Answer / ajay pilassery

P.f = cosø
bcz, p.f=true powr/ apparent powr;
i.e, true powr=VI Cosø &apprnt powr=VI. So, = VI COSø/VI.
I.e, p.f=cosø. Its only cosin angle

The product of VI COSØ is the true powr & is measured in watts(using wattmeters). So, the product VI is apprnt powr measured in volt-ampere., Like V*I in watts , (using voltmeter&ammeter)

Answer / brd ganesh

Let assume pi=0 cos(0)=1 it means there phase
angle(pi) is 0 then p=vicos
(pi)=vi*1=vi take a
sin instead of cos sin(0)=0 then p=visin(pi)=vi*0=0
that is why choose cos

The purpose of a choke is to provide a ?

1 Answers  

---

we r having 3 core 3 1/2, 4 core cables how we can know this cable has to be used for this purpose?

5 Answers  

---

Will a load of 15A work if we connect it between one phase and earth?

4 Answers  

---

why capacitance effect is predominant in underground cable transmission and inductance effect is predominant in over head line transmission?

0 Answers  

---

Which type of drive is advantageous AC or DC and why?

5 Answers  

---

---

when the control mechanism is present for an ammeter(1-10A) and 1A current is apllied what will be the reading of the meter?

2 Answers   GATE,

---

A 3PH MOTOR RUNNING IN NORMAL CONDITION AND ITS AMPERE ALSO UNDER ITS FULL LOAD CURRENT,ITS CABLE RATINGS ALSO HIGER THN ITS CAPACITY,BUT ITS CABLE GETTING ABNORMAL HEAT(NOT TOO HOT)WHY ITS GETTING HOT LIK THIS?

5 Answers  

---

Is there any thumb rule for cable selection for any current rating ?

1 Answers  

---

how to remover corona effect and hysteresis losses from contactor

0 Answers  

---

Does power factor vary with speed?If yes, how?If not, why?

4 Answers   Genco,

---

Which modulation has higher data rates a.fm b.am c.qam d.qpsk

1 Answers   NTDC,

---

like the transformer another electrical static device which operate on same priencipal?

13 Answers   Power Grid, Vishal Transformers,

---