## Current and ohm’s law

1. Drift velocity of electrons Electrons move in the conductor randomly when no voltage applied to it and so average velocity is zero. When a voltage applied to the conductor,…

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## Resistor Transistor Logic(RTL)

Now it is not used anywhere in the design of integrated circuits. In this type of ICs , only transistors and resistors are used. The RTL circuits basically performs the…

## What is the use of silica gel/breather in transformer

Pic: A transparent box containing silica gel crystals You have seen this type of transparent box with blue crystals like substance inside. These blue crystals are silica gel. So what…

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## Difference between Live tank and dead tank current transformer

Before we start, lets go back to CT basics, what a CT does , obviously a 2000/1 amp delivers 1 amp at secondary when 2000 amp is flowing or 0.5…

## Terms related to CT/PT(Burden, Accuracy Class, Instrument Safety factor, knee point voltage etc.)

There are many terms we come across when we read about current transformer(CT) and Potential transformer(PT) or voltage transformer(VT) /capacitive voltage transformer( CVT). below are meaning of these terms. CT/PT…

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## SF6 Gas circuit breaker: Construction, Working and Advantages

SF6 gas is an inert gas with dielectric strength and arc-extinguishing qualities. In SF6 breakers, the rate of rise of dielectric strength is very high and the time constant is…

## What is CVT(Capacitive Voltage Transformer)

The capacitive-coupled potential transformer (CCPT) or Capacitive Voltage Transformer is a Voltage Transformer with a capacitive circuit as shown in the figure below. The two Capacitor C1 and C2 here…

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## Dissolved gas analysis (DGA) of Transformer Oil

When a oil immersed transformer is subjected to internal faults, than due to short circuit flowing through transformer windings, the temperature of windings rises, this give rise to rise in…

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## Capability curves of Synchronous Generator

Capability curves are a plot of apparent power capability (MVA), at rated voltage, using active power (MW) and reactive power (MVAR) as the two principle axis. Circumferences drawn with their…

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## Performance curves or operating characteristics of an Induction Motor

Performance curves means when motor performance is shown as a graph from starting of the motor to running. Generally variation of following parameters are noted at various loading of the…

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## Crawling and Cogging in induction motor

Both crawling and cogging effect is only observed in squirrel cage induction motor as in wound rotor inductor motor, this effect is not observed as toque is very large. Crawling:…

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## Pre-commissioning checks or testing on circuit breaker

Circuit breakers are installed indoor and outdoor. indoor in the panels , and outdoor in the panels or standalone. Circuit breaker can be air circuit breaker(ACB) or SF6 circuit breaker…

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## What is synchronous condensor and why it is used

Synchronous condensor is just a synchronous motor without any load , but with over excitation. Generally it is used in receiving grid electric substations to improve power factor. The synchronous…

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## Different Methods for drying out of Motors

When the motor becomes wet due to being flooded or climatic conditions or when the motor rewinding is done. It shows very low value of insulation resistance. The low value…

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## What is a chiller

Chiller is a equipment used for air conditioning purposes. Basically it produces hot or cold water to warm or cool the air for space heating and cooling purpose. Chiller has…

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## What is full form of MCB, MPCB, ELCB, MCCB,RCCB, ACB and VCB.

MCB : Miniature Circuit Breaker MPCB: Motor Protection Circuit Breaker ELCB: Earth Leakage Circuit Breaker MCCB: Moulded case Circuit Breaker RCCB : Residual Current Circuit breaker ACB : Air Circuit…

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## Construction of a LED bulb/lamp

A conventional LED lamp has 6 main components: 1. Base: It serves as the entry electrical power. There are multiple types based on the design and diameter of the base.…

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## Sizing of capacitor for power factor correction of system

Consider a system having following loads , we want to improve the system power factor to 0.95 EquipmentOutput KWEfficiencyLoad KWPower factorKVAMotor A300.933.30.841.7Motor B900.9297.80.85115Lighting200.8523.50.9525Heaters10 10110Total150 164.6 191.7 Total load in KW = 164.6 And…

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Diesel Generator

## Sizing calculation of a Diesel Generator (DG) set :

Consider the following loads, a DG set is required to run these loads. 2 nos 150 KW, 415 volt motors with start/delta starter2 nos 150 KW 415 volt motors with…

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## UPS Sizing calculation

UPS required for  the load of 55 KW at 0.7 power factor or 78.5 KVA Inverter output = 55 KW Inverter input(considering 94 % inverter efficiency) = 55/0.94= 58.5 KW…