Here's a drawing of a simple AC line filter, which can be used to either drain excessive Harmonics, or to try to get rid of noise [EMI/RFI,etc.].
It's kind of like two "PI" filters stacked on each other
This one has a bandwidth of 48 to 440 Hz - where it should crossover. I'll figure the Fc and Fres for it, then post later.
The 465 microHenry Inductors [chokes, or coils "L"], can pass upto 6 amps before entering the point of no return
[AKA getting close to letting the smoke out].
The input section of Capacitors creates the first part of the Low Pass filter, by allowing higher frequencies to pass through the Capacitor [the Resonance of the Capacitor as compared to the Resonance of the Inductors will pass higher frequencies easier - the Inductors will allow lower frequencies to pass easier].
The final section of Capacitors will allow any high frequencies that passed thru the Inductors, to be "Shunted to Ground" via the ground center tap point between the two Capacitors in the output section.
This can help to drive Harmonic currents to ground, rather than backfeed thru the AC power system - which is why a Dedicated and Isolated grounding conductor should be used [to keep the shunted currents from flowing all around the AC power system's grounding conductors, conduits, etc.]
Dedicated IGs should be terminated at the grounding electrode's connection to the grounded conductor for the system feeding it [main service, or if SDS, the transformer].
[This message has been edited by Webmaster (edited 06-18-2001).]