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Indoor Transformer Installations

By Nirmal -
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Indoor 1. Only dry type transformer shall be installed inside residential./ commercial buildings. While using oil filled transformers certain steps are there to be followed: a. it must be installed OUTDOOR only. b.Easy access of fire station vehichles. c.the transformer room/building must be 1.5 mtr away from the residence/commercial building d. the substation must be weather proof, walls must have minimum thickness of 230mm of thick RCC, Fire resistant wall must be there. e. outside corporation area minimum distance between transformer and substation must be 6m. 2. dry type transformer must be installed above ground floor. 3.ABSF/VCB ust be provided at primary side. 4. Minimum cable size at primary must be 150sq.mm XLPE (aluminium) or 70 sq.mm XLPE (Aluminium) if backup fuse is provided. 5.Oil filled TRFR must be segregated from HT and MV switchgear. 6.oil drainage facility/soak pits must be provided for oil filled transformers if oil quantity is above 2000 litres.
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Diffrent Types of Transformer

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Step up & Step Down Single Phase & three phase Power transdormer & distribution transformer Indoor & Outdoor transformer Oil immersed & Dry type transformer
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Night Vision

By Nirmal -
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Night Vision technologies is a kind of techniques of image conversion, image intensification and thermal imaging. Each has distinct characteristics and capabilities. The current image intensification technology utilizing photocathodes, phosphor screens and microchannel plates -- illustratres the technology of light amplification and image resolution. Night vision technology, by definition, literally allows one to see in the dark. Originally developed for military use, it has provided the United States with a strategic military advantage, the value of which can be measured in lives. Federal and state agencies now routinely utilize the technology for site security, surveillance as well as search and rescue. Night vision equipment has evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology 
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BIOMETRICS

By Nirmal -
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Over the last few years a new area of engineering science has been established whose products are likely to create a large market in the near future. It has been called ''biometrics". The pioneers of this new domain intend to construct devices which would allow identification of a person on the basis of his/her ''biological'' characteristics: voice, dynamics of movements, features of face and other parts of the body, retina or iris pattern. Nature has made human beings with different characteristics which may vary from one person to another. This property is made use of by Biometric technology to distinctly identify each person Biometric system is essentially a pattern recognition system which recognizes a user by determining the authenticity of a specific physiological or behavioral characteristic possessed by the user. Several important issues must be considered in designing a practical biometric system. First, a user must be enrolled in the system so tha
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When a 3 phase system is balanced, what will be the current in the neutral wire ?

By Nirmal -
Neutral is the point at which all the three phase’s current meets and the algebraic sum of current becomes zero in case of “Balanced Load Condition”. I = I1 + I2 + I3 = 0 When ALL phase has balanced load, neutral should be ZERO volt in respect to earth. Be careful the word “Balanced”, which means, if there is an unbalanced phased (due to load), the neutral will no longer be ZERO volt in respect to earth. When there is more than ZERO volt between neutral and earth, then there will be current flow through these 2 points (Leakage Current). Even for most of the time, neutral and earth has ZERO volt between them; they should never be connected together or be used interchangeably. Neutral: Return path of current flow in order to make a closed circuit [Return Path Conductor]. Earth: Path for Leakage current [Short Circuit / Fault Current / Crack in Insulation] in the circuit to protect Human & Equipment Safety.
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The Difference between single phase and three phase system?

By Nirmal -
Phase is the differnce between waves, through which the current flows. 1 phase consists of 3 wires , 1 phase 1 neutral and 1 stay wire. 3 phase consists of 5 wires , 3 phases(R, Y, B), 1 neutral and 1 stay wire. In most of the transformers 3 phases are mostly used except the road side transformers because the voltage of 3 phase is 440v. In domestic appliances 1 phase is used because the voltage required is 230v 1. Single phase voltage is compare then three phase voltage is very low for ex- 1 phase 240v < 3 phase 440v. 2. Three phase can make rotating magnatic field but single phase can not make rotating magnatic field. 3. In three phase is phase sequence but single phase is not phase sequence.
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kirchhoff's voltage law

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The second of Kirchhoff’s Law states that the algebraic sum of voltages around a closed circuit loop is zero . There’s the phrase ‘algebraic sum’ again, so we must recognise that the direction of voltages matters when using Kirchhoff’s Voltage Law.
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