighting points for sitting room and dinning room, ceiling fixed stand fan or ceiling fan rod type, compound decorated security lamps to mention but few.
PVC Plastic conduits in different sizes in millimeter diameter, metallic mk boxes, grooving or chasing wall, PVC flat gray twin with or without earth cable in different across sectional diameter, security lamps, main switch.
Installation of Air conditions varies on the sizes to be installed in the rooms also depend on sizes of room. For example, Guest houses mostly has 3m-3.5m which needs 2.5ft Air condition, split type or window type. In guest house 2.5ft air conditions are been used because area of room very small and it is cooling the room very fast. Second reason is that, only a person or two leaves in the room not like in the offices.
Earthling of the electrical installation wiring of the Guest house.
Installation of lightening protection unit on the guest house.
The difference of electrical installation wiring in office.
Is in electrical accessories such as wall bracket lighting points, decorated ceiling lighting points and cooker control unit which are not necessarily to install in the office unless it is a request to be install. But in electrical regulation is not indicated.
The size of the electrical accessories varies. For example, Air conditions to be install in the office is 4ft big size to that of guest house in a reason that, it is to cool and met the cooling load sources of particular rooms where air condition is installed.
Cooling load source; - means that, heat, warm air which are entering into cool room.
The cooling load source is made up of from the following sources;
Heat conducted through the walls.
Heat radiated in through windows.
Warm air coming in through gas under door.
Heat emitted from the electrical equipments in the room.
Heat given out by people.
What are the similarities of Guest house and office electrical installation wiring?
The similarities of Guest house wiring and office wiring is that;
wiring system in Guest house and office are the same, that is to say, PVC plastic conduits shall be conceal or full conduiting wiring.
The same electrical accessories.
The same earth system.
The same lightening protection unit.
The same system of installing air conditions.
They standby generator in case public electricity switches off.
some Non Governmental organizations in South Sudan in their Guest houses and office have standby generator, solar energy system and public electricity, especially in juba such non Governmental organizations are carter center and save the children UK to mention but few.
Skill by skill in Electrical installation work in caravans.
Caravan electrical installation wiring system is different from Guest house and office electrical installation wiring but they have similarities in electrical accessories.
Why is it that caravan electrical installation is different from Guest house and office electrical installation wiring?
Caravan electrical installation wiring is mostly done in trucking, but the trucking is screwed on the surface of steel wall in internal of the caravan. But if the electrical installation wiring to be like conceal wiring or full conduit wiring, it will need to design (1x12)m timber or hard ply wood with insulator to be put along the steel wall of the caravan internally.
Conceal wiring system;- means that grooving and chasing builded wall from the marked position of switches, socket outlets, wall lighting brackets and main distribution switch while in the ceiling , the cables will be out side in the ceiling board.
While for full conducting;- means that grooving and chasing builded wall from the marked positions of switches, socket, wall lighting brackets and main distribution switch and in the ceiling, cables will be running into the conduits.
These wiring system takes a lot of money for buying timber, hard ply wood, wire nails, labour and also it takes time to one caravan.
Thus, surface wiring is preferable for caravans.
In caravans’ electrical accessories such as, ceiling fans rod type, cooker control unit, lighting protection unit, wall lighting point, decorated lighting point for sitting room, dinning room. These electrical accessories unsuitable in the caravans.
Why is it that electrical accessories such as ceiling fan rod type, cooker control unit, lighting protection unit, wall lighting point, decorated lighting points for sitting room and dinning room are not suitable for caravans?
Those mentioned electrical accessories are not suitable for caravans because of the following reasons;-
Caravans are portable buildings used for mostly on road constructions and emergency programmes like assisting in implementing agreement between two conflicted partners by world body organizations in the particular country. For example peace agreement between Sudan people's liberation army/movement and Sudan government to mention but few.
Second reason is that, the height of the caravan is approximately 2.5m or 2.7m which does not fit for electrical accessories such as ceiling fan rod type and decorated lighting points for sitting room and dinning wall brackets lighting points.
Since the height low, lightening protection unit shall not be in installed.
PVC flexible cable is mostly needed for wiring caravans .
Why is it preferable to use PVC flexible cable to the other cables like PVC flat gray cable and core cable?
It is preferable to use PVC flexible cable to flat gray cable and single core cable because, during transportation of caravan from one place another place in main cases it cuts those types of cables easily than flexible cable.
Also in caravan electrical installation wiring it does not need working drawing like Guest house and office electrical installation wiring.
Caravan electrical installation wiring does not need serious, electrical designing, drawings and planning on the ground plan of the caravan.
It does not need consultation on the type of roofing system and ceiling board.
Electrical earthing at the is must like in the Guest house and office. Its earthing is good to be connected with the earthing of the generator.
What are the similarities of electrical installation wiring in Guest houses, offices and caravans?
The similarities of electrical installation wiring in Guest houses, Offices and Caravans procedures in electrical wiring such as;-
Surveying the land scope of the site.
period given to complete the all job.
Electrical materials, tools, machine and other materials, tools to be used.
They have the same electrical accessories such as switches, socket outlets, ,lighting points like 4ft fluorescent lamps, Energy saviours and filament lamps.
They have the same air condition to be installed.
Number of workers needed to do the job.
The standby generators or two generators at the site.
After completion of electrical installation wiring in Guest house, Office and Caravans inspection and testing will also be carried.
In the next chapter of in-depth i am mostly going to explain how electrical installation wiring of Guest House, installation of split type of air condition and positioning of switches, socket, water heater switch, wall lighting points, main switch, wall fan.
