i’ve also noticed noticed the cheep generators vary. the 60hz wave alot. good
ones seem to hold it
> On Sep 21, 2020, at 7:57 AM, Hare, Ed W1RFI <w1rfi@arrl.org> wrote:
>
> When QST reviewed generators a few years back, we noticed a wide range in the
> stability of the motor speed and thus voltage vs load. For some, when we
> keyed a kW amplifier, the motor speed remained pretty steady. For others, the
> motor speed dropped significantly, then picked up, but during the drop, the
> voltage dropped as low as 60V from a 120V generator. If the amp remained
> keyed, the motor picked up speed again, but then when unkeyed, the speed and
> voltage rose. This would be a show stopper for high-power portable
> operations.
>
>
> ________________________________
> From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Jim Brown
> <jim@audiosystemsgroup.com>
> Sent: Sunday, September 20, 2020 11:45 PM
> To: rfi@contesting.com <rfi@contesting.com>
> Subject: Re: [RFI] Inverters?
>
> Hi Warren,
>
> Several observations. First, buying ANY generator for anything more than
> FD operation should be done as an engineering project. Some of the
> design criteria are
>
> 1) what are your loads? Grab a clamp-on Ammeter and measured them --
> don't go by nameplate, which are always worst case. Don't have a
> clamp-on ammeter? It's a VERY important tool to own. Look for one that
> measures relatively SMALL currents -- you want 5-10A full scale, maybe
> 20A or 30A. Unless you're seeing very large loads, nothing more than 50A.
>
> 2) Our average load 24/7 is less than 1kW; it goes up (a lot) when
> cooking with electricity, running A/C, contesting legal limit, and a
> bit with large fans that are part of an HVAC system.
>
> 3) Does your gen need to run well motors? My EU6500 Honda (inverter) gen
> does NOT like to run my well motors. A traditional gen half that size will.
>
> 4) How much of your loads need to be on gen? I found that I could run my
> 22 cu ft fridge, computers, lighting, and moderate size home
> entertainment system on my Honda 2000i in economode. To do that, I had
> to have some of those loads redistributed between legs of 120/240 so
> that all I needed for those functions were on the same leg. Easy to do
> at the breaker panel. Our cooking is propane, so I boil water for coffee
> on the stove when on the gen. Don't try to run the microwave.
>
> 5) Consider propane. My EU6500 has been converted, W6GJB converted his
> 2000i, and is going to do mine. A $22 can runs 20 hours or more in
> economode, depending on loading.
>
> 6) Doing county expeditions in very quiet places for CQP and 7QP using
> W6GJB's 2-position contesting trailer with antennas on a pneumatic mast
> and the gen on the back of the pickup it's hitched to, we found that we
> needed a good noise filter. The one that Glen and I came up with was
> added to the Handbook a few years ago. If it's not in yours, you can
> find details in the latest version of k9yc.com/RFI-Ham.pdf I should
> plug directly into the gen -- it's the AC cable that radiates noise
> common mode, the filter kills that.
>
> This filter is designed for HF; for 6M and above, see my recent
> recommendations for coax TX chokes for VHF/UHF, using them as a
> guideline for AC cable the size of the coax in those recommendations.
> For 6M, use two turns of RG8 through a Fair-Rite #31 1-in i.d. clamp-on;
> for best suppression, use 2-4 of these 2-turn chokes in series. See the
> photo in the pdf.
>
> 7) As others have noted, consider duty cycle. Most low cost gens, even
> the good ones, are designed for intermittent operation. My most
> demanding need when on geen is keeping the fridge cold enough to prevent
> spoiling. When running the 2000i, I typically keep the duty cycle below
> 60%.
>
> 8) It's important to realize that worst case loads are usually starting
> a motor; once the motor is running, the load drops a LOT. It's starting
> my well motors that the EU6500 doesn't like. When in doubt, START your
> gen with no load on it, then connect the load, and once it's stabilized
> (usually under a minute, could be more with well motors), then kick it
> down to economode to save (a lot of) fuel.
>
> Master DXpeditioner AA7JV, drastically reduced the amount of petrol he
> had to carry on the boat for his trips by using power amps that could
> run on batteries that were float-charged by the generators running in
> economode. George is a VERY smart engineer, and one of my heroes!
>
> 73, Jim K9YC
>
> On 9/19/2020 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
>> _______________________________________________
>> RFI mailing list
>> RFI@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>>
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