Answer / santhosh

Power is classified in to three types: True power(KW),
Active Power(KVA) and Reactive Power(KVAR).

KW = KVA*Cos pi
KVAR = KVA*Sin pi.

Generally we consider Cos pi as 0.9.
Hence from above formula we can see that as KVAR increase
Cos pi decrease. That is as reactive power increases the
the power factor will decrease and which ultimately effects
the total electrical system.

Therefore to neutralse the reactive power we use capacitors
so that the power factor is maintained at 0.9.

Answer / shyamkr

reactive power is that component of apparent power which
moves to and fro between electrical source and energy
storing element.it doesn't do any useful work.it always
comes into action when there is reactive or energy storing
element.
when a load of low power factor is used it draws a large
amount of reactive power due to which the current in the
circuit increases which causes more losses in the circuit.

Answer / soumen koley

if there is any angle formed b/w voltage & current. then the
sine of the angle produce reactive power multiplying with
apparent power.
Q=VISin(phase difference)
any motor has need reactive power for magnetizing. with out
it motor can not run.so it is good.
the reactive power also reduce the power factor. as a
result the active power becomes poor. the line current
increases with the decrease of voltage.so it is also bad.

Answer / n.krishnaswamy

When power factor decreases more power is drawn and energy charges will increase.So power factor is to maintained near to unity.In our state,for an HT consumer, if power factor is less than 0.9 there will be exorbitant fine.I f it is maintained above 0.95,we will get good incentive.In one of my project, the total energy cost is Rs.17 lakhs. Since the power factor is maintained 0.99, the incentive is Rs.83000/-

Answer / ravindra

reactive power is only a expression of power factor by the
point of view of power system. as cos x increas means sin
x will decreas . so reactive power provide same information
as cos x. the importance of reactive power comes when in
power system analysis done with p.f expression cos , the
equations
of buses becomes too hard to calculate .so insted of it "q"
expression is used which easy the complex problem. and q can
t be a power bcoz its unit is kvars. its like a jinda lass

pls send link about servo motor

3 Answers  

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234 MVA Generator 3 phase Short circuit current Values required? Gen set Rating-234 MVA, Gen Voltage-18kv, PF;0.8, Xdv:23.5 %, Transformer Rating-18/380KV, 680MVA,Yndd1 two winding, Step up TR, ZT:35.50 %,X/R 4.33 Gen CB Position, CB open ,Disconnected open, Generator Running Voltage 18 Kv, Bi mistakes generator side earth switch Closed during that time short circuit current level in 3 Phase required, and how to test on site 234MVA Generator Short circuit current,

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Show Details FROM:Muhammed Ikram TO:qa@allinterview.com Message flagged Saturday, June 4, 2011 10:07 PMMessage bodyHello all, i want to ask a question to all of you that what is VMM (voltage monitoring module )? how it work,s? i heard somewhere that it compare 1 phase voltage to other phase voltage. but there is also some setting on it. how to set it,s setting. please tell me briefly. Thank,s and Regard,s. Muhammed Ikram.

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how to carried out tan delta test in 11 KV alternator ?

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Hi,, Just I want ask, if the power factor decrease what happen in voltage regulation? Thanks..

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