show that power dissipated by a pure inductor exited by a sinusoidal voltage s

show that power dissipated by a pure inductor exited by a
sinusoidal voltage source v = vm sin wt is zero

Question Posted / mckash

1 Answers
4958 Views
I also Faced
E-Mail Answers

show that power dissipated by a pure inductor exited by a sinusoidal voltage source v = vm sin wt ..

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

Is This Answer Correct ?

3 Yes

0 No

Post New Answer

More Electrical Engineering Interview Questions

can any tell me how to do wiring connection in L&T 3ph 4wire E301 CT operated energy meter, what is P1,P2,P3,P0. M1,M2,M3, L1,L2,L3.

2 Answers Bhartiya International,

Can any body tell me about partial discharge test, and why it is necessary and its procedure

1 Answers

As we know induction squirrel cage motor torque Directly praprortinal to applied voltage in star connection & delta also. If I connect 55KW Motor to DOL starter in load condition does motor withstand the load & what will be the current withdrawn ? motor will not fail ?

0 Answers

is it possible to run a dc motor on ac supply with good performance.....?

3 Answers

what is the function of fire alarm system?

5 Answers

what is the use of pmg in exciter?

3 Answers

Why is transformer core is earthed

3 Answers

WHY FLEXI LINKS ARE USED INBETWEEN GENERATOR TERMINAL OUTPUT & BUS DUCT CONDUCTOR.

3 Answers

Do inductive loads have distorted current waveforms ?