Part 2: For greatest effectiveness, ferrite cores must be installed on the DC and AC conductors as close to the inverter as possible.
Capacitors installed across the AC conductors must be of appropriate capacitance, voltage, and ratings for this application, and must be UL-recognized for such service. RFI filtering is a bit like filtering of internal combustion vehicle exhaust. You can reduce the unwanted/undesired aspects - but not eliminate them. Dan --- On Thu, 6/24/10, Exeltech <[email protected]> wrote: > From: Exeltech <[email protected]> > Subject: Re: [RE-wrenches] AM noise on batteryless inverters > To: "RE-wrenches" <[email protected]> > Date: Thursday, June 24, 2010, 11:34 AM > RFI (radio frequency interference) > from inverters > is a fact of life. This is especially true at > lower frequencies, such as for AM radio. > > There isn't a cure-all. Each make and model of > inverter will differ in the amount of interference > it generates. Steps to reduce the problem also > differ. > > Ferrite cores (mentioned below) may help. These > need to be installed around DC and AC leads. > Multiple cores on each DC leg are almost always > required due to the very low impedance presented > by the DC input side of the inverters. Looping > AC conductors multiple times through a large > ferrite core will also be helpful. > > Bypass capacitors are also often beneficial when > they're connected to the conductors on the battery > and load side of the ferrite cores. > > Ensure all chassis screws are clean and tight. > Earth grounding the inverter chassis may help. > Experimenting will be needed with and w/o this > ground to see which works better. > > Separate the radio receiver from the inverter as > far as possible. Distance is your friend here. > > Ham radio equipment tends to be less affected by > inverter RFI because the receivers are fed with > coaxial cable, which is self-shielding. The coax > is connected to antennas that are commonly 50-100' > or more from the inverter. > > There are some common steps you can try .. but in > the end .. steps unique to the particular site > may also be needed. > > > Dan > > > > --- On Thu, 6/17/10, Darryl Thayer <[email protected]> > wrote: > > > From: Darryl Thayer <[email protected]> > > Subject: Re: [RE-wrenches] AM noise on batteryless > inverters > > To: "RE-wrenches" <[email protected]> > > Date: Thursday, June 17, 2010, 11:30 PM > > I have heard that putting small ferrite donuts > > around the AC and DC wires will reduce this > > noise. Place them inside the inverter. they are > > avaiable from DigiKey > > Darryl > > > > --- On Thu, 6/17/10, jay peltz wrote: > > > > > From: jay peltz <[email protected]> > > > Subject: AM noise on batteryless inverters > > > To: "RE-wrenches" <[email protected]> > > > Date: Thursday, June 17, 2010, 8:35 PM > > > HI All, > > > > > > Say I've had a question from a client about AM > radio > > > noise from his battery-less inverter. > > > > > > I'm wondering if there is any other folks out > there > > > who have found this to be problem? > > > > > > Now I realize that most people listen to AM in > the > > > evening when the inverters are non-op so this > > > might not be a problem for most people. > > > > > > Thanks in advance, > > > > > > jay > > > peltz power > > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
