Showing posts from 2017

Working Principle of Smoke Detector

Basic Working Principle of Ionized and Photoelectric Smoke Detectors for Fire Alarm SystemSmoke Detector is the main sensing device in Fire Alarm System. To understand the basic working principle of smoke detector, we should remember Ionization and Photoelectricstructure, smoke detectors are manufactured basically based on these two principle. According to these rules there are mainly two basic types of Smoke Detector, you will find in the market.
Ionization Smoke DetectorPhotoelectric Smoke DetectorHow Ionization Smoke Detector Work
In ionized smoke detector, basically two positive and negative charged plates are consisted in an ionization chamber wherein a radioactive material like americium 241 is placed, shown in figure-1.1.
Air molecules collide with radioactive particles and extricate their electrons. Since the molecules lose electrons, they become positively charged ions; the same as other molecules gain electrons, they become negatively charged ions. Equal numbers of positive an…


Power Cables Termination and Sealing End Requirements The servicer should terminate and connect up the power cables in accordance with diagrams or details approved by the employer Engineer. Considering the followings requirements, power cable along with others controlling and communication cable sealing end should be terminate in an adequate manner.

For control wiring, the cable tails shall be so bound that each wire may be traced back to its associated cable without any difficulty; cores in twisted pairs or groups shall be kept together; nay spare cores shall be numbered and terminated on spare terminals. The servicer is to be responsible for the correct phase rotation and connections in accordance with information approved by the Employer. Particular care is to be taken in the case of these cables, where sub-sequent correction may be difficult. Phase tests should be carried out by the servicer to the satisfaction of conformation. Necessary equipment may arrange to carry out these tes…

মানব শরীর ভবিষ্যতের পাওয়ার হাউজ

মানব শরীর হতে যাচ্ছে বিদ্যুৎ  তৈরির পাওয়ার হাউজ। কথাটি শুনতে কেমন সিনেমা-টিক সিনেমা-টিক মনে হলেও বিজ্ঞানীরা কিন্তু  বেশ সিরিয়াসলিই চিন্তা করতে শুরু  করছেন। শরীরের তাপ, নরাচড়া, বিপাক, কম্পন এ সব থেকে ক্ষুদ্র আকারে শক্তি উৎপন্ন করা এক অর্থে বিরোপ জলবায়ু পরিবর্তনের যুগে ভাল খবরই বটে।

বিদ্যুৎ  কি থেকে তৈরি হয়? কি ভাবে তৈরি হয়? সহজ উত্তর বিদ্যুৎ তৈরি করতে নির্দিষ্ট কোন কাঁচামালের প্রয়োজন হয় না। এটা শুধু এক প্রকার শক্তিকে অন্য প্রকারে রূপান্তর করে মাত্র। এই রূপান্তরিত শক্তির প্রবাহই হল বিদ্যুৎ। আর এই রূপান্তর বিভিন্ন উপায়ে হতে পারে যেমন- তাপ, চাপ, আলো, কম্পন, ঘূর্ণন, পারমানবিক বা রাসায়নিক বিক্রিয়া ইত্যাদি। বিদ্যুৎ  তৈরির অধিকাংশ উৎসই মানব শরীরে উপস্থিত। 

কিন্তু প্রশ্ন বিদ্যুৎ তৈরির এত এত উৎস থাকতে কেন এই ক্ষুদ্র চিন্তা? এই ক্ষুদ্র বিদ্যুৎ আমাদের কি কাজে আসতে পারে। কিন্তু বিজ্ঞানীরা এটাকে ক্ষুদ্র ভাবছেন না। আর এর প্রয়োজনও কম মনে করেন না।আসলে যেকোনো কিছুর প্রয়োজনীয়তা বা গুরুত্ব  ক্ষুদ্র বা বৃহৎ আকার বা পরিমাণের উপর নর্ভির করে না। প্রাপ্যতার নির্দিষ্ট   স্থান, কাল ও পরিমাণই মুখ্য ব…


What Is IP- Ingress Protection RatingsWe are familiar with some protection symbol in our appliances and equipment as IP- like IP22, IP56, and IP64 so and so. But to most of us it’s not clear, what bearing the meaning is. Most commonly, we feel happy and secured if someone ensure it is waterproof. Similarly we also familiar with Water-tight, Rain-tight, Rain-proof, Dust-tight & Drip-tight etc. that makes our sense easily. IP is shorten of Ingress Protection or ingress protection rating, sometime says International Protection rating. The letters IP contains two digit numerical number after the letters IP, sometimes one additional letter also uses to describe protection against mechanical impacts. IP or Ingress protection mainly uses for electrical enclosure or cabinet where electrical or electronic equipment are associated to prevent electrical shock to equipment users and save the equipment from the environment. IP Ingress Protection DegreesEach equipment has its own requirements to …

Operation & Installation Guide For Scroll Compressor, Frequency Converter & Temperature Controller

This operation, installation & maintenance complete guide for Danfoss refrigeration and air-conditioning main equipment such scroll compressor, frequency converter and temperature controller EKC204A & EKC102. These refrigeration control system manual will make happy to any technician or operation and maintenance engineer who working with heating ventilating and air conditioning (HVAC) system.
Scroll Compressor GuideQuick reference of Danfoss compressor manual will cover working principle of scroll compressor and Danfoss full  product range with performance data.
Nomenclature: Danfoss scroll compressor nomenclature will help to quick-find the compressor technical basic data-   lubricant & refrigerant family, nominal capacity, operating voltage &  product version, etc. as described below:

You can download the full Danfoss scroll compressor SM-SY-SZ, R22-R134a-R407C quick reference manual in pdf file just clicking download link below: 
DOWNLOAD .pdf  scroll compressor full g…

Fault Location Overview On HVAC Compressor-Danfoss

This is an intelligent technique of an HVAC professional just beginning systematic fault locating, cutting off the power supply  for at least 5 minutes which will ensure that the PTC starting device has reset and cooled off to ready for next new start. The first minutes of power cut-off  pull down the appliance with cold compressor and lead to an interlocking situation.

In this article will helpful you who are seeking for understanding the service network for household appliances and similar.

This focuses on mainly PL, TL, NL and FR compressors for 220-240V. For detailed information on compressors download the full pdf version file from the below link; from where you can learn details about compressors types- PL, TL, NL, FR and partly SC are equipped with a PTC starting device or a relay and start capacitor.

This guide discussed the following fault location procedure for HVAC Compressor system step-by-step that will very helpful for a technician.
Fault location; Electrical…

Trouble Shooting a Faulty Refrigeration Circuit-Danfoss

How to Troubleshoot HVAC Faulty Refrigeration Circuit Smart troubleshooting of HVAC problems and malfunctions is a technique how a HVAC technician thinks very sharply and shoot skilled way. Quick trouble shoot depends on fault finding techniques rather than the difficulty the fault. Sometimes very simple problem kills a long-span of technician time, reversely tactful technician solves the critical malfunction very quickly.  
Today, we will focus our short troubleshooting discussion on some common technique to find the faulty part on HVAC refrigeration circuit system
The total Heating Ventilating & Air Conditioning system is a vast system, and it contains various types lots of equipment. An HVAC system consists of compressors, motors, furnaces, cooling systems, air conditioner, air handling systems, ductwork systems, heating systems, humidity controlling systems, fan connected networks, different types of controllers and vast electrical & mechanical systems.
How Think to Trou…

HVAC Troubleshooting And Measuring Instrument: DANFOSS

In HVAC Engineering Troubleshooting is very important to keep the equipment alive to give a comfortable life at home and a productive hour in works. To become a good troubleshooter proper measuring instruments are very essential. Danfoss offering the following measuring instrument for troubleshooting the HVAC equipment. Measuring Instruments Instruments for fault locationClassification of instrumentsUncertainty ResolutionReproducibilityTemperature stability Electronic instrumentsCheck and adjustmentAdjustment and calibrationPressure gaugesService pressure gaugesVacuum gaugesThermometer Hygrometer
To ensure a better service for refrigeration system- a fault locate as early before it reach at severe condition or shutdown the system and servicing the fault parts promptly- a reliable tools is required. 

Understanding deeply and keeping study more, download the HVAC Troubleshooting And Measuring Instrument guide for DANFOSS in pdf  file from below link. DANFOSS guideDOWNLOAD .pdf

Design Guide for Underground Transmission Line

Design Guide for Electrical Energy Transmission in Underground Cable Network Voltage level of transmission line network is the key considering design guide factor for bouth overhead transmission system and underground cable transmission system. Schematic line diagramin below , the specific voltage level guide are used for conventional overhead transmission and new concept underground transmission network system for- Power Generation; Bulk Transmission; Sub-Transmission; & Distribution System. What The Distribution Voltage Level Is?In electrical power transmission and distribution system, voltage levels are divided into different category considering the equipment operating capability, such as- Low Voltage (LV)              - up to 1000Volt; Medium Voltage (MV)       - 1000 Volt ~ 35 kilo Volt; High Voltage (HV)            - 35kilo Volt ~ 230 kilo Volt; Extra High Voltage (EHV)  - above 230 kilo Volt; & Ultra High Voltage (UHV)  - above 800 kilo Volt. Also, very safe low voltage like less…


Resisting severe or extreme  temperature like very hot or very cold is very challenging for electrical energy transmission power cable. But cable manufacturer are continuously changing their gear to design a upper product to take a new challenge for severe hot and cold temperature resistance along with mechanical and chemical loading.

Power Cables Can Work in Extreme High Temperature Cable manufacturers claim that they use some intelligent materials to combat temperature extremes like + 90°C to -180°C. Cable having the aid of pure nickel conductors can work in as high as 500°C without any problem. Quartz and silica taping makes electric cables flame-resistant and heat-resistant to over 1100°C.
Power Cables Can Work in Blaze and Self-ExtinguishDuring high flame, cable can protect itself using self-extinguishing technique. Doping chlorine, fluorine and bromine cable become a flame retardants and self-extinguish. Using some silicon-based material, metal clad or ceramicized cable even can …

Safety Clearance to Exposed Live Conductors

Working Safety Clearance and Phase Gap between Exposed Live Conductor Herein this article we will focus on “safety clearance to live bare live conductors during working in electrical power distribution substations or switching stations” and “phase gap or safety clearance to electrical energy transmitting energized conductors between others power conductors, communication conductors or transportation navigation system” to ensure safety for human and property, as well as operate a proficient electrical energy network system. Safety Clearance during Works in SubstationsLine crews often work in a substations or switching stations where all the equipment and conductors are not possible to be dead; but possible to ensure minimum safe distance for the working section from the exposed live section following as below: 1.Dead or working section should be identified clearly and barricaded appropriate barrier-rope; 2.Electrical live or non-working portion must be defined with appropriate signs; 3.Rec…


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