The RFI kit is designed to suppress RFI caused by Solar micro-inverters, power optimizer, and solar arrays by electrically isolating the “antenna” wires used to connect the various devices.The cabling between the PV array, the micro-inverters or power optimizers and their connection to the electrical bus combining their individual outputs can be considered “antennas” for the pulse switching circuits of the individual devices thereby causing radiation at very low fundamental frequencies with harmonics that can cause undesirable radio interference in the 1-30 MHz (and sometimes higher) frequency range.This interference may be objectionable to the owner of the solar installation as well as neighbors who may also experience the interference to their electronic devices.
THE RFI KIT FILTERS ONLY SUPPRESS COMMON MODE CURRENT (SIGNALS) THAT ARE COMMON TO ALL WIRES IN THE CABLE, AND DOES NOT EFFECT INDIVIDUAL DIFFERENTIAL SIGNALS ON EACH WIRE. THE FILTERS HAVE NO EFFECT ON THE NORMAL SIGNALS CARRIED WITHIN THE CABLE.
Power Optimizer RFI
Ferrite cores (slip on) have the two (+/-) cables from the solar array module thru the middle of the core and the two wires hooked to the “string” connecting the optimizers together. Suppressing RFI on all wires in and out of the optimizers helps to reduce any broadband RFI “noise” generated in the SOURCE switching circuits (typically at 200-1000 KHz and harmonics thereof). Two ferrite filters are required for each optimizer – we recommended Part # PV-RFI-PO (includes two ring filters). See typical installation diagram below:
A simple ferrite ring filter on the DC power line can help suppress the RFI noise affecting the victim device or keep the DC power cord from acting as an antenna and radiating RFI into other victim devices. This kit is also useful on laptop computer supplies, routers, cable modems, wireless phone charges, etc.
Installation is quick and easy: Just wrap the DC power cord through the center of the ring filter as many times as you can and reinstall. For best results with long DC power lines, use one at the ring filter at the wall wart end (to prevent the wall wart power supply from using the DC line as an antenna) and another at the DC plug end (to prevent the electronics in the powered device from using the DC power cord as an antenna). Typical installation is shown below:
The filter suppresses RFI in from .1-100 MHz. Inside diameter is 3/4 inch/19 mm.
Since most households and office environments have multiple wall warts we offer the Wall Wart RFI Filter kit in bulk quantity packages.
Known RFI Generators include Roku/Sling-TV power adapter - Interference heard in the AM broadcast band and harmonics. Also many ethernet Cable/DSL modems, cell phone chargers, computer power adapters have the same issue: using the AC or DC side of the power supply as a radiating antenna. RFI solution is to use a linear power supply, change adapters or wall wart ferrite filters