Answer / sarmadahmed

Let Vmcos(wt+X) be the voltage and Imcos(wt+Y) be the current through the inductor.
Now the power is given by
P=V*I=VmImcos(wt+X)cos(wt+Y)
By using a trigonometric identity:
P= 0.5 * VmIm * cos(X-Y) + 0.5 * VmIm * cos(2wt+X+Y)
This expression has 2 terms which both must be zero.
The first term is a constant (independent of time) but notice that in an inductor Voltage leads Current by 90 degrees so X-Y = 90 and cos(90) = 0 so first term is zero.
Now for average power integrate the above expression for a cycle and divide it by time period, since integral of every sinusoid for a complete cycle is zero the next term will essentially be zero too.

So P = 0 for an inductor.

Email me if you still have any doubt or query.
sarmadahmed@live.com

For 160kw motor what size of cable and material is needed.?

1 Answers  

---

What is d diff. btw MCB & MCCB???

1 Answers   Emerson,

---

WANTCONTACT NUMBER & EMAIL/ WEBSITE TO CONTACT THE SECRETARY,MADHYA PRADESH LICENSING BOARD(ELECTRICAL),K- BLOCK,3RD FLOOR,SATPOODA BHAWAN,BHOPAL

0 Answers  

---

i am going to correct power factor of 1600kw induction motor,when i calculate capacitance of capacitor it is three time more in star connection than delta. if motor is star connected which connection i shall adopt for capacitors and reason for adopt this connection

0 Answers  

---

What is VSCF windelectrical system?

0 Answers  

---

what is the minimum voltage require to injure our body?

4 Answers  

---

Should transformer earthing pit, to be connect to earthing mat in Substation

4 Answers  

---

What happens on the secondary of a 33kV/11kV when one phase of the primary fuse blows?

3 Answers  

---

why three phase system is not preferred in aircrafts power cckts if yes than explain reasons?

3 Answers  

---

WHAT ARE THE EFFECTS OF SERIES RESONANCE AND PARALLEL RESONANCE ON THE CIRCUITS PARAMETERS?

0 Answers  

---

How to calculate or testing the KW in generator

1 Answers  

---

how to calculate the power loss of cable?

1 Answers  

---