AIMS Inverter Interference Problem

[blueslegend]

I have a neighbor ( 10 or 12 houses away) with an AIMS inverter that is spewing noise from 1.8mhz through 50mhz. This radiation can be heard up to 3/4 mile away. Any, that's ANY wiring connected to the a/c outputs, whether an extension cord or merely a test lead from a volt meter acts as an antenna and radiates on the afore mentioned freqs. Are these units FCC type accepted I wonder, because this unit's interference to a licensed station flies in the face of so many FCC rules I can't even count them.  What has the group found about filtering these units, has anyone had any discussions with the manufacturer on this issue? Any help would be appreciated. Thanks for reading.

[SparWeb]

It may not be grounded to earth properly.

Are you on good terms with this neighbour?

Are you able to conduct your own investigation of how it's connected?

Have a look at the AIMS installation instructions, and perhaps call the company about discrepancies you find.

[Flux]

I don't know much about the N American inverters or the strange centre tapped distribution system but I also think the trouble will be lack of grounding.

All European cheap inverters have the case isolated from battery or mains circuits, but all the filters are referenced to the inverter case and if that is not properly grounded the filters don't work and may make the noise worse.

There is a lot of potential for these inverters to generate RF noise but the manufacturers make a decent effort to contain it with suitable filters. Sometimes

there can be local noise within a building but it doesn't radiate any distance. Some of the inverters I have tried are no worse than the average PC as far as noise goes.

Flux

[blueslegend]

Relations are 'cordial' at the moment. We did check to see that there was not a ground loop and did not find that to be the case. I was told that some torroids on the outputs may help. But it needs to get a lot better and very soon.  This has been on-going for over a year. It has taken me this long to find the culprit. The next step is to contact the FCC field office in Tampa. After that it's in their hands. This should be a lesson for 'harry homeowner types' that want to save on the cost of 'juice', and do the installs themselves.  The equipment has to be good, reliable and installed right. If a contractor had installed this no doubt the homeowner would be after HIM to make it right. But since it wasn't I get the feeling that he feels like I will have to live with it. Nothing could be farther from the truth...I've been doing so for the last year and that's over.  It is admirable to save on the cost of a/c, it may even be neccessary. But it cannot be at the someone else's expense or inconvenience. I like the neighbor and hope we can get this straightened out. I have offered to pay for the parts, the torroids, whatever. Let's see what happens.  - M

[Ungrounded Lightning Rod]

Check with the manufacturer, giving the model and serial number, too.

I had a similar problem with a Goulds Pumps "balanced flow" well pump controller.  This is a soft-start, variable speed, motor controller that uses a switching regulator to vary the speed of a three-phase pump motor to provide water at the correct pressure for any given flow - with a sensor and a TINY pressure tank (to provide pressure until the pump starts and gets up to speed and allow pressure to vary gradually for the pressure sensor's benefit) rather than a BIG pressure tank (to hold pressure between runs of a start/stop pump).  The switching regulator noise completely blanketed any radio reception in the house or near it.

Turns out the model had been recalled and supplanted to fix exactly that problem.  They sent me a new controller (and PUMP!).  Problem solved - new one is just BARELY detectable at particular frequencies at the end of the AM dial if you tune around looking for it.

(I heard later that the authorized dealer no longer was.  I suspect he was supposed to have junked the older model and instead sold it to my contractor, thus causing a service problem for Goulds...)

[dnix71]

How do you know that it is his inverter that is causing the interference and not something he has hooked up to it?

If this is a modified sine wave inverter it could be causing something that was designed for a sign wave do strange things.

[dnix71]

Have you completely unloaded the inverter (not disconnect)?

[dnix71]

This thread here:

http://www.sailnet.com/forums/gear-maintenance/46428-inverter-powering-laptop-3.html

Someone mentions Aims and another says marine rf interference is common among the cheap cigarette lighter inverters sold for car use.

My Aims 300 pure sine has NO FCC registration cert. It doesn't even have a UL or CSA, just a CE logo.

[Clifford]

It is unclear from your initial posting...

Is the neighbor "off grid" or "on grid".

I.E.  is he feeding his power back into the grid and causing these interference problems at all the neighbor houses, or just in his house?

Like some others have commented, it could either be the inverter itself, or the interactions of the modified sine wave with stuff that is plugged in.  I know my computer and other equipment doesn't like "modified sine" as well as "true sine", but it does work reasonably well.

I've wondered about feeding modified vs true sine into the "grid".  But, there certainly are regulations for grid attached systems... one of them being proper manual and automatic shut-offs so if the grid goes down, power will not be backfed into lines where power company workers could be working.  I don't believe that AIMS sell grid-attached inverters.

[blueslegend]

The inverter in question was taken OFF LINE. That is, it was turned off and the supply lines FROM it to the breaker panel that was installed for it, were disconnected as well.  These were extension cords.  At this time, the noise COMPLETELY disapeared. When the unit was switched back ON, the noise was STILL gone, but when anything was plugged into it, an extension cord, the supply lines to the breaker panel or a volt meter, the unit begins to radiate. Anything plugged in becomes an antenna, radiating the RFI being produced. I sent AIMS an email about this particular case last Sunday. They have not felt the need to respond to me. This is ok because a higher authority may just be contacting them. It appears that this dilema is befalling a number of the amatuer radio operators around the country. All one has to do is to read PART 15 of the FCC Rules to understand how copable the USERS of these devices are. Yes, it's the USERS of the equipment, which are responsible for their use, in your homes, wherever. The manufacturers at this point may not have to answer for it just yet, but when you guys buy them and their useage begins to drive people around you crazy, the end result is that you'll just be sending them back to whatever manufacturer is peddling these things. I'd like to think that someone has built a better mousetrap, an inverter that works in harmony rather than to create chaos. So far NOT so good. So is it the BRAND of inverter or just what?  You guys may have the answer.