Inspections & Testings

INTRODUCTION:
Inspection and testing play an important role in electrical wiring. It give details condition devices,if there is any burn out or loose of contact, then the necessary action can taken. Testing  is the way of identifying continuety in a electrical system or devices.

 Inspection is the checking of all control panel, bus bar and distribution fuse board to confirmed all the connection was made correctly to avoid risk of short circuit or potential contact of cable inspection is important because it can happen the short circuit or partial contact of terminal which lead to fire out break or not allowing power supply to be deliver to the load. During the inspection you may observe wrong connection or partial contact more especially neutral, which lead to absent of power supply.

TESTING: It consists of several testing equipment with the aim to confirm the electrical wiring of the build was ok and safe. One of most important of testing is continuity ,this will give assurance that all the cable have continuity as per as connection concern, it means if power supply deliver to the, no any abstract make sure , before carrying out  continuity the load is not connected to the supply. And also change tap change of your multi meter to continuity test.

 Calibration zeroing and care of testing device for calibration: is the system which allows user to select his desire quantity such as dc or ac and it can be current, voltage and resistance. This is important because you cannot use resistors Calibri for voltage.

Zeroing is the position instrument to zero position after taking reading. It makes next reading accurate and correct,

Care for instrument: if the testing instrument used dc source such as battery, you must care for the life time of battery, if it is weak, it can cause your testing instrument to give incorrect reading. Most modern testing instrument has battery indicate .if it is weak, this is great achievement. Now I will like to state different test to be carried out for proofer and stand electrical in building or industries.

A-Continuity of protective conductor

B-Continuity of ring find CCT conductor

C- Insulation resistance

D- Protection against resistance

E -Polarity

F- Earth electrode resistance.

G-Earth fault impedance

H-Prospective fault current

J-Functional testing

a- continuity of protective conductors: at the D.F.B joint together the phase conductor and its association C.P.C   using a 10 resistance ohm meter test between phase &circuit protective conductor (CPC) at all the outlet circuit.   

B- Continuity of ring final circuit conductors bases on the principle that resistance change with a change in length and cross-section area (CSA) we can use the following method:

Take two conductors TPN and ABC and take their resistance values figure 1.0

                                         

 

Then double them both over join the end TN and AC as follows:

T               P                        A

   

TEST PRODUCE IS AS FOLLOW:-

1-observe the resistance of both conductor and budge together phase and neutral at the midpoint socket (this corresponds to PB in figure 1.1) now take reading between complete phase $neutral ends in the D.F.B (point TN and AC in fig 1.1) record this as R2. For healthy ring circuit approximately half of R1 should be value of R2 should be quarter of R1.

Protection against direct contact by barriers or en closure: by using British standard finger you can connect in series with lamp and supply of not less than 40v and not greater than 50v the test finger is pushed into or behind the enclosure barrier and the lamp support not on. This can eliminate leakage current. Insulation  resistance.

An insulation resistance tester which is a high resistance ohmmeter, Care must be taking in carrying out this test.

Phase to earth procedure:

-ISOLATE the supply

-make sure the entire protective device is in place and all switch are off

-ling all pole of the supply together

-Test between the linked poles and earth as illustrated bellow:-

    

                               

                          



SINGLE PHASE       0.5M 2M

BETWEEN POLE:

-Isolation supply

-Make sure all protective devices are in place and all switch are closed

-Remove all bulbs equipment

-Test between poles

The test procedure was shown:-                                                          

                                      

                                    

POLARITY: this is important to confirmed all fuse and single pole device such as single –pole MCBS and switch are connected in the phase conductor only.

Functional Testing; prospective short-circuit current APSCC tester normally incorporated with a loop impedance tester is used for this. To conduct the test at the intake position problems or clip will be needed and hence great care needs to be taken when connecting to live terminal measurement are taken between P & N.

Residual current devices (RCD): Care must be taken when conducting above test because an intentional earth fault is produce in installation.

The test is as follows:

-Fester should be set to the RCD rating half the rated tripping current is passed through the device it should not trip

-Pass through full rated tripping current to the to the RCD it should within 200ms

-RCD has a test button which should be operated to confirm the accuracy of its tripping mechanism. It does check any part of the eating arrangement tester quarterly. 

OVER COMING CLIMATE CHANGE

INTRODUCTION:

According to the UNEP (United Nation Environment Programmed), Renewable energy sector is playing a vital role in providing clean energy sector, which show that the sector brought an estimated of 16% of global energy source Last year. Also it closes to produce 20% of the world’s electricity generation according to the report inaugurated by the renewable energy policy Network for the first 21^st century (REN21). ’’ The global performance of renewable energy despite headwinds has been a positive constant in turbulent times’’ Said Mohammad El-Ashry Chairman of REN21’s steering committee. China was the overall world’s largest investing country in renewable energy, at a record of $126.6 billion that is up to 31% on 2016. I hope African country will follow the same for overcoming lack of sufficient energy across the region.

Solar energy:

Defined as the radiant light and heat that originated from the Sun. It is a renewable energy that reduces climate change effect. Sunlight intensity differed from location to location on earth. This means careful survey and observations must put in place to have successful solar insulation , Check which purpose you want do with solar energy is electricity, thermal heating  or power load. Now, you will read about solar panel categories, their features and picturing view of some solar panel as we progress in this post.

What is Solar Panel?

Defined as the device that is used to accept the sun’s rays in direct current form (DC) and it can be converted to Alternating Current (AC) by the use of INVERTER and other devices, such as charge controller and battery bank, which I will discuss on them in subsequent post.

Solar panel divided into:

Active Type.

Passive Type.

Active Type: Is the solar panel mounted on space to collect sun light rays with the assistance of photo cells, it is energy Acceptor. Following is its pictorial view:

Passive Type:  This is designing a building with materials that have ability to harness thermal mass or light dispersing properties and designing spaces that allow natural fresh air to circulate. It is energy donor.

Solar panel consists of photo cell with either single junction or multi-junction. Their layers makes them differed. Single junction has one layer, while multi-layer have many layers.

Solar panel generations, their specification and efficiency, will be discuss soon.

First Generation:

Traditional Type.

Mono-crystalline solar panel Features:

-Is the most pure type.

-It has uniform dark look.

-It has circular edge.

-It has higher efficiency, due to the purest of Silicon compound.

-It reach 20% performance.

-It has higher power output.

-It has long life span.

-It has ability to withstand with effect of temperature.

-It has more expensive.

Poly-crystalline Solar panel Features:

-It has blue spackled view.

-Its angle not cute.

-It produced from melting raw silicon.

-It is faster and simple to produce.

-It has lower performance 15%.

-It has low price.

-It has transient life span due to the effect of temperature.

Second Generation:

Thin-film solar cell (TFSC) features:

-It used for photovoltaic power station.

-It used for small power station.

- It has expensive.

-It produces by placing single or more films of photovoltaic materials such as copper and cadmium.

-It is easy to manufacture.

-It is flexible.

-It is not affected by high temperature.

-It occupies large area of space.

-It has shorter life span.

Amorphous Silicon Solar Cell (A-Si):

-It can found in pocket calculator.

-It used triple layer technology.

-It has 7% efficiency rate.

-It has low cost.

THIRD GENERATION:

Cadmium Telluride Solar Cell (CDTE) Features:

-It has low price.

-It require least amount of water in production.

-It give carbon foot print as low as possible. But it may be toxic, if inhaled.

Concentrated PV Cell (CVP and HCPV):

-It was categorized under multi-junction type.

-It has 41% efficiency.

-It consists of curved mirror surfaces.

-It consists of lens and cooling systems.

-It contained tracker that track the high efficiency Angle of sun rays.

Solar energy consist of different stages before it reach to consumer unit.

Firstly, Solar panel which accepts sun rays using photo cell in DC form. At this level, it can be use to power DC Appliances only. But if you want power AC appliances, there is additional devices such as Battery bank, which serve as storage component at the night time. Also Charge Controller must be install for the purpose of controlling the battery charge, if the battery charge full, the charge controller will cut-off the supply to the battery this make battery to work longer.

Also, there is inverter which inverts DC V TO AC V for the appliances that use AC Current. It must load with full capacity, this is contrary to the Generator because loading it full or overload can spoil it. But Inverter need to be loads all. This means, you must make sure you installed inverter that can take all the require load in your place.

Consulted Sources:

Askari Mohamad Bagher.

Mirzei Mohmoud Abadi Yahid.

Mirhabibi Mohsen.

My little knowledge I thought at school by:

Engr. Dobi Illo @ WUFP B/K.

http://news.un.org

Computer RAM

INTRODUCTION

RAM is the acronym of Random Access Memory that computer uses to run its operation and other application you lunched or opened. Also can be defined as volatile computer memory that store and provide data to the user temporary, it lost all data if power cutoff. Computer system has different size, such as desktop, laptop and tablet. Therefore RAM also has different types, size and terminologies as follows:

Terminologies in RAM:

-Pins: Means number of contact contained in RAM, it can also refer as lead.

-Bus: is a portion of area that transfer large numbers of signals within different integrated circuits. For instant FSB( Front Side Bus) it transfer data from CPU to the memory controller and other destinations.

Subgroup of buses:

-Memory bus which links the memory controller.

-Address bus contained in RAM.

-Data bus.

-Command bus.

Parity:

Is a section of an error checking process that can be used to verify the integrity of information stored in RAM? It has “parity bit” that is even parity and odd parity.

ECC: Error correction code RAM is the additional data storage for checksum bits to permit correction of errors. The memory controller on motherboard must be compatible with ECC.  

SPD (Serial Presence Detect- Circuit (an EEPROM) :

EEPROM is the Acronym of Electrically Erasable Programmable Read only memory that built inside memory module. It has responsibility of sending information to the BIOS, then to the memory controller to highlight it what category and how much memory is present.

Heat Spreader:

This is heat sink, it disperse heat developed by RAM as a result energy transfer. It cool the RAM. It also gives room for the manufacturer to design their logs on it.

Virtual memory:

Is a RAM that is simulated by the system when the space full in real memory modules. It is actually space on the hard Drive, this made it slower in terms of accessing.

Latency: This refers to delay interval of RAM.

Bank: is a group of memory chips. That joint together to supply enough data bits to be equal CPU data bus(32 bit wide).

Rank: This refers to raw of memory chips. It can be double rank. Which is very common presently?

Cache memory: It is term used to identify a number of distinct functions inside computer system. Its function to improve performance of system.

Features of Cache memory:

-It is the separate store of SRAM used by CPU to store the most frequently used information.

-It can be access very fast than RAM itself.

-It consists of many levels of cache, there closeness to CPU, determine its high speed of access. For instant Level 1 Cache is normally part of CPU chip itself. While Level 2 and Level 3 are external usually on motherboard.

Types of RAM:

-SIMM (Single inline memory module) :

It contained obsolete power and data contacts on only one side of the board. Is the type of memory sticks with 30pins.

-DRAM (Dynamic Random Access Memory): It required refreshing constantly and it used in PC.

Features:

-it has low cost of production.

-It has higher memory capacity.

-It has lower access speed.

-It consume low power rate.

It found in video graphic memory.

-It used in system memory.

Types DRAM:

-FP (Fast page RAM): It permit multiple access to a memory location and not required identification of the address.

-EDO (Extended Data Output RAM): it has approximately 10% increase over fast page. It also called Hyper page Mode (HPM).

-SRAM (Static Random Access Memory):

 This contrary to DRAM, because it can retain data without refreshing. It is faster and it has larger capacity size with more expensive.

Features:

-Lower power consumption.

-It is used in CPU cache, such as Level 1.

-It is used in hard drive buffer.

-It is used in Digital Analog Converter (DAC) and video cards.

-it can found in printer.

-It is used in routers and LCD Screen.

-It is used in Digital Cameras.

-SDRAM (Single data-rate Synchronous Dynamic RAM):  It is 64bits and it has 168pins.

Features:

-It can process Read AND Write instruction per clock circles, on which enhance transfer performance rates of CPU.

-It has different memory bank.

-It has ability to receive fresh instruction before concluding executing current one.

-It in the market competition since 1993 to date.

-RAMBUS: A revolutionary memory technology developed by RAMBUS inc as a video memory and designed for use in personal computers (PC) with Intel processors.

-RAM (Rambus Inline Memory Module): It has 184pins modules.

-C-RIMM The continuity module need to fill empty memory slot in the RAMBUS system.

DDR (Double data Rate Memory): It has capability to do double read and write instruction per clock circle. It is used in video game. It consists of 184pins.

-SODIMM: Is a small outline version of DIMM. It has 144 or 200pins. It found in laptops computer.

-SORIMM: Is a small outline versions of RIMM, it consists of 144 or 200pins. It also found in Laptops computer.

-DDR2 (Double Data Rate 2 Memory): It operates twice the clock rate (2004-2007), but it not compatible with DDR.

-DCM (Dual Channel Memory): is resembled DDR but their motherboard differed.

RAM Module size is always double.

Graphics Double Data Rate Synchronous Dynamic RAM (GDDR SDRAM): This type of was designed only for video graphics with a dedicated graphics processing unit (GPU), on video card, it can be 720p OR 1080p.

ELECTROSTATIC DISCHARGE PRECAUTIONS:

Did you ever try to touch metal door or your brother body and feel shock? If yes, nothing than Electrostatic electricity. It has the capability of erasing stored data in a device that is why it is necessary to take measures during repairs of any electronic device as follows:

-Make sure you wearer a static strap, that will attach to the chassis and worn on your wrist during the repairs work.

-Keep away any mobile phone near computer system.

-Use discharge static hand gloves.

-By using ESD Mat.

Consulted Professional:

www.bleepingcomputer.com

www.computerhope.com