[RFI] Inverters?

Sun Sep 20 13:05:35 EDT 2020

My standby generator is *not* portable and is a split-phase 240 VAC alternator  It’s a 13 kW natural gas fueled Generac unit. It’s air cooled and says it’s not intended for 24/7 use. That said, we’ve had to use it for a couple of days on end and it’s been reliable. The 24/7-rated units are all liquid cooled; none of the air-cooled units are. No matter what, I’ll have to change the oil and filter every 50-100 h on this unit so it’ll have to be stopped for that. It also burns more oil than a liquid cooled unit, so that needs monitoring as well. 

While it has a large potted regulator module and another potted battery charging module in it, it is always RF-silent. 

Kim N5OP

"People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith

> On Sep 20, 2020, at 11:25 AM, Charles Gallo <charlie at thegallos.com> wrote:
> 
> I have an EU 2000. Only place I can hear it (I’ve tried a few different setups) is on 80m (note: not tried on 160)
> Took the extension cord for it, put a few (4? Would have to look) through a type 43, and then it was VERY hard to detect. I’ve been very tempted to open it up, and put the ferites right before the outlet, but haven’t 
> 
> --  
> 73 de KG2V
> Charlie
> 
>> On Sep 20, 2020, at 12:10 PM, Kimo Chun <kimochun at gmail.com> wrote:
>> 
>> All good advice. It is safe to assume that virtually all inverter
>> generators generate rfi noise. It is safe to assume that the bulk of their
>> market/customer doesn't care about or need clean outputs so they don't care
>> either. I used to have one of the last generation of completely shrouded
>> conventional Honda generators EX3300. It was stolen. I wish I had it now.
>> Honda doesn't make them anymore. Too bad.
>> 
>> Though I have not tested newer delivered models, the original EU1000 and
>> larger models all generate RFI. It was more prevalent/noticeable on lower
>> frequency bands, say 20m and lower. I have one EU1000 that was modified by
>> a top notch engineer/ham friend to minimize this. I don't have the details
>> nor have I taken it apart to learn what was done. I just bought it off him
>> as he was moving. We've successfully used homebrew inline common mode
>> chokes using Type 31 cores on AC extensions leaving the generators that
>> have worked OK. No, I didn't do measurement tests (I could) but it was fine
>> for our Field Day operations. For a fixed, longer term situation more
>> testing would be in order. A friend bought a Honda 7kw model that had the
>> same problem. I don't know if he was similarly successful. I didn't follow
>> up.
>> If you want to circumvent this issue purchase a conventional generator and
>> stay away from inverter types. Otherwise, be prepared to clean it up
>> yourself.
>> 
>> The other issue people don't pay attention to is generator design and
>> application. None of the typical home power backup generators (Generac,
>> etc.) offered are for continuous - off grid use. You can use them for some
>> hours per day or perhaps for a few days (see their instructions) at a
>> time.  If you are looking for near continuous power after a hurricane for
>> possibly a few weeks (your fuel problem notwithstanding) you need a much
>> better, different generator designed for that. It will often run at lower
>> RPM and have other heavy duty design features which require significant
>> monitoring and maintenance.
>> Or use their commonly sold one and pray and accept their failure. Say,
>> purchase a new one after each major use, assuming it did last through that
>> event. Perhaps a viable risk.
>> 
>> 73, Aloha
>> Kimo Chun KH7U
>> 
>> 
>> 
>> Date: Sun, 20 Sep 2020 06:46:45 -0700
>> From: Dave Cole <dave at nk7z.net>
>> To: rfi at contesting.com
>> Subject: Re: [RFI] Inverters?
>> Message-ID: <58123b6c-8262-97ab-1929-dfb0c78f0b51 at nk7z.net>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>> 
>> The best test is to bring a portable shortwave radio, and listen before
>> you buy...  Most places, have a demo generator set up.Make it clear to
>> the vendor that if the unit is generating RFI you will be returning it,
>> with the expectation of a full refund.
>> 
>> 73, and thanks,
>> Dave (NK7Z)
>> https://www.nk7z.net
>> ARRL Volunteer Examiner
>> ARRL Technical Specialist, RFI
>> ARRL Asst. Director, NW Division, Technical Resources
>> 
>>>> On 9/19/20 9:23 PM, Warren Wolff via RFI wrote:
>>> ? I am considering the purchase of an emergency back-upgenerator.? For
>> the first time, I have encountered unitstagged as ?inverters?.? Does this
>> mean that some systemsare AC generators while the ?Inverter-types?
>> generateDC and then convert it to AC?? ? ?Inverter? immediatelyprecipitates
>> the worry of RFI.? Comments, please.
>>> WarrenW7WY
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