Answer / gajanan

apperent power = voltage X current,
we can calculate apperent power by ammeter and voltmeter
reading but
real power = voltage X current X power factor

to measure real power we need wattmeter

Answer / nageshwaran.n

No doubt, we could use Voltmeter & Ammeter for calculating
Power but only Apparent Power that too at that instant.
Apparent power = voltage X current,

Actual RMS Power (real power) = voltage X current X power
factor

And to measure real power we need Wattmeter only.

Answer / smita

RIGHT POWER IS VOLTAGE X CURRENT BUT FROM THIS WE GET ONLY
APPERENT POWER,AND WE REQIRE REAL POWER I.E VOLTAGE X
CURRENT X POWE3R FACTOR AND FOR THAT WE REQUIRE WATTMETER

Answer / pillay

Yes as all have already said you dont need to use a watt meter
only if the circuit uses a Direct Current voltage and you can
calculate the power mentally by just looking at the voltmeter and ammeter.

Answer / sudheer

if we use more no of meters error is more

What are different types of control systems?

0 Answers  

what is calculation mathod/formaulla for deciding Size of busbar (Copper/ aluminum)for L.T. panel on Various Fault level like 50kA,25kA,10kA

0 Answers   Mega Power,

I have one ct of ratio 3000-2000/1 Amp its knee point voltage mentioned on name plate is 500-333/30mA-50mA at Vk/2. in secondary box there is three terminal named 1S1, 1S2, 1S3 then on which terminal obtained the knee point voltage ie 1S1-1S2 OR 1S1-1S3 & also specify the knee point voltage for the ratio 3000 from name plate.

0 Answers  

When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<

0 Answers   Lupin,

What should be the voltage between Neutral and Ground in secondary side of the step down transformer (230 V to 110 V) with no load condition?

0 Answers   Jindal,

why we not connect the 12 V batteries in parallel to get the more backup supply for an UPS ? wheter off line or on line UPS ?

2 Answers  

how can we select the appropriate VCB ?

0 Answers   Reliance,

We have 5 Distribution sections with variable loads&We have 3 Gensets(500kva,380kva&250kva) our total load is between 400kva to 600kva. so how could we connect 3gensets.

0 Answers  

pls define kvarh

2 Answers  

A powerplant has 8 gensets operating in grid parallel mode. In one genset sometimes there is pf variation and kvar variation. The plant operates in pf mode. When this variation is onbserved the load is stable, voltage is also stable, freq and genset speed is also stable. How will you check the functioning of pf card. What shall be the ideal output vdc of the pfc, from there it is input to AVR?

1 Answers  

what is ps impedance test

0 Answers  

I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?

0 Answers