[PLUG] UPS shopping

Ted Mittelstaedt tedm at portlandia-it.com
Sun Dec 31 06:43:54 UTC 2023


Interesting I have a smaller 5000k Generac, gasoline powered also.  But it's old-school with the generator output directly feeding single phase 240 power.
It runs at 3600rpm and the armature is a 2 pole so the formula yields 60Hz

Small generator power is actually -very- clean far cleaner than utility power as long as the load is constant.  When the load changes the frequency fluctuates and that induces spikes and sags.

Modern "home house" generators seem to run at a slower speed with little regulation and are double-conversion, the fluctuating AC output is rectified to DC then that feeds a sinewave power inverter.  The rpm is considerably lower because an engine running at 3600 rpm puts out a lot of noise.

Triplite Isobar power strips are the "gold standard" in power cleanup, supposedly.

Ted


-----Original Message-----
From: PLUG <plug-bounces at lists.pdxlinux.org> On Behalf Of Dick Steffens
Sent: Saturday, December 30, 2023 5:03 PM
To: plug at lists.pdxlinux.org
Subject: Re: [PLUG] UPS shopping

On 12/30/23 16:00, Ted Mittelstaedt wrote:
> The problem with generators is that the frequency is dependent on how 
> fast the rotor spins and the second you put an electrical load on A generator you increase the magnetic field resistance to the armature and the generator slows down.
>
> When the generator is the size of a barn at Bonneville Dam and the 
> armature weighs 10 tons and you turn on your coffee pot the massive 
> inertia in the generator armature will not slow measurably
>
> When it's your Champion generator the armature slows measurably and the frequency then gets lower until the engine's governor gives it more fuel to compensate then the frequency returns to normal.
>

That makes sense. The generator I used to have (I think it was a
Generac) was gasoline powered. I got it when I worked for EC Company. It was stolen a number of years ago. I got the Champion because of the dual fuel feature. I never had a problem with using the UPS boxes with the Generac.

It's not a big deal, since I don't have to have my computers running during power outages anymore. But if there is something I can use between the wall and the UPS that would clean up the generator's power, that would be useful.

Thanks.

--
Regards,

Dick Steffens



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