Answer / quratulain javaid

Derating is design process that can make significant contribution to reliability.The reliability of electrical/electronic component decrease when they operate at high stress level.These stresses are primarily temperature, voltage, current & power dissipation

In electrical derating means lowering the electrical capabilityof electrical apparatus'.In electronics derating is a operation of a device at less than its rated maximum power in order to prolong life.So it is necessary to know the derating factor for each component type related to one critical condition to run/operate in safe level.

1]how the voltages and frequency are achieved on ships. 2]how does the line and phase voltages are related on ships.

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what is the benefit of floating our DC source? if i have two floating DC source of which 1 has a ref voltage of -21VDC and the other of -18VDC. can it be connected in parallel to share a common ref voltage? if not, how do i make both sources to be of common ref voltage? tks

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electrical ques

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Usually in the L & T make MCC feeders' power circuit,we have BMR after the MAIN CONTACTOR.,can we interchange their position, keeping the control logic same???

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why can we use cosine wave instead of sine in ac supply as both have same rms vale and ripple factor

0 Answers   Indcoil Transformers, Power Grid,

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why free wheeling diode is connected across inductive load

16 Answers   NTPC, Omaxe, Wipro,

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how does the power is travelled in conductor

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We have 11kV/110V three phase indoor potential transformer in 66/11kV Sub-station, where the failure of PT is frequently happening and the rating of the PT is 0.2 class accuracy, with primary star and seconday (two cores) star connected. Some experts has suggested to not to connect the PT Primary neutral to the ground because when transformer neutal NCT connection is loose; the faulty current will flow through the PT primary neutral, resulting into failure of PT. My question is: Is it necessary to remove the primary neutral connection of the PT from ground? if not, what would be the reason for failure of PT. Please guide me.

2 Answers   KPTCL,

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Why capacitor is blow when I am starting motor ?

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what is the different ratings of ACB/VCB/SF6 which is used at HT side

3 Answers   Hosco,

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power formula

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How the size of transformer decreases if we increases the frequency?

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