# relating resonance and power factor correction.

Discussion in 'General Electronics Chat' started by mentaaal, Apr 28, 2007.

1. ### mentaaal Thread Starter Senior Member

Oct 17, 2005
451
0
hey guys i was brusing up on some things using the literature here in allaboutcircuits. (fantastic texts by the way!) i was reading up on how one can improve power factor by adding more reactance that draws the same reactive power but of the opposite imaginary direction. like if you wanted to reduce inductive reactance you can add capacitance. thats fair enough and in doing this you reduce the amound of reactive power in the circuit reducing wasted work done.

So to achieve power correction you need to match the power of the reactive components in a tank circuit like fashion.. right? then in another situation for resonance to be achieved the reactive components have to be matched not by power but by reactance right? so does this mean that although a tank circuit will have infinte resistance (in an ideal situation) at its resonant frequency there will be still phase shifted current flowing through the circuit from the source to the tank circuit as the reactive components power "storage" and "supplies" arent the same? just a little confused when i related these too topics together. also as a matter of interest is there a situation possible where the reactive components are matched in reactance and power? or is that impossible as inductive reactance increased with frequency and the opposite for capacitance?

hope that made some sort of sence.

Cheers!

2. ### mentaaal Thread Starter Senior Member

Oct 17, 2005
451
0
ok i think i have seen the error of my musings....

in a resonant circuit the reactive components are matched together in reactance and all the power is transferred between them in a pendulum fashion.

the thing i am still unsure of is why when correcting power factor, the reactive components dont resonate. if the components were just reactive, the circuit would resonate as each leg of the tank circuit would be matched in reactance. so its because of the resistor in the circuit thats stopping it from occurring? even though with the resistor in the circuit each leg of the tank circuit will have the same impedance (i know this statement is incorrect as the impedance is technically not the same as the phase angles of them wont be 180 degrees out of phase but something else due to the resistor but i dont know how else to say it )

ah... i think it just dawned on me... the reason it wont resonate is because not all the power is being transferred from inductor to capacitor as the resistor is cntantly dissipating a portion of that energy.

i think its slowly starting to make sence to me but if anyone feels like adding to this post, your thoughts will be greatly appreciated.